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Change log

Here is the change lot extracted from the latest release.

version 5.0.0
dated 2016-05-05

  - Initial and incomplete HTTP/2 support.

    To enable, add a "2.0" string to your Robot::http_versions array. By
    default, Servers detect HTTP/2 magic "PRI..." prefix and switch to
    HTTP/2 mode automatically but that behavior may change.

    Polygraph currently only supports simple HTTP/2 transactions. No
    support for multi-frame headers, connections with concurrent
    streams, encryption, authentication, large Cookies, HTTP/2-specific
    options, etc.

  - Initial support for Dumb Unreliable Stream Protocol (DUSP).

    DUSP is a made-up UDP-based protocol intended to simulate "video
    streaming".  Each transaction consists of a (small) request and a
    (large) reply.  Request consists of a single small UDP datagram.
    Reply may consist of multiple UDP datagrams.  Polygraph DUSP Robots
    support SOCKS5 proxies.  Multiple new PGL fields were added for DUSP
    agent configuration:

    * Agent::xact_timeout - DUSP transaction timeout on client and
      server side. Client timeouts if it does not receive server reply
      packets. Server timeouts if it does not receive client heartbeat
      packets. By default there is no timeout.
    
    * Agent::packet_size - DUSP server packet size. Currently, cannot be
      larger than 16KB. Default is 16KB.
    
    * Agent::message_bit_rate - DUSP server message bit rate.  If set, a
      DUSP server produces a Poisson packet stream modeled using an
      exponential distribution with a mean packet rate corresponding to
      the specified packet size and bit rate. Otherwise, packets are
      sent with no delay.  Not yet supported for DUSP clients/requests.
    
    * Robot::heartbeat_rate - DUSP client heartbeat interval.  If set,
      DUSP client sends small "heartbeat" packets at a given rate.
      Otherwise, no heartbeat packets are sent.
    
    Polygraph collects and reports basic DUSP stats including reply
    size, reply rate, packet delay, and packet loss.

  - Allow PGL integer, numeric, size, and time constants to be used as
    const() distributions.

    Also convert zero integers to const(0) distributions, not undefined
    distributions. After this change, workloads that [ab]used zero
    values for undefined distributions will work differently. For
    example, if Polygraph treated a particular undefined configuration
    field by disabling a feature, it will now enable that feature with a
    zero-valued constant distribution as a configuration parameter. Such
    workloads should be changed by using undefined values instead of
    zeros:

        req_inter_arrival = undef();

    It is our hope that such 0-abusing workloads are very rare.    

  - Support restricting SslWrap::protocols to "TLSv1.1" or "TLSv1.2".

  - Collect and report connection encryption and segment-usage stats.

  - Bumped binary log version.

  - Support blocking (but cached) DNS lookups when resolving KDC server
    names at test configuration time.

    Prior to this fix, Polygraph client assumed that KDC server
    addresses are IP addresses (and silently used 0.0.0.0 address when
    they were not). Now, Polygraph client resolves the configured domain
    name and refuses to start the test if there was a resolution error.
    
    Optional DNS caching is used to cache these new blocking DNS lookup
    results. Polygraph robots are reusing the dns_resolver.cache for
    these blocking lookups. When testing with many robots, configuring
    that cache is probably essential to ensure reasonable startup times
    without DNS errors.
    
  - Report OPENSSL_ia32cap environment variable if it is set.

  - Use GCC optimization levels set by autoconf (usually -O2)
    instead of our custom platform-specific levels.

    Linux builds will now get -O2 instead of -O1 in most cases (+5%?).
    FreeBSD builds will now get -O2 instead of -O3 in most cases (-3%?).

  - Made aggregate interval and phase "all responses" stats the same.

    Authenticating transactions were missing from the phase-based stats,
    causing confusing same-name different-value rep.* lx lines.

  - Fixed certificate generation by SMP workers.

    Add SMP worker ID to the certificate file name hash so that SMP
    workers generate same-configuration certificates without overwriting
    each-other certificate (and supplementary) files.

  - Fixed FTP 150 processing bug that resulted in CLOSE_WAIT client
    connections. Polygraph may have also refused to transfer FTP data.

    Dealing with FTP 226 responses could hit the same bug if the server
    neglected to send an FTP 125 or 150 response first.

  - lp:1380660: Make failed if gcc 4.9 is used.

  - Avoid harmless "NetAddr.cc:159: addrN().known()" warnings.

  - Fixed GCC -Wstrict-overflow warnings.

  - Fixed reporting of Maximum Resident Size values exceeding 2 GiB.
    This change decreases precision of the reported values a little.

  - Do not dump core when exiting on logging errors.

  - Formatted code using uncrustify and attractifier (via UniForm).


version 4.9.0
dated 2014-10-22

  - Support SSL-to-proxy: Robots connecting to HTTP forward proxies
    using SSL.

    To configure the new feature, the robot must mention an address of a
    use()d PGL Proxy object. The PGL Proxy object must have an ssl_wraps
    field configured. This tells the robot that the forward proxy is
    accepting SSL connections.

    When a Robot needs to connect to an SSL origin server while using
    SSL-to-proxy, the combination results in two independent "nested"
    SSL layers: One from the robot to the proxy and one from the robot
    to the origin server. The robot sends an HTTP CONNECT request
    (encrypted and, hence, invisible to a 3rd-party observer!) inside
    the outer SSL layer to the proxy.

  - Support requesting and/or serving on-disk files. Configured via PGL
    Content.document_root, similar to an Apache httpd document_root.
    Polygraph preloads all regular files from Content.document_root into
    RAM, scanning document_root sub-directories recursively. Empty files
    and files exceeding 2GB in size are currently not supported. When
    configured, Polygraph responds to a request with URI path FOO using
    the content preloaded from the document_root/FOO file on disk.

  - Quit ASAP after reaching a negative phase goal instead of waiting
    for server virtual "cold" phase to become idle and time out.

  - Exclude the time spent waiting for the first transaction from the
    first phase by adding a virtual "wait" phase before the scheduled
    real phases.

    The wait phase ends when the first transaction begins and should get
    no transaction or connection measurements. Wait phase stats are not
    logged because there should not be any, and because logging them
    would add noise to test reports.

  - Added PGL Agent::http_headers field to specify custom HTTP headers.
    PGL constants that look like 'name: value' are now parsed as PGL
    MimeHeader objects:

          MimeHeader B = 'B: valueB';
          MimeHeader C = 'C: valueC';
          MyRobot.http_headers = [ 'A: valueA', [B, C]: 30% ];

    Agent::http_headers is a new kind of PGL "selector" that, for every
    selection, goes through all the listed custom headers and selects
    each header with the specified probability. In the above example,
    Polygraph will emit requests with headers A, B, and C in 30% of all
    agent-generated messages while putting just the header A in the
    remaining 70% of all messages. Note that header A is always added,
    while headers B and C are either added _together_ (30% of cases) or
    not added at all.

    If a PGL-configured header clashes with a Polygraph-generated header
    (or with another PGL-configured header), then the first added header
    wins, and Polygraph logs a warning. PGL-configured headers are added
    first so they should always win against the Polygraph-generated
    headers such as Date, Host, Accept, and Connection. However, this
    feature was not really designed for overwriting Polygraph-generated
    headers but for adding new/different ones.

  - Start SMP workers, one per local Bench host, if Bench.*_side.hosts
    are used. To create N SMP workers on host a.b.c.d, use N a.b.c.d
    hosts (the PGL clone operator ** is handy for that).

    If the Bench hosts array contains a single local host, no worker
    processes are started (i.e., the master process becomes the worker
    process). This allows Polygraph to run in "legacy" non-SMP mode in
    simple Bench configurations.

    Changed --worker ID default to zero. The zero value is used for the
    Master process because it may create its own logs that should not
    overwrite worker logs.

  - Support running each SMP worker on a configurable set of CPU cores.
    Also usable in a degenerative case of a single worker (no SMP). Not
    supported on systems w/o sched_setaffinity() API, such as FreeBSD.

    The feature is configurable via the new PGL BenchSide::cpu_cores
    field.  Each integer array nested inside cpu_cores represents a list
    of CPU cores (i.e., a CPU affinity mask) for a single worker. If a
    cpu_cores field is defined, the number of its masks must be either
    zero or equal to the number of BenchSide's hosts array elements; any
    other number is a fatal configuration error. Empty array is treated
    as if no cpu_cores array was configured/defined. We may change this
    [rather low-level] configuration approach based on user feedback.

    Without cpu_cores configured, Polygraph does not try to restrict
    workers CPU affinity.

  - When generating random content, support optional "data" or "binary"
    format when the new Content.generator field is set to "random_data".

    This is handy when the DUT treats the default mostly-ASCII content
    specially, but the tester does not want to use cdbs to generate
    something other than ASCII content.

    Note that new "random_data" format is virtually uncompressible,
    unlike ASCII that carries more than 25% "fat". Workloads using SSL
    compression or other compression mechanisms may see a substantial
    different in performance, even without a DUT.

    The default behavior is still to use a subset of printable ASCII
    characters.  That algorithm can now be explicitly configured by
    setting Content.generator to "random_text".

  - Re-fetch Kerberos TGT ticket if it is needed, but we failed to fetch
    it before. The code already dealt with expired and unusable TGT
    cases by re-fetching, but a missing TGT led to a persistent stream
    of "(c157) missing Kerberos TGT" errors.

  - Better reporting of authentication errors: Report such details as
    KDC server address, robot identity, and connection information.

  - Better reporting of SSL errors: Minimize the number of logged
    Comments when detailing a single error.

  - Simplified table(filename) PGL calls and command line options: Do
    not require explicit distribution type but get it from the loaded
    table instead. Old syntax with an explicit type is still supported.

  - Fixed rep.rate evaluation in Phase scripts. Polygraph was returning
    request rate instead of the response rate. The two rates are usually
    similar, which may explain why the bug went unnoticed for years.
    Logged and console-reported stats were not affected.

  - Fixed KDC error handling: Polygraph was not switching to the next
    configured KDC server on KDC connection failures.

    Also, final TGT ticket fetch failure (no retries left) now leads to
    the cancellation of all previously queued ticket transactions.
    Prior to this change, the queued ticket transaction waited forever
    if the TGT transactions kept failing.

  - Count HTTP authentication errors once, not twice.

  - Avoid segfaults when cleaning up Kerberos state, especially after
    many KDC timeouts.

  - Prevent InAddress::sockAddr() assertions when deleting IPv6 aliases
    on FreeBSD.

  - Avoid year-2038 overflows when running 32bit ltrace --objects time.

  - Made modern autotools happier and bootstrap.sh safer.


version 4.8.0
dated 2014-05-20

  - Tie Robot.req_rate to "baseline" transactions and report just the
    baseline transactions on console i-lines, avoiding user surprises
    when, for example, enabling authentication doubled perceived request
    rate. A baseline transaction delivers the intended resource to the
    client and may include individual HTTP CONNECT or authentication
    transactions as intermediate steps of a single compound transaction.

    This is a significant change, affecting offered load in
    workloads using HTTP CONNECT requests and/or HTTP authentication.

    Collect and report interval stats for HTTP CONNECT and
    "authenticating" transactions.  Exclude HTTP CONNECT requests from
    "ssl" interval stats so that only transactions actually using SSL
    are recorded there. Report an active i-proto line, even if all its
    transactions have failed.

    Binary log version, some lx object names, and HTML report blobs have
    changed to reflect the new statistics collection approach. More
    related cleanup work is probably needed.

  - Negotiate/Kerberos proxy authentication support, configurable via
    PGL KerberosWrap. Both UDP and TCP transports are supported for
    communication with KDC. MIT Kerberos v1.9 or newer is required. No
    Heimdal support.

  - Support a configurable cache for successful DNS lookups via the new
    PGL DnsCache type and DnsResolver::cache field. No DNS caching by
    default.

  - Added PGL zoneDomains(file_name, ip_addresses) function to load
    domain names from DNS zone files. Only domains that match given IP
    addresses are loaded.  Wildcard domains are ignored.

    DNS zone file interpretation is implemented using libldns. Libldns
    does not allow any leading whitespace in zone files, even on
    otherwise empty lines.  The library supports $ORIGIN directive.
    Tested with libldns v1.6.16.  Polygraph tries [too] hard to fix
    known ldns.h interface bugs. If libldns is not available, cannot be
    fixed, or is not compatible with Polygraph expectations, a
    ./configure warning is printed and any test calling PGL
    zoneDomains() will fail at call time.

  - Control SSL compression via the new PGL SslWrap::compression field
    which specifies the probability that the agent using the SslWrap
    configuration will try to use SSL compression. The agent decision is
    sticky. Disabling compressions appears to be required to enable SSL
    (AES-NI) hardware acceleration support, at least in some
    environments. Note: SSL compression is a messy feature in general,
    and Polygraph specifically does not have full control over SSL
    compression.

  - Better SMP support (more SMP automation work is still needed):
      * Added --worker command line option to specify SMP worker ID.
      * Support %worker macro in command line option values.
      * The local r.n.g. seed value now defaults to worker ID. This
        change does not affect old test scripts running new Polygraph
        versions because the default worker ID is one, same as the old
        local r.n.g. default.
      * Added worker() PGL function to return the current worker ID.
      * "${worker}" macro support in ips2names, credentials, URL traces.
      * pgl2ldif --worker ID command line option.

  - Revised detection of important differences reported by cmp-lx.pl
    based on real-world regression tests to minimize noise. For example,
    very rare (less than 0.1%) errors are no longer considered important
    and absolute differences below 1 millisecond are no longer reported
    for time measurements done with millisecond precision.

  - Infect content by appending Request URI information to the response
    body if the newly added PGL Content::inject_object is set to a
    "request_uri" string. This helps caches that do not store multiple
    copies of identical response bodies, especially in tests using cdbs
    with a small number of verbatim entries.

  - Accept "A" values for DnsResolver::query_type. They are still the
    default.

  - Report an active i-proto line, even if all its transactions have
    failed.

  - Revamped Reporter's baseline (a.k.a. executive stats) scope
    formation and use, to better handle cases where client- and
    server-side phases differ.

  - Support patches that "register" themselves with Polygraph so that
    Polygraph binaries can report which patches have been applied.

  - Do not enable SSL support if libssl is missing or has no
    SSL_connect(), even if OpenSSL headers are present.

  - Remove old IPv6 addresses when creating new aliases. Fixed(?)
    primary interface address detection on Linux. We currently define
    "primary" as the address added to the interface first. Also fixed
    IPv6 aliases deletion.

  - Fixed handling of concurrent HTTP Negotiate transactions when one
    transaction changes the proxy need for authentication after the
    other transaction has already started with a different assumption.

  - Fixed collection of transaction queue time statistics.

  - Fixed default libz (compression support) detection for systems with
    AX_CHECK_ZLIB serial 8 macro.

  - Fixed StatCycle.cc:82 "0 < cat < count" assertion.

  - Avoid division by zero "floating exception" when producing
    dynamize()d domains for empty worlds. If we need to produce a new
    URL but cannot (due to an empty local world), then repeat from a
    non-empty remote world (if possible).

  - Fixed dumping of cdbs with "binary" entries. They used to be
    truncated.

  - Prevent cdbEntries.cc 'e.model' assertion by rejecting misconfigured
    Content that has content_db containing "markup" objects but lacks a
    may_contain field necessary to generate/pour those objects.

  - Fixed computation of histogram percentiles by cml-lx.pl tool.

  - Fix segfault in PGL parser on some invalid workloads.

  - Install the documentation files during "make install".

  - Remove AX_* macros from cfgaux/, use system versions instead.
    Autoconf-archive package is now required for bootstrapping.


version 4.7.0
dated 2013-04-19

  - Configurable SSL certificates.

    A new PGL SslWrap::certificates field allows to configure existing
    certificates for Polygraph client and server use.  Each certificate
    file should contain an unencrypted certificate and a private key in
    PEM format.  The key may be followed by intermediate certificates to
    form a chain (see SSL_CTX_use_certificate_chain_file(3)).
    Certificates are assigned to Agents in a round-robin fashion and the
    assignment is sticky.

    This feature is supported on both client and server sides.  If the
    same SslWrap object with certificates is used for both Robots and
    Servers, they would end up using the same certificates.

  - Generated client-side SSL certificates.

    Polygraph used to generate server certificates only.  A new PGL
    SslWrap::generate_certificates boolean field now explicitly controls
    whether Polygraph should generate SSL certificates.  The field is
    honored on both client and server sides.  The default behavior has
    not changed: certificates are not generated on the client side and
    are generated on the server side.

    Setting SslWrap::generate_certificates to false allows running
    server without any certificates.  This is a weird but valid
    configuration.

  - Collect and report SSL session resumption phase statistics.

    "Count" and "rate" phase stats are available for new and resumed SSL
    sessions.  On client side, both offered (i.e. resumption attempts)
    and measured stats are collected.  On server side, only measured
    stats are collected.  In addition to count and rate stats, SSL
    session resumption probability is reported.

    In the future, we may add offered SSL session stats on the server
    side and collect interval stats.

  - Content-driven popularity model support.

    A new ClientBehavior.pop_model PGL field added.  Similar to other
    ClientBehavior properties, it allows setting Robot popularity model
    when requesting a particular Content type.

  - Binary log compression.

    Compression is enabled at build time if and only if zlib library is
    available.  All Polygraph tools support reading both compressed and
    uncompressed logs.  A compressed log size for a simple workload is
    less than 20% of the uncompressed log.

    Other than smaller log sizes, no user-visible changes are expected.
    In particular, we do not expect log compression to slow Polygraph
    down, but more experience is needed to confirm that.

  - Inherit previous phase factors at runtime (by default).

    If the next phase "begin" factor is not explicitly configured, it is
    inherited from the corresponding "end" factor of the previous phase.
    Before the change, this inheritance was implemented at test start
    time so when a phase would end [by its script] prematurely, the
    factor would jump from the last value in the previous phase to the
    implicitly set "begin" value in the next phase.  Now, the "begin"
    value is computed only when the next phase starts, avoiding the
    jump.

  - Polymorphic min() and max() PGL functions.

    Before the change, PGL min() and max() functions converted their
    arguments to float for comparison.  Hence, the functions failed for
    argument types which cannot be converted to float, such as time.
    Now, arguments are compared using PGL '<' and '>' operators,
    allowing min() and max() functions to be applied to such types as
    time and rate.

  - More flexible PGL string to int and float conversion.

    Before the change, PGL string to int and float conversion functions
    did not allow any spaces after the number, which resulted in obscure
    errors and inconveniences, especially when dealing with numbers loaded
    using PGL system() calls.  Now any trailing spaces are ignored.
    Note that leading spaces were already ignored before the change.

  - Allow unit scales and boolean constants as PGL function and
    object names.

    Before the change, time and size scales and boolean constants were
    not allowed to be PGL function or object names.  In particular, this
    resulted in parsing errors for workloads using min() PGL function or
    scripts using objects like sample.rptm.min.  Now PGL parser can
    distinguish bare constants from function calls and object names.

  - Select Robot HTTP version on startup and report it.

    Before the change, Robot HTTP version was selected on session start.
    Hence, Robot HTTP version could be changed during a test with
    multiple sessions and it could not be reported on startup.  Since
    sessions are not meant to model different HTTP clients, such
    behavior is wrong.  Now HTTP version selection for Robots is sticky
    and performed early during startup, the same way it is done for
    Servers.  As a side-effect, Robot HTTP versions are now reported on
    startup.

  - Stop Robots when all phases are complete.

    Polygraph client no longer starts new transactions after completing
    the phase schedule and right before exiting.  Such transactions could
    lead to annoying proxy and server errors.

  - Support PGL print() call outside of Phase scripts to assist with
    debugging complex workloads and annotating console logs.  For now,
    output printed outside of scripts does not get to binary logs.

  - Add printV() function for PGL scripts to print at a given verbosity
    level.  The first argument should be an integer specifying the
    desired verbosity level.  For example:

      printV(1, "An important message ", 123);

  - Polish the error message when PGL type conversion fails.

  - Polish client error message when a Robot fails to load the
    configured root certificate.

  - Improve large table distribution (e.g. array selectors) support.
    Table distributions with up to 10240 entries should be supported
    now.  Larger distributions may still result in failures.

  - Refuse to add directories to cdb.

    Before the change, the cdb tool did not check if input file is
    really a file.  It would try to open and process a directory as if
    it was a file, which may succeed on some systems and result in
    unexpected DB content.  Now cdb checks whether input file is a
    regular file and skips it if it is not.  If stat(2) is not
    available, the check is not enabled and cdb behaves as before.

  - Fix handling of CONNECT tunnels requiring multiple CONNECT
    transactions.  Do not switch to SSL until CONNECT tunnel is fully
    established.  In particular, this fixes workloads using both HTTPS
    (SSL) and proxy NTLM authentication.

  - Fix NTLM authentication statistics for compound transactions.

    During the first authentication Robots cache the authentication
    scheme.  In subsequent requests, Robots send appropriate
    authentication headers right away in the first request.  Before the
    change, a compound transaction was created only during the first
    authentication resulting in missing compound stats for subsequent
    NTLM authentications.

  - Fix HTML report generation if a phase name contains spaces.

  - Fix segfault for workloads using foreign trace without any Content
    objects (an uncommon but valid configuration).

  - Fix segfault on test shutdown before warmup stage is complete.

  - Fix potential reporter segfault on some truncated logs.

  - Fix errors and warnings when building with GCC v4.7.

  - Code cleanup and minor changes.


version 4.6.0
dated 2012-05-07

  - Add reachedPositiveGoal() PGL script call, propagate positive
    goals to servers.

    A new reachedPositiveGoal() call allows to stop phases from
    runtime watchdog scripts.  The effects of the call are the same as
    reaching any other positive goal (e.g. Phase duration or
    transaction count).  If multiple client processes are in use,
    calling reachedPositiveGoal() in one client process is not
    sufficient - the synchronized phase will not really stop until all
    clients are done with it.

    Positive goals are now propagated from clients to servers.  This
    means that when all clients reach positive goals, servers would
    also reach a "propagated" positive goal.  This was implemented to
    propagate reachedPositiveGoal() calls from clients to servers in
    the first place (servers do not run watchdog scripts) but it works
    for any positive goal.  Currently, there is no way to disable this
    behavior.  In the future, if we find out that there are cases
    where servers should resist phase changing on client-side positive
    goals, we can probably add a phase.goal.mandatory or similar flag
    to give users more control.

  - Per-IP explicit port manager (--ports option) for client and
    server.  Before the change, explicit port manager had a single
    port history for all IP addresses.  This makes explicit port
    manager a poor performer when we use 1000 robots with 1000
    different IP addresses.  Now it does proper per-IP port tracking.

    This change increases Polygraph memory usage for clients and
    servers using explicit port managers.  Each explicit port manager
    for 1024:65535 range uses ~250KB of memory.  A workload with 1000
    IP addresses would require additional ~250MB of RAM.

  - Make retried transactions obey request inter-arrival
    distribution and, hence, Robot::req_rate setting.

    Transactions may be retried due to several reasons like aborts,
    pipeline races, authentication.  Before the change, retried
    transactions did not obey request inter-arrival distribution.
    This resulted in "extra" traffic and higher request rate which
    feels wrong and is confusing.  Retries are now handled in the same
    way as embedded objects: retried transactions are started
    immediately but further requests are delayed to obey configured
    request rate.

  - Interactive figures in HTML reports using jqPlot.

    There are two kind of figures now: static and interactive.
    Static figures use regular images as before, while newly added
    interactive figures offer advanced features:

      * resizing
      * zooming
      * line toggling

    By default, all figures are shown in static mode.  One can
    switch between static and interactive figures using the links in
    the top right corner.

    A modern browser is required for interactive figures.

    Interactive figures are implemented using jQuery, jQuery UI, and
    jqPlot Javascript libraries.  The libraries are included in Web
    Polygraph distribution and are installed into the data directory
    (/usr/local/share/polygraph by default).  Web Polygraph must be
    installed (make install) for reporter to work.

  - Other fixes and improvements for figures in HTML report.  In
    particular, empty ranges warnings from gnuplot are fixed which
    makes reporter output much less verbose and more readable in some
    cases.

  - Enable SSL certificate extensions when making certificates using
    OpenSSL x509.  According to x509(1ssl) manual page, without the
    -extfile option, OpenSSL x509 command will not add extensions to
    the certificate.

  - Remove OpenSSL x509 -extensions option as not needed.  The
    section with certificate extensions can be specified in the
    OpenSSL configuration file instead.

  - Fix client segfault on shutdown before warmup is complete.

  - Fix client and server segfault when PGL string array is use()d.

  - Fix reporter segfault on some truncated logs, print warning when
    log is truncated.

  - Fix segfault and assert in ltrace introduced by detailed
    content-type stats changes in v4.5.0.

  - Fix pgl2ips segfault when there are many hosts or agent types
    configured.

  - Fix several segfaults and bugs in polymon tool.

  - Add help screen for polymon (press 'h' or 'H' key).

  - Fix undefined blob reference errors in reporter for one-sided phases.

  - Fix build on FreeBSD 7.2.

  - Remove unused --tmp_dir option for reporter and comparator.

  - Code cleanup and minor changes.


version 4.5.0
dated 2011-11-01

  - Add detailed content-type stats.  Before the change, only
    aggregated size stats were collected for individual content
    types.  Now, Polygraph collects and reports aggregated stats,
    histograms, and traces for content types, including both size
    and response time stats.

  - Support longer tests.  Before the change, Polygraph used 32bit
    integers for stats, OIDs, and related code.  When running very
    long and/or very high-load tests (e.g., a few days at 10Gbps
    speeds), 32bit counters could overflow resulting in weird
    errors and assertions.  Now Polygraph uses 64bit integers for
    all counters, OIDs, and related code, avoiding overflows.

    Note: Since Polygraphs prefers to keep URL lengths constant,
    the length of Polygraph URLs and dynamic domain names have
    increased.  Polygraph URL path length changed from 42 (e.g.,
    /w184f4bb3.78a56c48:00000008/t03/_00000001) to 50 (e.g.,
    /w184f4bb3.78a56c48:00000008/t03/_0000000000000001).  Dynamic
    domain name prefix length changed from 7 (wNNNNNN) to 17
    (wNNNNNNNNNNNNNNNN).

  - The above changes may result in significant binary log size
    increase for some workloads.

  - Increase minimum supported log version due to the above
    changes.

  - Replace MINSTD (described in "Random Number Generators: Good
    Ones Are Hard To Find" by Stephen K. Park and Keith W. Miller)
    rng with the Unix rand48().  The rand48() rng allows us to
    generate 32 random bits as opposed to 31 bit from MINSTD.  This
    lets us implement 64bit rng by generating two random 32bit
    numbers.  Besides the rand48() rng demonstrates better results
    in dieharder tests.

    This change affects random variables generated by Polygraph,
    hopefully for the better. For example, we observed more precise
    distribution of protocol choices during a regression test using
    HTTP and FTP transactions.

  - Send Host header in HTTP CONNECT requests.  Per RFC 2616, a
    client MUST include a Host header field in all HTTP/1.1
    request messages.  Before the change, Polygraph did not send
    Host header in CONNECT requests.

  - Fix multiple bugs related to IPv6 alias creation on Linux (at
    least).  The bugs led to Polygraph assertions and corrupted
    IPv6 addresses being created.  Now, Polygraph can successfully
    create IPv6 aliases on Linux (at least).  Currently, in
    contrast with IPv4, Polygraph does not delete old IPv6 aliases
    before creating new ones.

  - Fix IPv6 alias support in the polygraph-aka tool.  Now it can
    successfully create IPv6 aliases (at least on Linux), e.g.:
    polygraph-aka lo '[::3]'.

  - Work around a bug on FreeBSD when many IPv6 aliases are
    created on a real network interface.  Polygraph tried to use
    the aliases immediately after creating them and apparently
    before they were fully configured.  The problem affects at
    least FreeBSD 7.2.

  - Fix build with OpenSSL libraries with disabled SSLv2 protocol.
    In particular, this fixes build on Debian Weezy.  Workloads
    using SSLv2 will be rejected if Polygraph was built without
    SSLv2 support.

  - Fix persistent working set ID reporting when loading the
    stored set.  Before the change, a new ID was generated each
    time the set was loaded.

  - Cleanup copyright preamble to make Debian folks happier: add
    copyright statements where missing, remove copyright from
    generated config.h file, update copyright years, replace "(C)"
    with "Copyright".

  - Remove files specific to the Windows build which has not been
    supported for a while.

  - Code cleanup and minor changes.


version 4.4.0
dated 2011-03-28

  - Content-driven recurrence support: ClientBehavior.recurrence
    PGL field added. Similar to other ClientBehavior properties,
    it allows setting Robot recurrence for a particular Content
    type.  For example, a Robot can now be configured to revisit
    images more often than movies. The feature is documented at
    http://www.web-polygraph.org/docs/userman/content-driven-robots.html.

    The object ID (oid) generation and management algorithms have
    been changed to support content-driven robot recurrence.
    Polygraph clients now have to synchronize a larger number of
    smaller distributed oid sets (a.k.a. "worlds"), especially for
    workloads with a large number of distinct content types.

    As a result of these changes, BHR discrimination has fewer
    side-effects now. Before these changes, the BHR discrimination
    algorithm affected content type selection. This could make
    actual content type distribution and recurrence ratio
    different from the configured ones, especially for workloads
    with embedded objects.  After these changes, the traffic
    should better match the PGL configuration.

    No significant changes in traffic patterns are expected for
    high-performance workloads not using BHR discrimination.

  - Added PGL system() function. The function accepts a single PGL
    string as an argument, treats that argument as a shell
    command, executes the command, and returns the standard output
    of the command as a PGL string value.

    Outside Phase scripts, the system() function is equivalent to
    a back quoted `command` and is executed only once at startup.
    Inside Phase scripts, the system() function is executed every
    time the script is run, unlike back quotes which are executed
    only once at startup, even in a Phase script context

  - Taught PGL int() and float() functions to convert PGL strings
    to integer and floating-point numbers. Implicit conversion
    from strings to numbers are still not allowed.

  - Fixed assertion when a container PGL Content type uses an
    embedded PGL Content that was not configured yet.

  - Fixed layout of tables printed on the console (e.g. "Server
    content distributions" and "Phases").

  - Code cleanup.


version 4.3.2
dated 2011-04-05

  - Fixed assertion when a container PGL Content type uses an
    embedded PGL Content that was not configured yet.

  - Fix build with OpenSSL libraries with disabled SSLv2 protocol.
    In particular, this fixes build on Debian Weezy. Workloads using
    SSLv2 will be rejected if Polygraph was built without SSLv2
    support.

  - Fixed layout of tables printed on the console (e.g. "Server
    content distributions" and "Phases").

  - Fix persistent working set ID reporting when loading the stored
    set. Before the change, a new ID was generated each time the set
    was loaded.

  - Cleanup copyright preamble to make Debian folks happier: add
    copyright where missing, remove copyright from generated config.h
    file, update copyright years, replace "(C)" with "Copyright".

  - Remove files specific to Windows build which has not been
    supported for a while.


version 4.3.1
dated 2011-03-03

  - Better support for trace replay: Ignore Robot.origins field
    for PGL Robots with foreign-only interest. Before the change,
    non-empty Robot.origins field was required, even if it was
    unused because the Robot has no interest other than replaying
    the foreign trace.

  - Better support for trace replay: Do not "warm up" Robots with
    foreign-only interest. Before the change, many workloads
    containing trace-replaying Robots could get stuck in the first
    phase due to an infinite warmup. Now, foreign-only Robots do
    not affect the warmup, and the first phase ends as expected.

  - Print the corresponding workload file line and number for many
    PGL-related warnings and errors.

  - Fixed client crash on exit when Robot.accept_content_encodings
    PGL field is set.

  - Fixed generation of lifecycle-related entity parameters when
    the same ObjLifeCycle object is used multiple times in the
    workload. The bug resulted in unexpected entity-header (e.g.,
    Last-Modified-Time and Expires) changes when the same URL was
    revisited.

  - Fix statistics recording for aborted transactions. Before the
    change, non-basic (e.g. POST) aborted transactions were
    recorded in the wrong category (e.g. post). Now, all aborted
    transactions are recorded in the aborted category.

  - OpenSSL 1.0 support (LP:690599).

  - Fixed epoll(2)-related bug which could result in "Socket not
    connected" and similar errors.

  - Fixed select(2) support in SSL-related workloads.

  - Code cleanup.


version 4.3.0
dated 2010-12-10

  - Content-driven Robots support: The user may configure Robot
    behavior based on Content. Real HTTP client behavior often
    depends on web site and its content.  Content-driven Robots
    help simulate those dependencies.

    All for-Robot settings in PGL Content objects are grouped
    under the new Content::client_behavior field. A new PGL
    ClientBehavior type is added. Assigning PGL Robot to
    ClientBehavior and vice versa is supported. Once Server and
    Content are selected, Content::client_behavior settings, if
    any, overwrite the corresponding Robot fields.

    For now, the following three Robot behavior properties can be
    specified on per-Content basis: req_types, req_methods, and
    ranges.

  - Considerably improved the randomness of distribution values
    tied to URLs, such as response sizes. The old distributions
    could have too many similar values, with too few extreme
    values, especially when non-unique worlds (--unique_world no)
    were used with multiple PGL Servers and table-based
    distributions.

  - Linked object blobs from traffic stream tables in report.

  - Fixed poll(2)-related bug which could result in "Socket not
    connected" or similar errors on platforms without epoll(2)
    support such as Mac OS X.

  - Multiple world support for distr_test tool: The world_count
    option is intended to simulate URL-based value generation in
    workloads with multiple PGL Servers, each Server being a "oid
    world" for the Robot. By default, world_count is 1, and all
    oids are generated from a single world. If world_count is
    greater than 1, distr_test generates oids from multiple
    worlds. The number of oids generated from each world is
    (trials count / worlds count).

  - Minor fixes and code cleanup.


version 4.2.2
dated 2010-11-05

  - Added custom stats: The user may configure which transactions
    are added to custom stats based on HTTP status code.
    Configuration is done with Agent.custom_stats_scope PGL field:

      custom_stats_scope = ["all", "-2xx", "+30x", "+206"];

    If a transaction finishes before getting a reply, or there is
    no HTTP status code for another reason, the transaction is not
    included in the custom stats.

    The following custom stats are collected: custom.rep,
    custom.live.rep, custom.projected.rep. Custom stats are
    accessible from PGL phase scripts.

  - Fixed PGL TblDistr to produce the same results for the same
    seed. For example, if a table distribution is used for
    response body sizes, the response size would stay the same
    when the same URL is visited multiple times.

  - Fixed several build and startup problems on Mac OS X.

  - Fixed a DummyNet-related build problem on FreeBSD 8.1.

  - Fixed IPv6 address parsing in command line arguments.

  - Fixed segfault when parsing a PGL array or list with a
    malformed item.

  - Allow IPv6 addresses in PGL to start with '[:'.


version 4.2.1
dated 2010-10-14

  - Transaction lifetime support: Allow the user to limit the
    lifetime of client and server transactions via the new PGL
    Agent::xact_lifetime field. A transaction aborts when its
    configured lifetime expires. Aborted transactions are treated
    as errors on client and server sides of the test, for now.

    Client transaction lifetime includes both connection slot
    waiting time (if any; see Robot::open_conn_lmt) and regular
    execution time. Server transaction lifetime includes both think
    time (if any; see Agent::xact_think) and regular execution time.


version 4.2.0
dated 2010-10-08

  - Allow PGL scripts to monitor in-flight or "live" transactions
    so that they can adjust load even when many transactions get
    stuck or slow down and do not immediately contribute to regular
    postmortem stats.  Measure how long live transactions have
    been running (live.rep.rptm) and how many response bytes they
    have read (live.rep.size). Make these new stats available to
    PGL scripts via the regular stats interfaces
    (currentSample().live.* and currentPhase().live.*).

  - Added projected.rep.* statistics that combines live and
    finished transaction stats. Available to PGL scripts only.

  - Treat an HTTP CONNECT response as the end of the transaction.
    Collect and report stats dedicated to these new CONNECT-only
    transactions. These CONNECT transactions are often rather
    different from the in-tunnel transactions that follow.
    Isolating them also prevents CONNECT overheads from polluting
    the first in-tunnel transaction stats.


version 4.1.2
dated 2010-11-06

  - Fixed PGL TblDistr to produce the same results for the same
    seed. For example, if a table distribution is used for
    response body sizes, the response size would stay the same
    when the same URL is visited multiple times.

  - Fixed several build and startup problems on Mac OS X.

  - Fixed a DummyNet-related build problem on FreeBSD 8.1.

  - Fixed IPv6 address parsing in command line arguments.

  - Fixed segfault when parsing a PGL array or list with a
    malformed item.

  - Allow IPv6 addresses in PGL to start with '[:'.


version 4.1.1
dated 2010-10-07

  - Add dump command to the cdb tool, which stores all verbatim and
    link-only objects into individual files. Cdb dump accepts an
    optional --as "path/prefix${name}.suffix " parameter. Default
    --as value is "./cdb${name}". ${name} macros are substituted with
    1,2,3,4... integers.

  - Cdb interface has changed. Commands (add, dump, show) are passed
    as options with database argument, i.e. cdb --show test.cdb.

  - Limit PGL load and population factors value to [0%, 100%] range.
    Print error and exit if begin or end factor value is greater than
    100%. If a script changes factor to a negative or greater than
    100% value, print warning and set the factor to 0%/100% instead.

  - Set Recursion Desired (RD) flag for outgoing DNS queries because
    some modern resolvers do not accept queries without that flag
    and because we do not recursively resolve ourselves.

  - Skip already configured network interface aliases when creating
    new ones if delete_old_addrs option is false.

  - Do not send Content-MD5 header with HTTP 206 (Partial Content)
    responses. This fixes segfault and is in line with HTTPbis.
    See http://trac.tools.ietf.org/wg/httpbis/trac/ticket/178

  - Fix assertion during network interface alias creation.

  - Fix errPersistButNoCLen error on client-side when multi-ranges
    and persistent connections are enabled. Content-Length is not
    required if message uses the media type "multipart/byteranges".

  - Fix LP:644813: SSL issues with DNS and embedded objects.

  - Fix address space size check for SpreadAs.

  - Fix multiple alias range support in the aka tool.

  - Fix compilation of the msl_test tool on Linux.

  - Make out-of-memory handler more robust.

  - Minor fixes and code cleanup.


version 4.1.0
dated 2010-05-13

  - Support SOCKS5 proxies for HTTP, HTTPS, and passive FTP
    traffic (socks_proxies and socks_prob PGL Robot fields).  No
    support for Active FTP data connections yet.  "None" and basic
    "username/password" SOCKS authentication methods are
    supported. Chaining SOCKS and HTTP proxies is supported (the
    socks_chaining_prob PGL Robot field).

  - Extend the ipsToNames() PGL function to support a domain name
    generation template with ${dashed_ip} and ${port} macros. This
    change allows more flexibility in naming a large number of
    server domains.

  - Add a dynamize() PGL function that converts an array of static
    domain names to dynamic names (using the supplied renewal
    percentage), similar to what the dynamicName() function does
    to one static name. This change allows creation of a large
    number of servers, each with a unique dynamic domain name.

  - Do not send "100 Continue" control response if we got the
    entire request body already. This fix prevents POST requests
    sent without waiting for 100 Continue response from getting
    stuck because the client sent everything and cannot continue.

  - Fix server freeze when "Expect: 100-continue" request headers
    and body (partial or complete) is received in a single read(2)
    call.

  - Fix assertion when an HTTP client aborts transaction.

  - Fix abort position calculation on the client side. The abort
    size was set bigger than the request size, and client aborted
    after the request was sent, during response reading.


version 4.0.11
dated 2010-11-06

  - Limit PGL load and population factors value to [0%, 100%] range.
    Print error and exit if begin or end factor value is greater than
    100%. If a script changes factor to a negative or greater than
    100% value, print warning and set the factor to 0%/100% instead.

  - Fixed PGL TblDistr to produce the same results for the same
    seed. For example, if a table distribution is used for
    response body sizes, the response size would stay the same
    when the same URL is visited multiple times.

  - Fixed several build and startup problems on Mac OS X.

  - Fixed a DummyNet-related build problem on FreeBSD 8.1.

  - Skip already configured network interface aliases when creating
    new ones if delete_old_addrs option is false.

  - Do not send Content-MD5 header with HTTP 206 (Partial Content)
    responses. This fixes segfault and is in line with HTTPbis.
    See http://trac.tools.ietf.org/wg/httpbis/trac/ticket/178

  - Fix assertion during network interface alias creation.

  - Fix errPersistButNoCLen error on client-side when multi-ranges
    and persistent connections are enabled. Content-Length is not
    required if message uses the media type "multipart/byteranges".

  - Fix assertion when an HTTP client aborts transaction.

  - Fix abort position calculation on the client side. The abort
    size was set bigger than the request size, and client aborted
    after the request was sent, during response reading.

  - Fix LP:644813: SSL issues with DNS and embedded objects.

  - Fix address space size check for SpreadAs.

  - Fixed IPv6 address parsing in command line arguments.

  - Fixed segfault when parsing a PGL array or list with a
    malformed item.

  - Allow IPv6 addresses in PGL to start with '[:'.

  - Fix multiple alias range support in the aka tool.

  - Fix compilation of the msl_test tool on Linux.

  - Make out-of-memory handler more robust.

  - Minor fixes.


version 4.0.10
dated 2010-04-13

  - Ignore ssl_wraps for FTP servers because we do not really
    support FTPS yet.

  - Servers with ssl_wraps no longer verify SSL peer certificates
    because verification causes an optional peer certificate
    request, which some proxies do not ignore but abandon their
    man-in-the-middle decryption instead.

  - In PGL arrays using well-known strings (e.g., protocol names),
    reject unknown names that share a common prefix with the known
    ones.

  - Fixed spreading of array probabilities that do not add up to
    100%. Only the first such array in the workload had its
    probabilities adjusted.

  - Raised verbosity level of FYI and warning messages from 0 to 1
    to minimize zero-level output.

  - Fixed segfault in ltrace that rendered the tool unusable.

  - Fixed logging of very long messages.

  - Fixed memory leak in pgl2ips.

  - Minor man pages and spelling fixes.


version 4.0.9
dated 2010-02-14

  - Used newer autotools: automake v1.10.2 to v1.11 and autoconf
    v2.63 to 2.64.

  - Added polygraph(7) and individual man pages for each binary.

  - Added cmp-lx.pl --precision=percent option to ignore relative
    measurement differences below the specified percentage.  The
    default is 10 percent. Zero percent shows all, including
    identical, measurements. Other fixes for cmp-lx.pl.

  - Added header_size/body_size field at the end of "--dump sum"
    log line. This change may be reverted in future releases.

  - Added rng_seed option for distr-test tool.

  - Allow apostrophe and a few other non-alphanumerical symbols in
    PGL comments.

  - Detect the lack of SSL support and quit with an error for SSL
    workloads.

  - Fixed HTTP authentication for SSL connections.

  - Do not assert if an agent address lacks a netmask.

  - Delete old IP aliases by name, not by index, to avoid having
    lo:1 without lo:0. May need more work.

  - Warn about duplicate network interface addresses instead of
    asserting that there are none.

  - Fixed a segfault when retrieving IPv6 addresses from a network
    interface.

  - Removed tcp2xmld as unused.


version 4.0.8
dated 2009-10-01

  - New addressing scheme called Spread. It is possibly the
    simplest addressing scheme that distributes the load evenly
    across all hosts, unlike the PolyMix-4 addressing scheme that
    does not add a host until existing hosts are 100% utilized.

  - Allow the user to specify alias addresses explicitly,
    overwriting the "concatenate PGL agent addresses" default.
    This allows defining several Server kinds (e.g. plain and SSL)
    and then spreading their aliases across all hosts.

  - Add size and response time phase stats for all HTTP response
    status codes received by polyclt and sent by polysrv. The
    measurements are collected for all transactions, including
    failed and non-basic ones. See the new "HTTP reply status..."
    tables in the report.

  - Add tools/cmp-lx.pl script to compare two tests and print
    important differences. Test logs must be preprocessed with lx
    first.

  - Print warning if Content-MD5 header is present but malformed.

  - Polished generated reports: Sort a few tables, number and link
    report generation notes, stretched histogram plots, make
    one-page summary fit.

  - Comply with Filesystem Hierarchy Standard (FHS) and Debian
    Policy requirements:
      * set default installation prefix to /usr/local
      * install workloads to share/polygraph/workloads
      * rename polyclt/polysrv to client/server
      * replace '_' with '-' in binaries name (pop_test to pop-test)
      * add polygraph- prefix to all binaries during installation
      * strip .pl prefix from Perl scripts during installation

  - Fix "content type mismatch" regression error with reporter log
    processing.

  - Fix negative open connection level and ttl stats.

  - Fix reporter crash when it is called with the --phases option
    and the phase does not exist. Warn if a phase does not exist.

  - Fixed parsing of ":sup" ranges in table distributions.

  - Fix "inconsistent computation of unseen_objects" report error.

  - Fix "reference to an undefined blob
    'object.all_proxy_validations...'" reporter error.

  - Quit nicely when the reporter runs out of memory.

  - Fix (potential) double delete errors.

  - Made more modern compilers happier.

  - Remove gnuplot build dependency.

  - Do not link with libnsl on platforms where libnsl is not used.


version 4.0.7
dated 2009-07-15

  - Support origin server authentication for Robots. Foreign
    origin servers are supported as well.

    Unlike real browsers, Robots do not support or remember nested
    paths. For example, if the /foo/bar/ path got authenticated,
    the same Robot would go through the entire authentication for
    /foo/bar/baz/ even though a real browser would probably try to
    reuse the first (higher-level directory) authentication
    information instead.

  - Support cookie-based Robot authentication, including that with
    foreign URLs. Robots now have their own private cookie storage
    and queue. Cookie Max-Age parameter is parsed and honored.
    Stale cookies are not sent.
    
    Cookie path and domain parameters are still ignored as if they
    were not sent.

  - Support active FTP mode (i.e., FTP PORT command). Configured
    using Robot's passive_ftp field. The default is 100% passive.

  - Added pgl2ips tool that takes a PGL workload and prints agent
    IP addresses that a test would use.

  - Added modulo operator support for PGL integers. Useful for
    flipping coins in PGL Phase scripts.

  - Users no longer need to patch system headers to get more file
    descriptors on Linux: Polygraph now ignores FD_SETSIZE limit
    when using poll(2) or epoll(2), which is the default on most
    platforms.

  - Exit gracefully on SIGTERM (SIGINT as supported earlier).
    Killall sends SIGTERM by default and we were getting truncated
    console logs because of that.

  - Better HTTP cookies support: honor expires/discard options and
    support cookie updates. Do not send cookies that do not fit.

  - Better handling of and error reporting in HTTP 401, 403, and
    407 corner cases.

  - Polished FTP error reporting.

  - Limit SSL error reporting frequency to minimize noise during
    high-performance tests with many SSL errors. Polished
    reporting.

  - Better reporting of tests with different client- and
    server-side PGL workloads.

  - Better reporting of foreign trace configuration errors.

  - Removed some expensive mallocs.

  - Removed unseen object blobs and unknown (zero and N/A) rows in
    stream and object tables from the HTML report.

  - Allow tabs where were spaces allowed in PGL.

  - Fixed memory leaks.

  - Fix alias creation bug when workload contains both generated
    and manually configured aliases. Some aliases were created on
    many hosts while others were not created on any hosts.

  - Fixed misleading 'unknown log file format' error when the
    named binary log file is not found by lx, ltrace, or reporter.

  - Fixed error handling code that was ignoring certain fatal
    errors.

  - Made more modern compilers happier.

  - Ignore zero-valued Content-Length in GET instead of
    terminating the server transaction with the "unexpected
    Content-Length header" error. Some proxies add that header to
    some GET requests.

  - Fixed select(2) support (unused on most platforms by default).

  - Report that content types differ and exit instead of asserting
    when a report is generated using logs with mismatched content
    types.

  - Do not send body in HTTP HEAD response. This fixes a bug that
    resulted in "malformed HTTP request or response line" errors
    on the client side when Range requests were used.

  - Work around crashes in OpenSSL versions older than 0.9.8c:
    http://objectmix.com/apache/674160-apache-start-segmentation-
    fault-emlink-too-many-links.html


version 4.0.6
dated 2009-04-20

  - Added support for FTP STOR to robots and servers, triggered by
    selecting the new "Upload" request type in PGL
    Robot::req_types.
    
    STOR transactions use PGL content configuration, including cdb
    support, just like PUT transactions already do.

    Robot::put_contents PGL field is replaced with
    Robot::upload_contents. The old put_contents field is still
    supported, with a deprecated warning.

    Request method selection code adjusted to select PUT/STOR
    method for HTTP/FTP transactions if "Upload" request type is
    chosen.

  - When parsing and generating URLs and related addresses, handle
    default port with respect to the protocol scheme (80 for HTTP,
    443 for HTTPS, 21 for FTP).

  - Make the test quit when phase error goal is reached.  One of
    the goals here is to prevent automated tests from getting
    stuck forever.

  - Added a PGL Phase.primary boolean field. If any of the phases
    have that field set, those phases and only those phases should
    be used for the executive summary and the baseline report. The
    new field is logged when phase stats are logged. This change
    resulted in the log version increase to v17.

  - Skip phases without stats when trying to guess which phases
    should be included in the baseline report and the executive
    summary.

  - Added initial set of 13 workloads for regression testing to
    workloads/regression/. These workloads need more work.

  - Report when phase positive/negative goal is reached for the
    first time.

  - When reporting stat phase progress say "waiting for WSS to
    freeze" only when the phase itself is actually locked, waiting
    for WSS to freeze. We used to report when polyclt was waiting,
    which was confusing in a phase progress report context.

  - Report more information about locked phases that may continue
    to run after reaching their explicit goal. This should help
    diagnose remaining problems with phases getting stuck when a
    test generates many errors.

  - Report IP address counts in addition to dumping (potentially
    huge) address arrays when local and PGL addresses do not
    match. Helps to identify addressing problems quicker.

  - Log details about server warmup plan start and completion.

  - Fixed nil pointer derefence bug when dealing with rare SSL
    tunnel establishment failures. User-visible bug effects are
    unknown but could include polyclt crashes.

  - Fixed epoll support in the presence of some connection errors.
    The bug resulted in some errors not reported to the user and
    an infinite loop.

  - Fixed agent alias allocation bug that resulted in identical IP
    aliases created on different hosts. The bug was exposed by
    workloads that randomized generated address order using PGL
    select() or slicing assignment.

  - Fixed stats collection for authenticated HTTP transactions.
    User-visible effects could include runtime assertions but the
    exact effects are unknown.

  - Deleted a questionable assertion being hit by users (during an
    error-rich test) when SSL tunneled transactions are in use.
    The exact cause of the assertion is still unknown and could be
    already removed by other changes.


version 4.0.5
dated 2009-02-05

  - Warn about "unusable" objects as arguments to use(). Skip such
    objects.
    
    Skipping unusable objects simplifies workloads where some
    agents or address maps become unusable if some workload
    parameter leaves them without any addresses. A common use case
    is a workload where agent addresses are selected using slicing
    assignments or select() function calls, with "ratio of
    such-and-such agents" as a configurable parameter.

  - Fixed SSL connection level accounting. The level was not 
    decremented properly, resulting in artificially high number of
    open SSL connections being reported.

  - Fixed oid management to avoid an assertion when dumping foreign
    request URLs and to dump more oid details.

  - Do not blab about configured SSL proxies and/or servers if
    there are none.



version 4.0.4
dated 2009-02-04

  - Added Robot.http_proxies and Robot.ftp_proxies PGL fields to
    support HTTP proxies dedicated to ftp:// transactions.
    Specifying an empty ftp_proxies array, disables proxying of
    those transactions.  The Robot.proxies field is now
    deprecated.  The overall logic is similar to how browsers can
    be configured to use different proxies for different origin
    server protocols. Polygraph still supports HTTP proxies only.

  - Added setAddrPort(addresses, newPort) PGL function call,
    returning original addresses but with each port is set to
    newPort. The function is useful for assigning a
    protocol-specific port to server addresses, when those
    addresses were selected or sliced from a larger address array
    used for many protocols.

  - Support https:// URLs in traces.

  - Support ${url_number} macro in URL traces. The substitution
    value is a "URL position in the trace" number that increases
    as the trace wraps. Using this macro, it is possible to create
    a virtually endless sequence of unique URLs using very short
    traces, which is useful for testing using specific URL
    patterns.

  - Significantly decreased startup times for workloads with thousands
    of agent addresses.

  - Fixed "FtpCltXact.cc:195: assertion failed: 'false'" on data
    connect errors.

  - Better handle various FTP RETR-related command sequences and
    server races.

  - Do not refuse to create agent aliases if some but not all
    agent addresses lack network interface names. Instead,
    ignore/skip nameless addresses in the alias:host mapping
    algorithm.
    
    This change helps when a workload mixes agents for which
    Polygraph should create aliases dynamically with agents for
    which the addresses are created before the test.

  - Complain about the lack of the root certificate once. When the
    number of SslWraps is large, complaining for each takes too
    much time and space, while there is little new information
    with each new complaint.
    
  - Do not warn if using non-ALL cipher for SslWrap. The default
    may be ALL:HIGH now and warning for each cipher takes too much
    time and space.


version 4.0.3
dated 2009-01-21

  - Support ${target_ip} macro in PGL-configured robot
    credentials. If found, the macro is replaced with the IP
    address of the target (i.e., true origin) server. This is
    especially useful for reverse FTP proxies that distinguish the
    true origin server by FTP user credentials.

  - Support empty robot passwords via "username:" credentials
    pattern.


version 4.0.2
dated 2009-01-19

  - Added initial support for PWD command. The directory we return
    always ends with a slash ("/") for now.
    
  - Revised FTP RETR logic to make 1xx responses required and to
    distinguish FTP 150 "Opening data connection" from the newly
    added "FTP 125 "Data connection already open; transfer
    starting" response.
    
  - Added initial support for user-configurable FTP origin server
    authentication. If no credentials are configured, the FTP
    transaction will use anonymous:anonymous@ credentials. For
    now, credentials are always supplied (i.e., the FTP
    transaction always tries to login to the server).
    
  - Use "227 Entering Passive Mode (,,,,)" format for PASV
    responses. Some FTP clients expect the parens because that is
    what FTP RFC uses, probably informally.

  - Be flexible when parsing FTP PASV response: search for the
    first digit as the start of a,b,c,d,p1,p2 sequence instead of
    assuming a fixed response format.

  - Fixed address map support: Agent protocol is determined by the
    target origin server and not by the visible server. Visible
    server may have no Agent configuration at all (e.g., if an
    address map is used in reverse proxy configurations).

  - Avoid polysrv assertions when a foreign URL or its size is
    requested without a subsequent request for a Polygraph URL.

  - Polished stats maintenance for FTP data connection.  Needs
    more work.

  - Made libtool 2.2.4 happier.


version 4.0.1
dated 2009-01-14

  - Pause FTP client transactions before writing a RETR command if
    the data connection has not succeeded yet.

  - Pause HTTP 100-Continue client writing when we are done
    writing HTTP request headers and are waiting for a 100
    Continue response from the server. Resume writing, if needed,
    when we get a response. Old code would waste CPU cycles and
    occasionally assert when checking whether it is possible to
    write the request body while we were receiving a response. May
    need more work.

  - FTP clients may send repeated PASV commands, especially if
    they try unsupported commands. If a PASV command is received
    when we are already listening or even accepted a data
    connection (but have not sent any data!), we simply close the
    data channel and open another one, assuming the client
    considers the old data channel unusable.

  - Treat 150 "Data connection opened" response as optional. We
    may not receive it if the server sent all data by the time it
    could generate a RETR response. Or, at least, that is what
    happens with Polygraph FTP server.

  - Wait for the data connection if the FTP server got RETR before
    it accepted the data connection: The client sending RETR
    cannot know whether its data connection was already accepted
    by the server. TODO: We need a timeout for this wait.

  - Finish with errFtpNoDataXfer ("FTP exchange terminated w/o
    data transfer") error when the FTP client did not RETR
    anything.  This prevents feeding an unclassified (no oid
    even!) but successful transaction to stats collection.

  - Fixed logging of request body content type meta-information
    for content types not used as server response content types.
    Partial meta-information led to core dumps during log
    extraction and analysis (also fixed).

  - Be more forgiving when encountering an unclassified
    transaction and when encountering a compound transaction
    without an authentication scheme. Both are bugs. We have not
    observed the former, but the latter does happen in some NTLM
    tests (and still needs to be fixed).

  - Report FTP port binding errors.

  - Report synchronous connect(2) errors for the data channel.
    May need more work handling the errors.
    
  - Check for asynchronous connect(2) errors for the data channel
    and terminate the transaction when they happen.
    
  - Made GCC v3.4.6 and v4.3.2 happier.


version 4.0.0
dated 2008-11-25

  - Added initial FTP client and server support. Robots use FTP
    for talking directly to an FTP server.  When a transaction
    ends at an FTP server via an HTTP proxy, robots use HTTP and
    ftp:// Request-URLs, as most real web clients would. Only
    passive FTP downloads are supported.

    Added a "protocol" field to the PGL Server type to specify
    the distribution of protocols. "HTTP" and "FTP" strings are
    accepted. Multiple protocols make sense if Server specifies
    multiple simulated servers using the addresses field. 

    Many FTP aspects require more work, such as support for more
    FTP commands and responses, FTP uploads, configurable FTP user
    authentication, better correlation with various HTTP-centric
    workload parameters, and a clear definition of an FTP
    transaction boundary for statistics collection.

    The code changes to support FTP were significant and
    widespread.


version 3.6.1
dated 2008-11-25

  - Removed unnecessary delays when processing log comments. The
    entire process (or even host) buffers and inodes were flushed
    with every console log message. The bug increased the time to
    process a single log comment significantly. The sync(2) delays
    become a noticeable problem when PGL watchdogs print a lot of
    custom statistics while Polygraph is working at the bench
    performance limit. The same probably happens when many errors
    are reported.

  - Fixed (enabled) statistics collection for socket write(2)
    calls.

  - Fixed assert failure when repeating foreign URLs from a trace.


version 3.6.0
dated 2008-09-22

  - Fixed URL selection algorithm: A change in URL selection code
    accidentally exposed an ancient bug that led to incorrect
    offered hit ratios. The bug remained unnoticed because the
    effect was negligible in most standard workloads. However, a
    significant difference in offered hit ratios can be observed
    in some custom workloads that used large portion of private
    URLs.

    Removed support for private URL worlds. Adding dynamic DNS
    feature (Polygraph v3.4.0) broke this support, offering false
    hits among private URLs. Hopefully, removing private URL
    worlds has no significant effect on standard workloads as this
    feature should only affect URL paths, which most DUTs treat as
    opaque.
    
    We may resurrect support for private URL worlds. The problem
    here is how to make private URLs use the same set of dynamic
    domain names as public URLs use. Since new names in public and
    private slices usually appear at a different speed, one
    category of URLs may use domain names that the other category
    stopped using long time ago.

  - Added authentication scheme stats. Response time and size
    stats are collected for each auth scheme separately. HTML
    report now includes "all auth-ing" (all authenticating) and
    "all auth-ed" (all authenticated) categories for individual
    HTTP transactions.  There is also "all auth" stats combining
    all categories.  The following log objects introduced:
    auth.none auth.ing.basic auth.ing.ntlm auth.ing.negotiate
    auth.ed.basic auth.ed.ntlm auth.ed.negotiate auth.none.

  - Added recurrence ratio stats. Put unique URL count and
    recurrence ratio to the executive summary table in the
    reporter.  Added url.unique.count and url.recurrence.ratio log
    objects.

  - Report various stats for compound transactions such as
    authentication transactions that may require several
    individual transactions before the final response is received.

  - Added SslWrap.ssl_config_file PGL field to set config file
    path for SSL certificate generation. The old 'myssl.conf'
    default is honored but deprecated.

  - Added SSL stats reporting. New SSL Load blob, similar to the
    old [HTTP] Load blob.  Added SSL hits and misses to stream and
    object tables. Made SSL stats available in scripts. The
    following objects added:
        ssl.xact.* - successful SSL transactions HR and levels
        ssl.conn.* - open SSL connections level stats
        ssl.err_xact.count - failed SSL transactions count

  - Added --hushed_error_tout option to polysrv and polyclt to
    configure error reporting frequency. This reduced log sizes
    for long tests designed to produce many errors.

  - Added stats for HTTP transactions exchanged using a CONNECT
    tunnel.

  - Polished generated HTML reports.

  - Fixed CONNECT regression bug introduced by NTLM authentication
    changes.

  - Fixed reporter initialization bug causing occasional coredumps
    and bogus results.

  - Fixed occasional parsing errors of chunked encoded message
    bodies.

  - Fixed assertion failure when handling an errors response to an
    "Expect: 100-Continue" request.

  - Updated running-out-of-RAM handling code that has not been
    tested for a while. This should remove a PolyApp.cc warning
    when Polygraph process starts.


version 3.5.0
dated 2008-06-22

  - Recognized authentication errors as transaction errors. It is
    now possible to write workloads that stop the test or decrease
    the load when there are too many authentication errors (using
    PGL phase goals or watchdogs).

  - Added epoll(2) level-triggered interface support. Epoll is now
    default on systems that support it (e.g., Linux). It should be
    faster than poll(2), the old default. Use the --file_scan
    command-line option to force poll if epoll gives you troubles.

  - Fix gcc 4.3 warnings and errors.

  - Removed deprecated acconfig.h that was causing ./configure
    warnings. Removed autotools-generated files from VCS control.


version 3.4.2
dated 2008-05-27

  - Fixed NTLM authentication of CONNECT requests.


version 3.4.1
dated 2008-05-22

  - Fixed 407 Authentication Required response handling: A v3.3.0
    regression bug resulted in "misdirected" errors for
    authenticated requests.


version 3.4.0
dated 2008-05-16

  - Support dynamic domain name generation using masks like
    '*.example.com:80'. The speed of new name generation is
    configurable and proportional to the miss rate. The number of
    names is frozen if the working set size is. Details at
    http://www.web-polygraph.org/test/docs/userman/dns.html
    
  - Added proxy authentication support for CONNECT requests.

  - Fixed CONNECT requests support (v3.3 regression bugs).


version 3.3.1
dated 2008-04-29

  - Report gzip-specific headers correctly for range responses.

  - Fix assert failures when using gzip encoding or range requests
    with bodies from a content database. Mixing range requests,
    gzip-compressed content, and cdbs now works correctly.

  - Fixed v3.1 regression bug: Uninitialized theBodyParser member
    led to occasional polyclt segfaults.


version 3.3.0
dated 2008-04-17

  - Support configurable POST/PUT content. Request body content
    configuration is very similar to how response content is
    configured. Content databases (cdbs) are supported. Actual
    request content type properties are measured runtime and
    reported by the reporter.

    Standard workloads have been updated. Custom workloads must be
    updated if you are using POST or PUT request types. Use
    cntSimpleRequest content defined in contents.pg to mimic old
    behavior.

    Details and configuration examples at
    http://www.web-polygraph.org/docs/userman/req_bodies.html

  - Detect proxy validation requests (i.e., transactions where the
    proxy converts a regular GET request into an If-Modified-Since
    request, most likely because it has the content cached but
    considers it stale).  Collect stats for useful and useless
    proxy validation requests. Useless validation requests are
    those resulting in a 304 Not Modified response (i.e., the
    cached content is still fresh).

    Added "Validation effectiveness" table to generated reports.
    This helps to analyze the effectiveness of proxy validations.

    Added "Cheap proxy validation hit ratio" table to the
    generated reports. The reported hit ratios are calculated as
    if useless proxy validation requests are so cheap that they
    should not be counted as server accesses for the purpose of
    hit ratio calculation.

  - Added basic statistics for messages without bodies and
    messages with unknown body content types. Requests with body
    have an "unknown" content type on server side. Messages with a
    non 2xx status and a body also have an "unknown" content type.

  - Fixed report generation bug leading to occasional garbage in
    the report text.


version 3.2.1
dated 2008-03-25

  - Polished stat object names related to Range request
    generation.

  - Fix segfault when server replies to HEAD request and attempts
    to pour body.

  - Fixed Proxy-Authenticate scheme parsing bug that was causing
    random segfaults during authentication tests (Qiao Yang at
    IronPort)


version 3.2.0
dated 2008-03-19

  
  - Added support for generation of Range requests and responses,
    including configurable single- and multi-range Range requests,
    single Content-Range responses, and multipart/byterange 
    responses.

  - Fixed "undefined assert()" compilation error on Ubuntu Gutsy.


version 3.1.5
dated 2008-03-13

  - Initial and mostly untested support for NTLM/GSSAPI proxy
    authentication. We need to find a proxy that supports
    NTLM/GSSAPI to test this feature.

  - Added support for recycling or sharing SSL certificates that
    have identical generation parameters. The support is enabled
    by setting PGL SslWrap::sharing_group to a non-empty string.
    The certificates within the same group will be shared if their
    openssl generation commands are the same.
    
    Sharing provides significant speedup in Polygraph start times
    when hundreds of servers require certificate generation.
    
  - Some Linux kernels have gettimeofday bugs that cause time
    jumps of approximately 72 minutes, especially on SMP systems.
    We saw it on an 8-CPU box running 2.6.18-8.el5. For 2002
    discussion, start at
    http://www.kernel-traffic.org/kernel-traffic/kt20020708_174.html#1
    
    We now try to ignore individual jumps exceeding 60 minutes. If
    the time did change, the change will be honored during the
    second gettimeofday() call.

  - Make NTLM code compile when SSL is disabled. Polygraph will
    assert if NTLM is used without SSL support because it needs
    SSL code for NTLM.

  - Removed extra terminating CRLF after CONNECT headers.


version 3.1.4
dated 2007-11-12

  - Use the first (top) supported Proxy-Authenticate method
    instead of the last one.

  - Use the last '@' in NTLM credentials to separate the host name
    from the user name because the user name itself may contain '@'.

  - Robots were not parsing some CONNECT responses correctly.

  - Send full Request URL only if we are talking directly to a
    proxy. Sending an HTTP request inside the CONNECT transaction
    is not talking directly to a proxy.

  - Do not try to parse content as markup if we are not going to
    request embedded objects due to non-positive embed_recur.


version 3.1.3
dated 2007-06-13

  - Tolerate binary log "level" statistics with negative mean level
    data, which may be caused by level sum overflow.

  - Fixed --log and --sample_log command-line option descriptions.
    (Mikhail Fedotov).

  - Removed no longer used or maintained nmake-specific Makefiles.


version 3.1.1
dated 2007-03-07

  - Fixed the 'theInOff <= theCapacity' assertion.


version 3.1.0
dated 2007-03-05

  - Support client-side NTLM authentication with proxies.

  - Fixed a bug resulting in a stuck client transaction when the
    HTTP request did not fit into a single I/O.

  - Make GCC4 on Ubuntu6 happier (Mikhail Fedotov).


version 3.0.5
dated 2006-09-25

  - Changed license to Apache v2.0.

  - Support gzip Content-Encoding: Build fails if gzip content
    encoding is requested but an appropriate zlib library is not
    found. Added encoding PGL field to PGL Content type to specify
    supported encodings for a given content type.  Added
    accept_content_encodings field to PGL Robot type to control
    Accept-Encoding request header generation. When parsing
    Content-Encoding values, only gzip encoding is recognized for
    now, and q=0 parameter (if any) is ignored. Generate 406 "Not
    Acceptable" responses and record transaction errors when
    content coding negotiation fails. Send Vary:  Accept-Encoding
    header when multiple codings are possible, depending on client
    acceptance rules.

  - Use autotools to generate Makefiles instead of relying on
    custom generators that are too costly to maintain.

  - Removed licensing terms acknowledgment from ./configure

  - Do not simulate cached DNS responses for embedded objects if
    embedded URL points to a foreign server.

  - Set pipelining depth for each newly opened connection; the
    default is the depth of 1 (i.e., no pipelining)

  - Added initial support for HTTP cookies. Generate cookies based
    on probability, count, and size params supplied by the user
    via PGL (cookie_set_prob, cookie_set_count). Added
    Agent::cookie_sender PGL field to specify sticky probability
    that an agent supports (generates or returns) cookies. Added
    Server::cookie_size PGL field to specify the size distribution
    for generated cookies.  Added Robot::cookie_keep_lmt PGL field
    to control how many cookies (per server) are kept on the
    client side.

  - Added hostedUrls() PGL function to convert a URL trace to an
    array of extracted host addresses.

  - Added pipeline_depth PGL field to control the maximum number
    of concurrent (pipelined) HTTP requests per connection.

  - Allow for more names than there are IP addresses in the PGL
    address map and use round-robin mapping to assign IPs. This is
    needed to support URL traces that may have a lot more real
    host names than the IP addresses the tester is willing to
    create.

  - Support "." or root zone when configuring PGL address maps for
    BIND configuration generation.

  - Disabled recursion in named config file, just in case.

  - When generating a BIND configuration file, comment out records
    for names with underscores: BIND will not use the entire zone
    if it has invalid names.

  - Speedup warmup phase: If we sent two requests to the server,
    the server is considered warmed-up even if there were no
    first-hand responses.

  - Raised log version to 11.

  - Complain if response to a reload request was generated before
    the reload request.

  - Allow content database (cdb) to co-exist with may_contain PGL
    content option and use container information to configure the
    database.

  - Allow the number of embedded objects in a page to exceed 255
    with a slight chance an embedded object ID colliding with
    another object ID. Warn if the number of embedded objects
    increases beyond 500.

  - Added "linkonly" input format to cdb. With this format, cdb
    manipulates embedded URIs (links) as if markup format was used
    but preserves the entire file as a single object as if
    verbatim format was used.

  - Added tagname-independent catch-all rules for common
    attributes such as background and src so that we can find more
    embedded URLs.

  - Presence of the Xact-Id header field is now sufficient for the
    response to be considered as generated by Polygraph.

  - Do not cancel a server-side transaction if the request lacks
    Polygraph headers because it may be a prefetch.  Count such
    requests as errors, for now.

  - When generating IP aliases, avoid interfaces that have no inet
    family information at all (e.g., teql0 on a Linux laptop).
    Thanks to Adrian Chadd.

  - Enabled recovering partial phase statistics from interval
    stats.

  - Deal with duplicate phase names by appending unique suffixes
    instead of crashing.

  - Added page-related stats such as page response time and page
    size.  Page download accounting starts with the first
    "container" transaction and ends with the last transaction
    among those that fetch the container and embedded objects.
    Client-side only.

  - Added a "mean response time versus load" scattered plot figure
    to the report.

  - Added traces of offered and measured hit ratios, based on
    client-side measurements.

  - Report pipelining statistics.

  - Switched to Gnuplot 4.x command conventions. PNG terminal in
    Gnuplot 4.x does not have a 'color' option.  All "set *style"
    commands are now "set style *"

  - Be more robust when reading strings from a corrupted test log.

  - Fixed --unique_world handling when persistent working set
    feature is enabled.

  - Fixed seed generation when computing random request bodies.
    Old generated request content sequences were probably not
    random enough because they were probably always started at the
    beginning of the precomputed random-content source instead of
    starting at random offsets.

  - Fixed handling of timed out DNS queries. The queries were
    probably not retried unless the timeout was reported on the
    console.

  - Content checksums were not generated for some URLs.

  - Newer FreeBSD versions require (/32, /128) netmasks for
    aliases on public interfaces. Warn, but do not quit if the
    explicit mask is too small.

  - The "real." and "cachable."  prefixes of PGL stat objects were
    not recognized. Thanks to Wu S.N.  <wsn@21cncorp.com> (a.k.a.
    Searock)

  - Various GCC3 and GCC4 portability fixes, including the use of
    the newer stringstream interface instead of strstream, to
    avoid "deprecated header" warnings in GCC3 and compilation
    errors in GCC4. The code will no longer work with GCC2 though
    because GCC2 does not support stringstreams.

  - Applied FreeBSD 5.2-CURRENT / gcc-3.3.3 compatibility patches
    from Sergey A. Osokin <osa/at/freebsd.org.ru>

  - Give priority to new <header>s but still load <old.h> headers
    if new headers do not exist. Loading old headers is unlikely
    to help anyway because many interfaces have changed.

  - Fixed network socket handling code on Solaris.


version 2.8.1
dated 2004-10-11

  - GCC 3.4 compatibility fixes
  - GCC 3.3 compatibility fixes backported from Polygraph 3.0
  - guard SIOCGIFINDEX-dependent code (Linux compatibility)
  - String does not have a reset() method
  - include <strstream> as a last resort when compiling string.h
    wrapper; ideally, it too should be guarded by ./configure
  - make sure configure fails if SSL support is not disabled and
    SSL files are not found
  - fixed ReportGen installation, although new reporter should
    be used instead; ReportGen is deprecated and will not be
    available in 3.x


version 2.8.0
dated 2003-11-17

  - SSL/TLS (https) support, including CONNECT requests 
  - HTTP Authentication support, including support for very 
    large user databases (e.g., via LDAP directory) and loadable 
    modules for custom authentication schemes (e.g., RADIUS) 
  - IPv6 support 
  - Automatic adjustment of offered load based on real-time 
    measurements, such as response time or throughput (aka 
    peakfinder or watchdog) 
  - Persistent working set and ability to continue/resume tests 
  - Support for checking decisions of URL- and content-based 
    filtering proxies to allow, deny, or modify content during 
    a performance test 
  - Better integrated, more detailed, and robust result reporter
  - GCC 3.2 support


version 2.7.5
dated 2001-12-31

  - removed "you can modify" clause from the default end-user
    license to comply with University of California license
  - changed default PopModel.bhr_discrimination from 100% to zero
    to remain backward compatible with earlier versions and workloads
    that did not use BHR discrimination algorithm
  - removed "under construction" warnings from -4 workload files
  - log statistics about transactions involving foreign URLs
  - make all accept(2) errors on the server side non-fatal;
    continue to report previously fatal errors
  - make errors when creating a UDP socket to send a DNS query non-fatal
  - report current load factor level when rptmstat is in use
  - better handle very large console messages (some errors may 
    generate output exceeding internal buffer capacity)
  - fixed phase synchronization bug; reordered requests from
    robots could sometimes confuse phase synchronization
    algorithm and lead to incorrect phase schedule 
  - BSDI portability fix
  - fixed lx segmentation fault bug that was especially likely
    in the presence of large number of different errors logged
    during the test
  - do not print millions of "fyi: populus reached max level"
    messages when (often incorrectly configured) test attempts
    to increase the number of robots when all robots are already
    in use
  - fixed other minor bugs that probably remained invisible in 2.7
    branch but were exposed by ongoing code changes


version 2.7.4
dated 2001-09-22

  - synchronized packet delay/loss parameters with on-line
    workloads documentation (PolyMix-4 and WebAxe-4): 40msec delay
    and 0.05% packet loss in both directions, on one side
  - changed plateau phase duration back to 4 hours until more
    evidence is collected to support the theory that shorter
    measurement phase is OK. (WebAxe-4)
  - set final populus factor to zero and added "synchronize =
    false" flag to last phase (dec2) in PolyMix-4 and WebAxe-4
    workloads to ensure smooth test termination
  - do not perform DNS lookups for embedded objects
  - added "synchronize" flag to Phase type (PGL); by default,
    phases try to synchronize their finishes with remote
    schedules; if set to false, the phase will quit when its local
    schedule tells it so; the latter is handy for the very last
    phase of the test when request rate may be almost zero,
    leaving few chances for synchronization; this per-phase flag
    replaces the global --sync_phases option
  - emit progress reports on the console every 5 minutes; handy
    when a phase seem to be stuck for no apparent reason; the
    report frequency is currently hard-coded
  - do not report "premature end of message body" errors when
    transaction is aborted by the other side due to PGL abort_prob
    settings
  - ignore stale objects that became stale while in-transit;
    report more info about stale objects
  - update clock more often at startup
  - replaced several assertions with warnings and workarounds to
    be robust in the presence of yet unknown internal and external
    errors
  - fixed waiting transaction accounting bug: when robots were
    made idle to meet (smaller) populus goal or for other reasons,
    waiting transaction queue was silently flushed instead of
    "killing" each individual queued xaction and updating
    appropriate counters/tables; the bug led to wrong wait.level
    statistics and to memory leaks
  - robot transactions were not resetting calculated Object
    Lifecycle timestamps leading to false "stale object" errors
  - different embedded object IDs were sometimes generated for the
    same container, screwing MD5 checksums and probably some
    supersmart intermediaries because generated content for the
    same oid may not be the same
  - optimized address map searching; linear search was too slow
    for large scale configuration, leading to worse response times
    for servers closer to the end of the robots' origins array
  - make sure that no more than scheduled abort size gets
    written/read on a connection; old code would read/write as
    much as possible, and many scheduled aborts would not happen
    until the object is fully written/read, when it is too late
    for the other side to notice/experience an abort
  - a CRLF sequence was getting appended to a host name in the
    Host: header if that header happened to be the last HTTP
    header in the request/response; Polygraph servers would report
    "foreign host name" errors because of that extra CRLF in the
    host name; other headers in the same [last] position were
    getting extra CRLF as well, but, apparently, their parser
    would ignore those extra characters (or, at least, no
    side-effects were noticed)
  - initialize OS-dependent libraries in aka to prevent aka from
    quitting due to WSAStartup() not being called on MS Windows;
    alias handling code still needs more work on Windows


version 2.7.3
dated 2001-08-30

  - submit requests to foreign URLs if needed; the corresponding
    responses are read but not counted/analyzed as
    hits/misses/etc; the only current valid source of foreign URLs
    are redirect (HTTP 302 Found) responses that have foreign URLs
    in the Location: field
  - use relative URLs in container objects because most embedded
    URLs that point to the same Web site are relative and because
    it solves problems with group of "identical" servers
    implementing one Web site (each server should not put its own
    address into a URL, but should put its visible name, but one
    server may, in theory have multiple visible names)
  - attempt to handle more errors gracefully, without terminating
    a connection and aborting the transaction; still report
    errors as they are detected (polyclt)
  - handle [large] string ranges efficiently (PGL)
  - all open square brackets ('[') in strings must now be escaped
    with a backslash ("\[") for the string to be interpreted as a
    string rather than a range (PGL)
  - compute MD5 checksum for selected objects
  - WSS of 1GB is now required for cache-off entries (WebAxe-4)
  - default port for HTTP surrogates should be 80 (WebAxe-4)
  - client and server-side .hosts values where swapped (WebAxe-4)
  - minimized the number of differences in parameters and layout
    between PolyMix-4 and WebAxe-4
  - added proxy IP:port address to webaxe-4.pg and address map to
    webaxe-4-guts.pg; robots should send requests directly to the
    proxy address as if it were an origin server
  - added port numbers for WebAxe-4 servers (via
    server-side.hosts array)
  - replaced "foreign HTTP request/reply" errors with "foreign
    HTTP request or response" (response without Polygraph-specific
    headers while those headers were expected) and "foreign URL"
    (a URL that does not belong to Polygraph URL space) errors
  - added "foreign URL without host name" error to complain about
    relative foreign URLs when they are not expected
  - warn if popularity model is not set and rep_types are used
    because some reply types require popularity model
  - added X-* extension headers to HTTP 302 responses
  - use WSAEMFILE on W2K instead of EMFILE when indicating
    out-of-sockets condition to make that error reporting on W2K
    work
  - webaxe-4-guts.pg file was not installed on "make install"
  - fixed order-dependency bug in polymix-4-guts.pg and synced
    webaxe-4-guts.pg
  - polished polymix-4-guts file to eliminate non-differences
    with webaxe-4 guts file
  - lx should not read standard input by default
  - fixed yet another bug affecting reported "level" stats; old
    reports could have much higher per-phase level stats than
    what could be inferred from ltrace plots; per-phase level
    stats were incorrect
  - set GET method for redirected requests; old code would assert
    on redirects


version 2.7.2
dated 2001-08-13

  - calculate values for If-Modified-Since header fields using
    Object Life Cycle configuration of the corresponding object
    content type instead of using cached last-modified values;
    robots could not cache enough objects to generate reasonable
    number of IMS requests with "sane" IMS headers; the new method
    solves the problem and eliminates requirement for maintaining
    a private cache on each robot (saving lots of RAM for large
    scale configurations); now we can specify the number of
    IMS-200s and IMS-304s and should be able to meet the specs;
    this is a yet another change that makes it crucial to have
    identical client- and server- side PGL configurations
  - select object birthday as a random point within the object
    life cycle starting at "time zero" instead of allowing
    relative or absolute birthdays; birthday point should not
    matter for any current practical purpose, and having relative
    birthdays made it impossible(?) to re-generate OLC timestamps
    in non-authoritative processes (e.g., clients); the latter was
    needed for robots to generate sane IMS requests; PGL object
    birthday settings are now deprecated and ignored
  - removed private_cache_cap settings (i.e., disabled robots'
    private caches) from all standard workloads; we no longer
    need a private cache to generate IMS requests and, hopefully,
    the latter was the only reason to have it; private caches
    consumed a lot of memory on large scale configurations
  - added "bhr_discrimination" field to the PopModel type to
    control the aggressiveness of the byte hit ratio (BHR)
    discrimination algorithm; 100% makes algorithm the most
    aggressive (default); 0% disables the algorithm; internally,
    bhr_discrimination is actually a probability of applying the
    discrimination algorithm when oid selection is made
  - added bhr_discrimination to generation-4 workloads
  - make request body size of PUT and POST requests random rather
    than 8192 bytes; 8192 bytes is now an upper limit given 16KB
    I/O buffers
  - moved WebAxe-4 details into include/webaxe-4-guts.pg and
    synchronized WebAxe-4 specs with recent PolyMix-4 changes to
    keep the two workloads similar (needs more work)
  - removed "recurrence" field from content types in contents.pg
    since Polygraph does not use it anymore; warn if "recurrence"
    is set
  - increased public_interest from 50% to 75% because we now have
    robots that are not active until after the [private] working
    set size is frozen and, thus, some robots will not be able to
    request objects from their private working set, violating the
    old goal of 50% of request submitted to private subsets;
    while no drastic changes are expected due to this change, we
    need more measurements to understand its effect
  - removed birthday settings from standard OLC configs; OLC now
    ignores birthday settings
  - decreased the ratio of IMS requests in PolyMix-4 from 20% to
    15%
  - configured PolyMix-4 robots and servers to abort 0.1% of
    transactions
  - added 1.5% of POST and 0.1% of HEAD request methods to
    PolyMix-4 and WebAxe-4 workloads
  - added zone name back to AddrMap in PolyMix-4; dns_cfg should
    work with polymix-4.pg now
  - increased supported and required log version to 10 due to
    transaction logging changes; older logs cannot be read with newer
    readers and vice-versa
  - IpsToNames() now preserves port numbers (PGL)
  - supply more information about DNS timeout errors
  - DNS answers were allocated but not freed, leaking a memory on
    every DNS request
  - try other DNS servers (if any) when DNS query times out
  - cloned addresses are now iterated depth first when agent
    aliases are created, because alias creation code tries to
    allocate n-th chunk of addresses rather than every k
    addresses; the old code would create twice as many aliases for
    addressing schemes with more than one agent per address; the
    new code creates the same alias twice; needs more work to
    avoid extra creation
  - "--names" option was treated as "--addresses" option (dns_cfg)
  - improved old IP alias deletion on OSes with numbered virtual
    interfaces (e.f., Linux and Solaris); this needs more work;
    for example, one cannot have both polyclt and polysrv creating
    aliases on the same Linux box
  - fixed netmasks and broadcast address settings on systems with
    "numbered" virtual interfaces and without ifaliasreq structure
    (e.g., Linux and Solaris); old code did not set netmasks and
    broadcast addresses at all (effectively), and defaults were
    probably assigned by OS
  - when creating aliases, we were opening a new socket instead of
    closing an old one, creating thousands of "extra" sockets when
    aliases were created on a box; this led to "too many open
    files" errors on some systems, at least


version 2.7.1
dated 2001-08-03

  - added "recurrence" field to PGL's Content type; recurrence
    value affects the probability of the content type being
    selected when Polygraph decides which object should be
    revisited among a set of candidates; recurrence is a "weight"
    rather than "probability" because several objects of the same
    type may be present in the selection group and the sum of all
    weights can exceed 1.0; in other words, the selection group is
    formed first, recurrence weights are applied second;
    recurrence weight defaults to 1.00
  - added "zone" field to AddrMap type (PGL); the zone name is
    not used by Polygraph run-time, but can be used by external
    programs such as dns_cfg to build zone files based on PGL
    configuration
  - added ipsToNames() PGL function to convert an array of IP
    addresses into host names using a simple 1:1 mapping
  - added "--config" and "--cfg_dirs" options to dns_cfg to
    extract required information from a PGL file; old
    command-line options interface is still supported and is
    mutually exclusive with the new PGL interface
  - added DNS resolver address as a parameter for PolyMix-4
    workload; set DNS resolver timeout to 5 seconds
  - use ipsToNames() to generate DNS names for PolyMix-4 servers
    PolyMix-4 workloads are now using DNS names; this can be
    disabled (in violation of PolyMix-4 rules) by setting AddrMap
    "names" to server "addresses"
  - polished PolyMix-4 workload files to explicitly list address
    space and real hosts settings; /22 subnet must be specified
    for address space or PGL will compute the smallest subnet
    given the bench configuration (smaller subnet will lead to a
    different agent addresses compared to the required /22 subnet,
    screwing up routing)
  - added recurrence weights to content types used in PolyMix-4;
    this should improve byte hit ratio (BHR) simulation, but it
    looks like more work is needed to actually make that happen
  - polished dns_cfg output to better match BIND files format
  - renamed "--domain" to "--zone" (dns_cfg)
  - renamed Session's heartbit_notif_rate to heartbeat_notif_rate
    (PGL)
  - reduce the number of "labeled logs have no object named X"
    messages when generating reports
  - account for the number of agents per address when computing
    minimum (smallest) subnet in version-4 addressing schemes;
    old code incorrectly complained about /22 being too small for
    PolyMix-4 workloads because it did not account for the fact
    that two PolyMix-4 robots may share an IP address
  - plot_traces was using unportable regular expression feature
    that led to "Character class syntax [: :] is reserved for
    future extensions" Perl errors when generating reports; use a
    more portable expression instead
  - delete old IP aliases before creating new ones; old code
    was not calling the delete method


version 2.7.0
dated 2001-07-29

  - added "req_methods" field to Robot (PGL) to specify
    distribution of HTTP request methods for a robot to use;
    supported methods are GET, HEAD, POST, and PUT; methods that
    allow request bodies (POST and PUT) use constant body size of
    8192Bytes, for now.

  - added "abort_prob" field to robot and server PGL
    configurations to abort transactions based on on a given abort
    probability; robots may abort while receiving response body,
    and no aborts while sending headers, waiting for a response,
    or reading response headers are supported; servers may abort
    while sending response body, and no aborts while sending
    headers, waiting for a request, or reading request headers are
    supported

  - added "addr_space" field that deprecates "addr_mask" field;
    version-4 addressing schemes use "addr_space" addresses to
    generate robot and server addresses; older schemes used only
    two first octets of, now deprecated, addr_mask, making agent
    address configuration too rigid; "addr_space" can list any IP
    addresses as long as they comply with the addressing schemes
    in use; this is a big change so there may be bugs in
    implementations of addressing schemes that now use addr_space

  - rewrote PGL arrays to allow array members to be arrays; the
    nesting is almost transparent to the end-user as far as member
    iteration is concerned (i.e., nested arrays are flattened
    automagically), but does affect probabilities assignment
    because each container can have its own [sub-]probabilities in
    addition to a member probability specified in the array;
    doing something like "[ a: 5%, [b: 10%, c]: 50%, d]" is now
    possible and equivalent to "[a: 5%, b: 5%, c: 45%, d]"

  - added a binary "+" operator for arrays so that two arrays
    can be concatenated without nesting

  - added "--delete_old_addrs <bool>" option to polyclt/srv to
    specify whether old IP addresses should be deleted when
    creating new IP addresses; defaults to "yes"; may allow to
    run polyclt on the same box as polysrv _and_ create aliases
    run-time (bit more work would be needed for OSes that number
    their alias interfaces for system call purposes)

  - do not send Last-Modified and Expires headers for uncachable
    objects; some proxies (e.g., Apache's mod_proxy 1.3)
    completely ignore "Cache-control no-=cache,private" and
    "Pragma: no-cache" response headers and cache an object if
    a response has, say, a valid Last-Modified header

  - use interface names and subnets directly from agent.addresses
    arrays instead of addr_mask when creating new aliases; now, in
    theory, one can have agents bound to several interfaces and
    still be able to create aliases automatically

  - added PolyMix-4 workload (first draft) and 
    synchronized them with PGL changes

  - use 2 robots per IP for WebAxe-4 and PolyMix-4; this allows to
    support higher request rates with reasonable number of IP
    aliases

  - bumped log version to 9 due to new stats (HEAD/POST/PUT and
    aborts) being logged

  - reduced memory footprint of large address ranges and large
    "**" clones (PGL)

  - renamed option "--addrs" to "--addresses" (dns_cfg)

  - "something/0" expressions were interpreted as rate because
    zero is convertible to time (e.g., 0 seconds); forced PGL to
    just complain about division by zero instead


version 2.6.5
dated 2001-07-29

  - use "binary" mode for log files; required on MS Windows for
    the logging to work; previous versions produced corrupted
    log files on MS Windows or any platform that treats binary
    files specially
  - changed Unix makefiles to stop after the first error


version 2.6.4
dated 2001-07-09

  - added "proxies" field to robot PGL configuration; proxies
    must not be used together with the --proxy command line
    option as they are mutually exclusive; a robot selects a
    random proxy at the configuration time and uses that proxy
    for the entire duration of the test (sticky proxy
    assignment); proxy addresses are distributed evenly (if
    possible) among all robots in the test; individual groups of
    robots (e.g., all robots on one host) may not get an even
    distribution.
  - support "make install" in workload files; "make install"
    will overwrite existing files in the destination directory
    (/usr/local/polygraph/workloads by default); users are not
    supposed to modify original workload files and should
    create copies when modifications are needed
  - made aka robust when no primary IP is present on the interface
  - lognormal mean and standard deviation were not reported
    correctly (Johnson Lee <jl03@gte.com>)
  - synced comments in polymix-3.pg with Bench type changes
  - clientHostCount in PolyMix-3 on 2.6 branch was not computed
    correctly, leading to ridiculously small working set sizes
    and shorter fill phases


version 2.6.3
dated 2001-06-27

  - emit (errUnreachContType) "unreachable content type" when an
    embedded content type cannot be found on the [visible] server that
    hosts the container object; Polygraph can only handle embedded
    objects that reside on the same visible server as the container
  - use the same content distribution for all L7 servers (except
    for the URL extension) so that all servers will get similar
    load
  - when server's direct_access probabilities are specified manually,
    use them and do not compute our own
  - added "byte.rptm.mean", [milliseconds / kilobyte] object to Report
    Generator. The object value is visible in make_report as "byte"
    table entry in the Response Time table and as the byte_rptms plot.
  - replaced --rng_seed option with two new options:  --global_rng_seed
    and --local_rnd_seed. Both default to 1.  All processes within a
    test must have the same --global_rng_seed value to correctly
    generate "global" information such as a URL extension for the same
    object ID.  All processes within a test should have different
    --local_rnd_seed settings to avoid lock-step behavior of things that
    should not be synchronized.
  - do not print "Potential problems" header if no problems are detected
    by make_report
  - when generating a public miss, use local public world slice
    only; using remote slices creates race condition for
    generating a miss with the corresponding remote agent; these
    race conditions lead to buggy offered hit ratio
  - W2K select(2) fails if no FDs are passed to it (i.e., all FDs sets
    are empty)
  - fixed fixed a very old bug (again) that, under certain conditions,
    left some FDs ignored by select(2); the earlier fix was ineffective
  - fixed ceil() workaround once again: the earlier fix was ineffective


version 2.6.2
dated 2001-06-13

  - polished SrvLB workloads; added SrvLb4As addressing scheme;
    same as WebAxe4 but uses server_side.hosts for server
    addresses instead of building them using a
    server_side.addr_mask
  - try to select appropriate target if content type is known so
    that embedded objects will be directed to the right targets;
    this feature is needed for L7 SLB tests; needs more work to
    randomize target selection when more than one target server
    has the required content type
  - if no command is given to forsome, just print addresses in the
    specified host group
  - check that the content type in the request URI belongs to the
    server that the request was sent to; generate a misdirected
    request error if it does not; previously, a server would
    happily serve any content type that belonged to at least one
    server in a PGL configuration
  - open DNS/UDP socket for a robot only when the first DNS query
    needs to be sent out; this will prevent polyclt from creating
    one socket for every robot even when no DNS queries are
    needed; also do not select(2) DNS/UDP socket for reading when
    there are no pending transactions to reduce CPU overhead when
    some DNS queries are present
  - public URL worlds were erroneously updated with stale data
    when hot set position of the stale snapshot differed from the
    current one; the bug led to incorrect (higher than what should
    have been offered) offered hit ratios
  - fixed a very old bug that, under certain conditions, left some
    FDs ignored by select(2)/poll(2); most likely, the bug was
    never or infrequently triggered by Polygraph code before;
    noticed the bug when adding BEEP support that has somewhat
    different FD registration/scanning pattern from the rest of
    the code.
  - libc's ceil(700/0.7) returns 1001; the old workaround was not
    good enough, and led to creation of 1001 agents where only
    1000 agents were needed; added a better workaround
  - made interface aliases / primary address detection code more
    robust on Linux
  - changed recur_factor to recur_factor_{beg,end} in webaxe-1.pg


version 2.6.1
dated 2001-06-05

  - fixed "version three" addressing scheme bug that led to incorrect
    addresses being auto-generated for PolyMix-3 and other -3 workloads
    that used addressing scheme PGL feature
  - a server now checks for requested URL to belong to that server; if
    request is misdirected, the connection is closed with an xaction
    error message dumped to the console; no 404 HTTP error is generated
    at this time
  - added --load_balancer option to make_report to generate slightly
    different reports for load balancing tests


version 2.6.0
dated 2001-05-22

  - changed licensing terms and added not-for-publication clause
  - updated README
  - added DNS/FQDN client-side support; robots can now send
    [non-blocking asynchronous] DNS queries to specified DNS servers to
    resolve destination addresses; DNS responses are currently not
    cached
  - added pxylb-4.pg and srvlb-l4-4.pg workload drafts to test proxy
    and origin server load balancing, respectfully
  - added webaxe-3.pg configuration file for WebAxe workload; this
    file was distributed with Polygraph version 2.5.4 under the name
    webaxe-2.5.pg
  - create IP aliases upon startup, based on the PGL bench
    configuration; warn if aliases are not being created and explain
    why
  - log PGL configuration upon startup
  - added support for URL prefixes; arbitrary string(s) can be
    specified to be included as a URL "prefix", right after the first
    '/' following the host name or host address; use Mime.prefixes for
    now (just like Mime.extensions)
  - added "special_msg_factor_beg" and "special_msg_factor_end" fields
    to Phase specs to control the presence of special messages (IMS,
    Reload, 302 Found, etc.) in the generated stream (PGL); useful to
    speedup fill phase and to test the influence of those special
    requests on the cache
  - handle ``302 Found'' replies: treat them as special valid kind of
    an HTTP response and follow URIs in the Location: field; 302s may
    be foreign replies, but 302 takes priority when it comes to
    redirection handling and statistics logging
  - added client-side support for HTTP 300, 303, and 307 responses; a
    Robot would request the Uri found in the Location: field of the
    response after processing the original transaction
  - use new client-centric PubWorld interface instead of old
    server-centric object ID (oid) exchange; use/maintain related
    global indexes; broadcast/update PubWorld info
  - added support to flip-flop debugging (--dump hdrs) status on USR1
    signal
  - try to flush logs when process is running out of memory;
    pre-allocate a 16KB buffer to be freed when we are running out of
    memory, in hope to get enough memory to flush the logs; this trick
    may help to save some of the logs when Polygraph quits with
    "virtual memory exhausted in new"; may need more work
  - added phase name reporting to ltrace; when multiple logs with
    different phases are merged, the printed phase name can be the
    name of any then-current phase.
  - added polyprobe -- a traffic-volume-oriented network test tool
    that will, eventually, replace netperf for many-to-many raw
    network bandwidth tests used before PolyMix tests
  - added polyrrd tool to supply run-time Polygraph stats to the rrd
    tool; rrd tool is a "better MRTG" software for displaying run-time
    stats in graphical form:
    http://ee-staff.ethz.ch/~oetiker/webtools/rrdtool/
  - added rrd-cgi.sh as a sample file to use with polyrrd and rrd tool
  - pgl_test now accepts include directories as parameters (after the
    PGL file to test)
  - assume URLs starting with "/health" are health checks and reply as
    if --ignore_urls was set
  - added "Rptmstat" PGL type to store response-time-stat (as in
    thermo-stat) configuration; a rptmstat attempts to keep response
    time within the specified bounds by adjusting offered request rate
    (just as a thermostat attempts to keep temperature within the
    specified bounds by adjusting the furnace or A/C operation)
  - added "rptmstat" field to Phase type; rptmstats are activated on a
    per-phase basis
  - added "rep_types" field to Server agent type (PGL); "Basic" and
    "302 Found" reply types are supported
  - added "client.hosts" and "server.hosts" fields to Bench object to
    specify real machine addresses (as opposed to "virtual" aliases for
    agents) (PGL);
  - added DnsResolver PGL type to configure DNS resolver for robots
  - skip insane/corrupted entries in the trace and warn about them;
    trace corruption may happen when Polygraph process or the host OS
    is killed without a chance to flush the binary logs
  - added dns_resolver field to Robot type
  - support port ranges in PGL addresses
  - added use(Bench) PGL call to specify the bench configuration for
    the test
  - added minimize_new_conn field to Robot to specify probability of
    an attempt to use idle connections to address' substitutes when no
    idle connections to the address are available; added
    note_substitutes() procedure call to register known substitute
    groups (PGL); substitutes are useful to approximate connection
    reuse pattern of a single-destination workload in a no-proxy or
    no-balancer setup
  - added dns_cfg tool to generate configuration files for named, a
    DNS server, needs more work
  - use a new tool to generate Makefiles for Unix (gmake) and MS
    Windows (nmake). Temporary lost ability to built out of the source
    directory.
  - renamed --*log_size to --*log_buf_size so better reflect the true
    meaning of the option
  - removed the --new_oids* options as unused
  - renamed popularity distributions pmUnif and pmZipf to popUnif and
    popZipf to avoid conflict with popularity models (pm*)
  - polished simple.pg and moved simple server to port 9090 to avoid
    strange port 8080 hijacking problems on some Windows installations
  - synced standard workloads with PGL changes
  - changed HotSet algorithm to avoid storing theObjLmt: change hot
    position when it is no longer in the working set; when WSS is
    unknown, keep hot position in the middle of the URL set
    (constantly sliding position); the rationale is to reduce memory
    overhead and, maybe, to simplify remote synchronization of hot
    positions
  - changed Bench definition to use BenchSides instead of client_ and
    server_ prefixes
  - added new "Addressing Scheme" PGL types to calculate agent
    addresses for various workloads
  - PGL agents should always bind(2) to specified addresses
  - removed "Rptm vs Size" and "Conn Life Time vs Use Count"
    statistics; (they were huge and rarely used; similar data can
    probably be derived from stats samples)
  - changed binary log format and version
  - moved pop_model PGL field from Robot to Agent because Server agent
    needs it to generate ``302 Found'' responses
  - replaced "agent.hosts" fields with "agent.addresses" to be more
    consistent; "hosts" in PGL usually means "real, permanent
    address" while "addresses" are often used for IP aliases that are
    created run-time
  - use address ranges when printing arrays of addresses, if possible
  - when checking for "clocks out of sync" errors, ignore replies that
    took a long time; slow replies is usually an indication of
    problems other/bigger than clock synchronization
  - embedded objects should inherit request type property from the
    container (not ideal, but better than using default req type for
    all embedded objects)
  - removed old place() PGL function
  - increased client-group-count-dependent hash capacities from 11 to
    37 old limits did not allow to use more than 11 clients or server
    machines in a test
  - changed default value of polysrv's --idle_tout to 5 minutes
  - removed piper tool -- it was not used and caused compilation
    problems on FreeBSD 4.x due to new DummyNet interface
  - tried to make alias manipulation with aka work again on Linux
  - added port of msl_test to linux, based, in part, on code donated
    by Andrew Schultz from Mission Critical Linux, Inc. More work is
    required to make msl_test more portable
  - provide traces of conn.open.rate and conn.estb.rate in the report
  - improved report generation tools
  - AIX portability fixes
  - HP-UX (aCC) portability fixes
  - Linux portability fixes
  - MS W2K (VC++) portability fixes
  - Solaris portability fixes
  - added config.bat script to compile sources with nmake on Windows
  - reduce default optimization level on Linux to 1 (-O1) to avoid
    coredumps
  - lots of polypxy fixes to make it more robust; needs more work
  - a yet another attempt to fix code that merges level stats
  - adjusted alias creation code to extract and honor individual
    subnets of the alias addresses
  - when merging (not concatenating) stats, the duration should be set
    to the maximum duration of the two intervals being merged so that
    merging 10 req/sec for 1 sec and 1 req/sec for 1 hour does not
    result in 11 req/sec mean; will this screw anything that used to
    work?
  - when merging or concatenating phase stats, do not change the phase
    name if phases with the same are joined
  - fixed ./CdbBodyIter.cc:43: assertion failed: '!theInjector';
    a common problem with realistic content simulation module
  - fixed an old ltrace bug: sampling windows were sometimes getting
    huge, leading to excessive memory consumption and possibly somewhat
    incorrect trace plots
  - "ceil(700/0.7)" returns 1001(!!); added a workaround; old IP
    calculation tools were generating wrong values when 700
    req/sec/host and 0.7req/sec/agent combination was used
  - aka was not setting subnets right


version 2.5.5
dated 2001-05-01

  - updated copyright/license statements
  - added licensing terms acknowledgment to ./configure script
  - resurrected support for user-defined or "table-based" distributions;
    e.g., ``SimpleContent.size = table("/tmp/t.distr", "size");'' where
    /tmp/t.distr contains the distribution of type size_distr
  - added webaxe-3.pg configuration file for WebAxe workload; this file
    was distributed with Polygraph version 2.5.4 under the name
    webaxe-2.5.pg
  - Red Hat 7.0 compatibility fixes
  - AIX compatibility fixes
  - fixes for platforms with unsigned chars (e.g. AIX); PGL parser would
    quit on those platforms with error location pointing to the end of a
    file being parsed
  - fixed an old ltrace bug: sampling windows were sometimes getting
    huge, leading to excessive memory consumption and possibly somewhat
    incorrect trace plots
  - fixed local time detection bug on Solaris; the bug caused Polygraph
    to complain about client/server clocks being out of sync even if
    both processes were running on the same host
  - replaced "MB/sec" column heading produced by make_report 
    with less confusing Mbit/sec


version 2.5.4
dated 2000-07-24

  - added "special_req_factor_beg" and "special_req_factor_end"
    fields to Phase specs to control the presence of special
    requests (IMS, Reload, etc.) in the generated stream (PGL)
  - identify cases when HTTP race conditions lead to connectivity
    errors on used-to-idle persistent connections; retry
    transactions when such errors occur; log the number of retried
    transactions (that otherwise do not affect statistics)
  - eliminated most of the special (non-Basic) requests during the
    fill to shorten the fill phase (PolyMix-3)
  - when a phase meets its goal, wait until all remote phases are
    ready before proceeding
  - added the "--sync_phases <bool>" option to disable auto phase
    synchronization if needed
  - log statistics about oid generation algorithm
  - distinguish "hot" requests in stats samples
  - polished stats samples and made them smaller
  - report WSS in terms of bytes (in addition to object count); be
    careful when interpreting the values -- adjust for embedded
    objects and other hosts in the bench
  - complain if server agent port is not specified
  - upgraded current and required log versions from 2 to 3; log
    versions were not upgraded for a while despite format changes,
    unfortunately
  - warn about log extractor <--> log producer versions mismatch
    when reading a log
  - fixed typo in X-Srv-Sets header parsing code that led to
    growing WSS for public (shared) objects, resulting in
    lower-than-expected HR
  - fixed ./CdbBodyIter.cc:43: assertion failed: '!theInjector'
  - fixed coredumps when all configured phases are ended and
    Polygraph adds a "cold" phase for the last transactions to
    finish and coredumpts with segmentation fault
  - made reportgen.cfg dependent on ./configure parameters


version 2.5.3
dated 2000-07-19

  - ProxyCacheSize in polymix-3.pg should now be set to the
    *total* proxy cache size, without adjusting for the number of
    polyclt processes; all adjustments are now done in
    polymix-3-guts.pg, without user participation (the patch
    with the above functionality was posted shortly after 2.5.2
    was released)
  - added the clientHostCount() function to compute the number of
    client hosts based on the PolyMix-3 rules (PGL)
  - added client_host_count to benchPolyMix3; if not defined by
    the user, its value will be computed on-the-fly in
    polymix-3-guts.pg:  TheBench.client_host_count will be set to
    clientHostCount(TheBench)
  - added the "fexit" phase to PolyMix-3; fexit increases hit
    ratio to peak level while decreasing request rate; this phase
    may be required for proxies that get overwhelmed by high loads
    with low hit ratio; the latter were possible during "inc1"
    when hit ratio was increased along with request rate, but not
    "fast enough".
  - adjust Robot's recurrence ratio for Reload requests (we are still
    unsure what to do with IMSes)
  - collect small transaction sample during the fill phase (PolyMix-3)
  - polypxy can now handle misses (not yet robust in error-rich
    environments)
  - a Robot that did not request any private objects from a server
    before WSS was frozen should try not to request new private
    oids from that server; doing otherwise populates the working
    set with oids that cannot be requested again in the future
    (because the corresponding WSS is zero) but may consume cache
    space, etc.  Generating a new private oid is always the last
    resort, but it should not be the second best choice.
  - hot set objects may have been sometimes chosen outside of the
    working set, leading to false false hits and lower hit ratio;
    other objects may have been subjected to this as well
  - request embedded objects during the initial server scan (not
    requesting them makes Polygraph think that an embedded object
    was requested before when it was not, decreasing HR)
  - made polymon report Network Bandwidth usage again (untested)
  - moved foreign request error reporting so that we still have
    request headers to dump
  - marking a freshly accepted socket as a non-blocking or
    not-naggling socket may fail when poly* is overloaded; do not
    exit the program but rather continue after reporting the error
  - fixed two coredump-inducing bugs in the polypxy module
  - aka was exiting silently when no "anonymous" options where
    specified
  - support the "log_dir" option to label_results


version 2.5.2
dated 2000-07-13

  - accept more than one alias range (aka); useful for running
    robots and servers on the same machine (but do not do that for
    production tests!)
  - do not attempt to extract the broadcast address of the
    interface, we do not need it and some interfaces (e.g., lo0 on
    FreeBSD) may not have one (aka)
  - added tools/pmix3-ips.pl script which is identical to
    pmix2-ips.pl except that it also prints IP ranges for each
    host in the bench (in default, verbose mode)
  - added IMS/reload statistics collection and reporting IMS and
    reload transactions are now treated separately from "basic"
    transactions and do not affect hit ratios, fill rates and
    other statistics that is hard to define for IMS and reloads
    (e.g., what IMS response can be count as a hit?); The
    "Contribution" table in generated reports needs more work as it
    is not 100% in sync with the above change
  - added working_set_cap() function to freeze WSS based on the
    number of transactions rather than run time (PGL)
  - added min() and max() functions to PGL
  - split polymix-3.pg into [modifiable] polymix-3.pg and
    [read-only] include/polymix-3-guts.pg
  - specify WSS in terms of fill responses rather than time (the
    calculation is still time-based, just like in Polymix-2); WSS
    is meant to be equal to 4 hours of fill traffic during a "top"
    phase, approximately (polymix-3.pg)
  - specify ramp durations as a fraction of plateau durations to
    ease scaling of a test (polymix-3.pg)
  - added "wait_wss_freeze" boolean field to PGL's Phase; if set,
    the phase will finish only if the working set size is frozen
    (and all other goals are satisfied, of course)
  - make sure that fill phase stops only if working set is frozen
  - do not request embedded objects while in the initial
    server-scan mode
  - shortened launch window because we no longer request embedded
    objects
  - decreased warmup phase goal to a single launch window
  - detect malformed HTTP request or response lines and complain
  - check that embedded object type makes sense and complain if it
    does not (instead of dumping core)
  - Polygraph was erroneously reporting "hit on reload requests"
    for some embedded objects
  - removed "http." prefix from some lx object names
  - report the number of local private objects in the working set
    size
  - obey RFC 2616: do not send any extension-headers with 304s
  - Zip files should have ".zip" extension, not "zip"
    (contents.pg)
  - yet another attempt to make oid exchange algorithm more robust
    (needs more work)
  - increased new_oids_history default to from 1024 to 2*1024
  - increased new_oids_prefetch default to from 128 to 256


version 2.5.1
dated 2000-06-26

  - added support for realistic HTML simulation
  - added aka support for IP alias manipulation on systems that
    use virtual interfaces such as eth0:1, including Solaris
    (untested) and Linux (tested)
  - polished the code that searches for local interface addresses
    in hope to make it work on more OSes
  - added robotAddrs() and serverAddrs() functions: PGL now knows
    how to compute PolyMix-2,3 IP addresses, given the peak
    request rate (and other parameters); make use of that feature
    so that people do not have to spell out IP addresses in
    polymix-3.pg; explicit addresses are still supported, of
    course; IP aliases still need to be created before the test
  - added "Bench" type to describe parameters for the IP
    allocation schemes and include/benches.pg to describe standard
    IP allocation schemes
  - support variable recurrence ratio: replaced "recur_factor" in
    Robot with recur_factor_beg / recur_factor_end pair for smooth
    change in recurrence ratio (PGL)
  - polished definitions of fill-related phases to make use of
    variable recurrence in PolyMix-3
  - polished launch window calculations in PolyMix-3 (needs more
    work)
  - added the "--ign_bad_cont_tags" option to ignore content tags
    that a Robot cannot parse; useful with realistic HTML
    simulation
  - added the "--ign_urls" option to generate content regardless
    of the URL being requested; useful when running polysrv in a
    "demo" mode
  - fixed logging of ICP statistics
  - added reporting of ICP measurements to the Report Generator;
    the above reporting is enabled only when ICP stats are present
    in the logs
  - make sure IMS timestamp is always at least 00:00:00 UTC,
    January 1, 1970
  - fixed type unification compile-time bugs
  - Solaris portability fixes (IP aliasing improvements are
    untested due to the lack of root access to a Solaris box)
  - "everything expires when modified" should use "nmt" not "lmt"
    in olcStatic in contents.pg
  - replaced pop_model settings to make old workloads "compile"
    with new PopModel type (PGL)
  - support number/rate operation (returns time) (PGL)


version 2.2.9
dated 2000-01-13

  - added downtime-2.pg workload specs for the "power-off" test
  - when transaction fails, it may take a while for polysrv to
    stop waiting on the corresponding object id; the latter may
    lead to a situation when hits are generated only using oids
    that are smaller than the lost oid, preventing WSS algorithm
    from "sliding"; we now attempt to report "lost" oids back to
    the server so it does not wait for them; the latter may
    improve hit ratio for "small" caches in the presence of
    errors
  - freeze WSS based on last object id sent to the server rather
    than last object id confirmed by the server (to prevent
    funny tiny working sets in the presence of errors when oids
    may get lost)
  - groups with working set size of zero were not handled
    correctly; a group has zero size if it was never used prior
    to the working set freezing time
  - on the client side, distinguish closed connection with no
    headers sent from a closed connection with some headers
    sent; that is, distinguish "connection closed before sending
    headers" from "premature end of msg headers"; the former may
    by due to HTTP race condition, the latter is definitely a
    bug.
  - added "Errors Total Count x 1000" screen to polymon
  - assume BB/*.pm files are in /usr/local/polygraph/BB or in
    the current dir
  - polished bb.pl output
  - added tools/pmix2-ips.pl and tool/BB/forsome scripts that
    help in configuring and running [large scale] experiments
  - removed most defaults values for options of Report Generator
    tools; reportgen.cfg should be used instead; needs more work
  - allow up to 0.1% difference between fill count measured and
    computed based on hit and cachability ratios (Report
    Generator)
  - do not complain about too many waiting requests because it
    is not clear what "too many" is (Report Generator)
  - plot cachability ratio along with hit ratios (Report
    Generator)
  - ported Report Generator to Solaris (the patch was available
    for 2.2.8)
  - do not dump core if a requested phase is not found in the
    log (lx)
  - do not quit on logs with [very] different absolute times
    (ltrace)
  - made log merging algorithm less susceptible to minor local
    time differences between machines where the logs where
    generated (lx, ltrace); "level" traces (e.g., those produced
    by Report Generator) no longer have weird slight downward
    slopes
  - statistics about "waiting" (queued for connections)
    transactions was not collected appropriately resulting in
    zero readings
  - fixed "request rate for robot X is not positive"
    configuration time bug (the patch was available for 2.2.8)
  - compile IpSocket.cc even when IPFW is not supported (the
    patch was available for 2.2.8)
  - prevent "invalid type X for default argument to Y"
    compilation errors


version 2.2.8
dated 1999-12-27

  - added "req_inter_arrival" field to Robot to specify other
    than Poisson inter-arrival time distributions; for example,
    downtime test will use constant distribution (PGL)
  - redesigned lx to concentrate on phase-related statistics and
    support multiple log files; phases with equal names are
    merged, and phases with different names are concatenated to
    produce correct "totals"
  - added `ltrace', a tool to generate traces based on binary
    logs; this functionality was moved from `lx' that no longer
    supports trace extraction
  - changed naming scheme for log objects to be more consistent
    and scalable, added a few new objects
  - log statistics about transactions waiting for resources to
    become available (e.g., requests waiting for a robot
    connection pool to allocate a connection); this changed log
    format, unfortunately
  - dump more information on "foreign content <tag>" and
    "malformed content <tag>" errors
  - added a cool "summary" screen to polymon
  - do not quit when all phases met their goals when there is a
    positive idle timeout; wait for that timeout to expire (so
    that servers do not quit while clients are running)
  - do not log ascii representation of addresses when storing
    current state
  - "level" statistics was not maintained properly between
    phases
  - "fill" stream was measured as "miss" stream instead of
    "cachable miss"; polyfill-2.pg was not affected because all
    polyfill objects were cachable
  - gettimeofday(2) system call is broken on FreeBSD; make sure
    internal Polygraph clocks never go backwards and show sane
    values
  - avoid infinite recursion coredumps when we fail to write a
    log entry; report and try to salvage logging errors instead
  - do not dump core if a phase has no name, use "" name instead


version 2.2.7
dated 1999-12-15

  - added "--time_scale" option to lx; positive values make lx to
    print relative [to the run start] time for traces, scaled by the
    specified amount
  - added "Traces" macro to represent all "traceable" objects in lx
  - added rptm_mean:hit and rptm_mean:miss to lx's All micro
  - only redirect standard output when --out option is used (lx); used
    to redirect error streams as well
  - try to skip corrupted entries in [otherwise valid] binary logs
  - implementation of lognormal distribution used incorrect standard
    deviation leading to occasional huge objects and
    smaller-than-configured means
  - changed content sizes for cntOther and cntDownload after fixing
    the lognormal distribution bug to get the right mean object size
  - removed percents from Server.direct_access specs; those values are
    ignored by Polygraph because servers calculate them from scratch
    to match "global" content distribution
  - the sum of squared values was not computed correctly leading to
    incorrect readings for standard and relative deviations for
    samples with sampled values larger than 46341


version 2.2.6
dated 1999-12-07

  - PolyMix-2 workload now uses 0.4/sec per-robot request rate; use
    cloning or IP aliases to get more robots (and hence higher
    request rates)
  - added "rep_sz_mean" object to lx
  - added polyfill-2.pg to workloads/
  - added pmix2 blob to tools/BB/bb.pl and polished bb.pl's comments
  - when using --dump, dump transaction meta-info even if there is
    no message data to dump
  - recognize KB scale for command line size options
  - two meant-to-be-independent random number generators used for
    simulating object sizes got "in-sync", producing wrong size
    distributions
  - phases with decreasing request rate were dropping request rate
    too fast
  - public_interest for PolyMix-1 and DataComm-1 workloads should be
    set to 0%, not 50%.
  - added now-required hit ratio and popularity model specs to
    datacomm-1.pg
  - avoid division by zero on corrupted log files


version 2.2.5
dated 1999-11-29

  - added "idle_pconn_tout" field to Agent to specify the maximum
    time an idle (no pending transactions) persistent connection
    should remain open (PGL)
  - support phase-dependent recurrence ratio; useful for populating
    the cache (fast, with only a few hits) and then doing
    measurement phase with appropriate hit ratio, all in one run
  - added "recur_factor" field to Phase (PGL)
  - added support for priority scheduling: Polygraph runs (N-1) file
    scans for file descriptors (connections) that require urgent
    action and then one scan for all file descriptors; N is
    configurable using the --priority_sched option
  - added "--priority_sched" option to control priority level for
    somewhat urgent socket I/O operations; giving higher priority to
    some operations may improve performance in environments with
    lots of probably idle connections as Polygraph will spend less
    time processing those connections; "over-optimized" setting are
    likely to cause noticeable increase in response time; the
    default priority is 5; to disable the optimization, set to 1
  - added support for assigning the same value to several variables
    with one assignment operator (PGL): [ a1, a2, a3 ] = 100%;
  - added support for randomly distributing values of an array among
    several arrays, each with an optional "portion" quantifier; for
    example:
          [ arr1 : 60%, arr2 : 20%, arr3 ] = '10.0.1.1-255';
    this feature is very convenient when distributing network
    addresses among several objects (e.g., servers or pipes) (PGL)
  - grow storage area for new oids when clients start to run out of
    them (to make prefetching more aggressive)
  - optimized initial server scan (when robots are "touching" all
    servers to make sure robots can later generate hits on every
    server); the scan is now much faster and has more random access
    pattern
  - added reporting of server scan progress
  - "lock" first phase until all robots are ready to hit all servers
  - when an advertised oid has not been requested for a while, see
    if we should grow the bitmap to store more oids (and hence keep
    an oid for a longer time) instead of reclaiming that stuck oid
  - changed default for "--new_oids_prefetch" from 256 to 128
    because Polygraph is not capable of dynamically adjusting
    prefetch amount
  - if load factor reaches zero, stop submitting requests
  - check for late alarms and other timers and report if we are
    getting behind the schedule
  - server now accepts new connections for at most 10msec at a time
  - do not quit when running out of file descriptors in accept()
    call
  - destroy PGL objects after use to reduce memory footprint for
    large scale configurations
  - use idle_pconn_tout of 15 seconds for PolyMix-2 servers
  - changed Robot.open_conn_lmt to 4 in polymix-2.pg
  - polished phase definitions in polymix-2.pg
  - check for error status when deleting rules and pipes (piper)
  - re-ordered screens in polymon
  - resurrected err_cnt_tbl in lx
  - the "--phase" option was not supported for non-traceable objects
    (lx)
  - fixed introduced in 2.2.4 typo that made servers "blocking" and
    hence unusable (they would get stuck in the accept(2) call);
    client-side sockets were also affected but that was not visible
    to an end-user because blocking robots may still work; the patch
    was posted to the Polygraph list
  - portability star, ncurses, #defines timeout causing namespace
    havoc
  - bad guys #defined `select' in Solaris system files causing
    namespace havoc
  - I/O buffer pool was not reporting memory growth correctly (err..
    at all)
  - prevent coredumps when printing a histogram with max value less
    than 1 (lx)
  - True64 requires a special setsysinfo(2) call to raise FD limit
    beyond the default hard limit of 4K


version 2.2.4
dated 1999-11-09

  - added "piper", a program to configure DummyNet network pipes
    based on PGL
  - added 'bwidth' -- a basic PGL type to represent [network]
    bandwidth small set of operations are supported for now
  - added NetPipe PGL type to describe network pipes; a pipe
    specifies maximum network bandwidth, packet delay and loss,
    and other low -level network parameters/conditions
  - added pipes.pg with definitions of commonly used network pipes,
    including modems and various kinds of origin servers
  - added configure-time check for DummyNet and IPFW interfaces
  - reduced start-up time in configurations with large number of
    robots and servers; reduced memory footprint for large
    configurations (more work may be needed)
  - print aggregate statistics (min/mean/max/etc) for histograms
    produced by lx and distr_test
  - report agent creation progress every 5 seconds rather than
    every 50 agents
  - report system resource usage before and after run
  - adjusted the way stat intervals (i- lines on the console) are
    printed in a blocking or overloaded environment
  - increase the maximum number of FD ./configure script can
    detect to 2^16 (65K)
  - fixed configuration bug in environments with no rlim_t type
  - include limits.h file to avoid compilation errors on Solaris
  - do not print "array probabilities (above) add up to .. less
    than 100%" if they add up to more than 99%
  - cntDownload in contents.pg was named cntDowload; some found it
    funny
  - lx could not handle logs with combination of duration-based
    and non-duration based phases
  - some environments do not know better than #define getc and
    putc macros causing namespace havoc
  - rptm_hist was printed twice by lx --objects All
  - a typo caused size type to do multiplication instead of
    division (PGL)


version 2.2.3
dated 1999-10-26

  - added "--sample_log" and "--sample_log_size" options to
    configure sample log; sample log defaults to the general
    purpose log; if separate log is specified, it is not flushed
    to disk on periodic basis as general log (to avoid potential
    run-time overhead)
  - added "StatsSample" object to PGL to describe the time and
    size of a statistical sample; Samples must be scheduled(),
    just like Phases; more work needed to make scheduling more
    convenient (phase related?)
  - added "kind" field to label Content object (PGL)
  - added "cntDowload" content to represent relatively large
    downloads; use cntDowload in PolyMix-2
  - disabled sharing of embedded objects among containers; with no
    sharing, we have to rely on user specified content
    configuration with no tools to "tune" the model internally --
    resulting (actual) global content distribution may not match
    the planned one; a likely global distribution is reported so a
    user can check their specs without running an experiment
  - disabled client side cache in PolyMix-2
  - set embedded recurrence to 100% in PolyMix-2
  - added initial support to save experiment "state"; eventually
    we will use state information to resume experiments from a
    given point and also for stats analysis; needs more work
  - added support for collecting low-level statistics in the form
    of samples; sample collection is controlled using PGL
    "StatsSample" type and "schedule()" call
  - for large configurations, inform about the progress in
    creating agents at startup
  - prevent int overflows when generating very large files
  - several bug fixes related to size constants (PGL)
  - try to handle "unlimited" resources reported by getrlimit(2)
    correctly


version 2.2.2
dated 1999-10-20

  - added "cache_cap" field to Robot (PGL); the cache is currently used
    for embedded objects only; it prevents robots from requesting the
    same embedded objects many times, emulating browser behavior
  - added "conn_lvl_mean" lx object to report average number of opened
    concurrent connections; because of Polygraph does not update time on
    every open() and close(), this statistics may not be accurate
  - robots now scan all servers (in a semi-random manner) before
    proceeding with truly random accesses; the initial scan ensures
    that all connectivity problems are detected early and also helps
    reach stable HR earlier
  - inform user when all robots are ready to generate hits on all
    servers
  - no "wait_xact_lmt" by default, a robot can queue as many
    transactions as needed; this is potentially dangerous because a user
    does not see those queued transactions (yet) and may think that
    everything is OK; more work is needed
  - generate new oids only when we know that the xaction will not be
    queued; this rule prevents robots from thinking an oid has already
    been seen by a proxy while it was not (because it got queued); the
    latter used to decreases offered hit ratio
  - agents should share random number generators to avoid a
    hard-to-detect artificial condition when all agents are "doing the
    same" all the time (e.g., all robots send requests to the same
    subset of servers for a while)
  - if no new alias is specified, just delete old ones (aka)
  - make sure that we always #include sys/types.h before inet.h because
    old BSD systems may not include sys/types.h in inet.h, and they
    should
  - removed --out option from aka
  - fixed a bug that led to an occasional assertion if the FD limit is
    reached on server side
  - fixed bugs leading to occasional segv and assertions when poll(2)
    system call is used
  - fixed parsing of the --dump option; now all tag combinations are
    parsed correctly
  - request rate field of a Robot was misinterpreted unless N/sec format
    was used (PGL)
  - due to ioctl(2) interface differences, aka does not work on Linux
    and probably some other OSes; more work is needed
  - fixed IP range parsing bug; some valid ranges were declared
    malformed
  - logging modifications; binary logs are not compatible with previous
    versions (again)
  - updated polymix-2.pg and contents.pg; changed content weights to
    ensure that an "average" object has 80% chance of being cachable


version 2.2.1
dated 1999-10-12

  - added support for IP ranges using a-b.c-d.e-f.g-h notation,
    for example '10.0.1-2.50-99' constant specifies an array of
    100 addresses; the old range operator (A .. B) is still
    supported but is less flexible; subnet and/or port
    specification is also allowed
  - added "aka", an ingeniously named tool to create [large]
    number of IP aliases for a given interface; aka accepts IP
    specs in the PGL format (a-b.c-d.e-f.g-h/subnet) which allows
    for specifying hundreds of aliases in a compact form; aka will
    _delete_ all aliases for the interface before setting new
    ones; aka requires superuser access, of course
  - added "new_oids_per_msg_max", "new_oids_prefetch", and
    "new_oids_history" options to control synchronization between robots
    and servers; may be useful if you get many oid-related errors in
    large scale experiments and/or when a proxy gets too slow or drops
    requests
  - added "open_conn_lmt" and "wait_xact_lmt" fields to Robot
    (PGL) to limit the number of concurrent connections a single
    Robot may have at a time, emulating browser behavior (the code
    was written for version 2.2.0, but lacked PGL hook-ups and was
    not tested)
  - removed place() function call and replaced 'host' field in
    Agent with 'hosts' field to reduce memory footprint when
    configuring lots of agents on a single machine; place() call
    used to clone lots of agent specs that would differ only in
    'host' field setting; we now specify all the hosts directly
    (in 'hosts' field) bypassing the cloning step (PGL)
  - added "conn_close_act_use_hist" and "conn_close_act_ttl_hist"
    lx objects to filter stats for "actively" closed connections
    only (i.e., all connections except those that were closed in
    an "idle" state)
  - agents where not binding to their addresses when they were
    supposed to
  - robots used to maintain one private object space as if there
    was only one origin server; the bug led to lower than expected
    hit ratios when robot's public_interest was less than 100%
  - robots were not setting server world id (wid) for embedded
    requests
  - statistics for idle persistent connections closed by Polygraph
    was not maintained
  - synchronized workload specs


version 2.2.0
dated 1999-09-28

  - added support for embedded objects: a server populates content with
    special tags that point to embedded objects (based on PGL Content
    specs); a robot parses server responses for those tags; a robot
    requests embedded objects as it detects them; we try to keep average
    request rate at the specified level (if any) despite these "extra"
    requests requests for embedded objects do cause bursts in traffic,
    just like in the real worlds
  - added may_contain and embedded_obj_cnt fields to Content type (PGL)
  - added "embed_recur" ratio to Robot; the ratio specifies the portion
    of embedded objects in a container that are re-requested, on average
  - added "choice_space" field to Content type (PGL); Choice space
    specifies the number of oids considered when selecting next embedded
    oid for a container oid:
      embedded_oid = uniform(k*container_oid, k*container_oid + choice_space)
  - added "direct_access" field to Server (PGL); direct_access selector
    specifies (a) objects that can be accessed not as an embedded part of
    other object and (b) relative frequency of such an accesses (e.g. 1%
    of all direct accesses are images and 95% of all direct accesses are
    HTML pages)
  - added tools/msl_test tool that attempts to estimate the maximum time
    a proxy keeps a TCP connection in a TIME_WAIT state. (Glenn Chisholm
    <glenn at ircache dot net>)
  - added rng_test to test the quality of various random number
    generators that Polygraph is using
  - added the "--dump" option to control what type of messages and what
    message parts must be dumped to console. The option accepts a list of
    flags; the old --prn_* interface was not flexible enough or required
    too many options; new interface needs more work
  - renamed "--prn_dump_size" to "--dump_size"
  - removed "--prn_reqs", "--prn_reps", and "--prn_errs" options
  - robots must bind(2) to the IP addresses they are running on except
    when all robots are running on the same address
  - report approximate time a server waited for an advertised oid to be
    requested
  - always randomize IO buffers before use
  - use agent id along with object id when seeding r.n.g; this prevents
    skew in pseudo-random numbers when many agents are dealing with the
    same small subset of oids
  - use one port manager for all addresses to reduce memory footprint for
    big scale runs
  - install SIG_INT (^C) handler _after_ polyclt/srv has configured
    itself; makes possible to kill a program if configuration takes
    forever
  - workload files were missing server side delays (Becky Larsen
    <balarsen at novell dot com>)
  - polymix-2.pg file comments were saying that it is a PolyMix-1 file
  - fixed typo in [client] "closed conn w/o sending data" error message
  - polymon.cc::TheSelHostCnt was not defined properly, causing
    compilation warnings (Ron Jones <ronjones at himalaya dot fc dot hp
    dot com>)
  - udp2tcpd.cc was using `int' instead of `socklen_t' causing
    compilation errors on Linux and others OSes that require socklen_t
    (Ron Jones <ronjones at himalaya dot fc dot hp dot com>)
  - a kludge to prevent mysterious (compiler?) bug causing segmentation
    faults in RecSym::getDistr on some platforms


version 2.1.0
dated 1999-09-17

  - added pop_test program that simulates an LRU-based cache and can be
    used to estimate [memory] hit ratios depending on popularity model
    and other related workload parameters
  - added "pop_model" field to Robot; two popularity models are
    supported:  pmUnif() and pmZipf(skew_factor).
  - added "public_interest", "recurrence", and "unique_urls" fields to
    Robot
  - added working_set_length() procedure call to PGL; use it to limit
    working set size and hence prevent hit ratio decline during long
    tests
  - added a "--prn_dump_size" option to limit the size of HTTP message
    dumps
  - added a "--prn_errs" option to print HTTP messages that caused
    xaction errors
  - recognize 'All' macro in --phase option (lx)
  - removed "--unique_urls" option (polyclt) -- it is now Robot's field
  - removed unused `world' options (polyclt): world_type, world_id,
    world_urls, unique_urls, order, recur, pop_model, tmp_loc,
    tmp_loc_delta, tmp_loc_depth, exp_oids, prefilled_cnt; some of these
    option were already implemented via PGL, and some wait till be
    implemented/ported/tuned
  - removed the "dhr" field from Robot specs (the field was ignored
    anyway)
  - share URL space among all robots and servers; robots may have a
    "private" URL subset while "public" subset is shared by all; servers
    send robots information about the current global state; current
    limitation is that all polyclt processes should emit request streams
    with similar rate (per robot differences are OK), otherwise the
    servers start complaining that some clients are not doing their
    share in creating the load; solving the latter problem would require
    more heavy negotiations among clients and servers
  - make IO buffer content "more random" than it used to be; servers now
    produce Web objects filled with more random content. Note that
    servers still may produce different content for the same URL, even
    if the headers imply that the object has not changed. The latter is
    probably OK under "normal testing conditions" though.
  - do NOT make relative URIs artificially long by prepending them with
    an '/http:/ip-address' prefix; transparent proxies usually receive
    relative URIs so they do have and advantage of handling shorter
    request-lines, and we probably should simulate that
  - HTTP/1.0 connections are non-persistent by default, no need to send
    *Connection: close header.
  - write all 'unique ids' (e.g., world id) using hex notation and fixed
    length fields
  - write oids in URLs using hex notation and fixed length fields
  - console now displays minutes since the start of an experiment rather
    than absolute time; absolute time is logged and is available to lx
  - when building executables, use CXXFLAGS instead of CFLAGS in
    Makefiles
  - "conn_ttl_vs_use" was erroneously named "conn_ttl_vs_sz"
  - fixed parsing bug that caused assertions on a "''" expression
  - offered (ideal) hit ratio was not recorded properly


version 2.0.0
dated 1999-09-07

  - new copyright file header and polished licensing terms
  - added support for PGL configuration language; most experiment
    parameters are now set via a configuration file
  - "--pop_model" option defaults to "unif"orm now (used to be "zipf")
  - added the "--idle_tout" option to the client side; "idle" in
    "--idle_tout" now means "no network I/O activity" -- Polygraph may
    still be trying to do something
  - added the "--stats_cycle" option to specify the duration of a cycle
    that collects and logs "cheap" stats (defaults to 5 seconds)
  - added "fill size" experiment goal
  - removed accept_lmt, rep_sz, obj_bday, obj_life_cycle,
    obj_life_cycle_var, obj_with_lmt, obj_expire, cool_phase, goal,
    launch_win, rep_cachable, maximize_req_rate, and perhaps other
    options; similar functionality is usually provided in PGL
  - renamed "--dhr" to "--recur" (recurrence ratio or how often a URL is
    revisited by a robot); in Polygraph 2.0.0 the actual DHR is
    recurrence/cachability ratio; DHR may be affected by popularity
    model and other factors; we had to rename "--dhr" because Polygraph
    can no longer simulate any given DHR independent from other config
    parameters -- the models are becoming too complex; this is still
    work in progress and changes are likely
  - removed `ephemeral' string as a valid port range in --ports
  - the "--file_scan" option now defaults to poll if poll(2) is
    supported; Polygraph used to call select(2) by default
  - added conn_close_frgn_use_hist,conn_close_frgn_ttl_hist,
    conn_close_lcl_use_hist,conn_close_lcl_ttl_hist, soread_sz_hist,
    sowrite_sz_hist, and phase_name objects to lx
  - made 'All' macro a default "object" to be extracted by lx
  - honor --phase option in trace mode of lx
  - changed binary log format; new format is not backwards compatible
  - log errno strings along with errnos; makes error logging portable
    across OSes
  - modified logging procedure to flush binary log data periodically
  - removed "X-ETag" header field
  - send Proxy-Connection: header when talking to a proxy (used to send
    Connection: which was a terrible idea and was not honored by some
    proxies)
  - added support for Content-Type header field in responses
  - added support for arbitrary number of user-defined simulation
    "phases"
  - cachability is now determined on the server side (again!)
  - added ./configure script to preconfigure the distribution before
    `make'
  - added INSTALL file with generic package installation instructions
  - added root-level Makefile
  - added distclean goal to Makefiles to remove most auto-generated
    files
  - changed Perl interpreter name in scripts to '/usr/bin/perl'; ideally
    we need to determine the location at ./configure time
  - explicitly require Perl version 5.003 or higher in Perl scripts
  - added DataComm-1 specs to bb.pl
  - added workloads directory with standard workloads specs written in
    PGL.
  - added polymix-1.pg, polymix-2.pg, and datacomm-1.pg workload specs
  - added simple.pg, a minimalistic workload to use as a "Hello World"
    example
  - complain about "uncachable hits"
  - ignore "false hits" by default
  - removed hard coded limits on the reply content size; the change may
    have performance effect for workloads with zipf popularity model
  - removed 'loop' tool until it gets fixed
  - applied some HPUX compatibility patches (submitted by James Murphy
    <murphy@fc.hp.com>)
  - 'max' values printed by distr_test was greater than real max by one
  - lots of other additions, modifications, and bug fixes
  

version 1.3.2
dated 1999-08-30

  - this minor release incorporates all previously released patches for
    1.3.1; the pathces fix a few logging bugs and, to the best of our
    knowledge, do not affect Polygraph run-time performance
  - replaced the "--prn_trace" lx switch with the "--trace" option; now
    trace stats can be averaged at a specified time interval; small
    window sizes emulate old behavior
  - added "conn_use_mean" object to lx
  - added datacomm-1 workload specs to bb.pl script
  - increment error count on each phase/log
  - fixed generation of class-based object names
  - fixed lx coredump when extracting class-based stats like 
    class_rptm_mean:hit


version 1.3.1
dated 1999-06-16

  - added the "--notify" option that enables notification messages to be
    sent to a monitoring program; messages (currently less than 100
    bytes) are sent via UDP every 20 seconds.
  - added "--label" option to specify a [short] run description; the
    label gets included into notification messages if any.
  - added udp2tcpd, a daemon that runs on port 18256 (default), listens
    to notification messages (UDP), and forwards them to polymon(s) via
    TCP; the intention is to support multiple monitoring programs for
    the same notification stream without using IP multicast or broadcast
  - added polymon; a ncurses-based program that monitors run-time status
    of Polygraph experiments using udp2tcpd daemon
  - added the err_cnt_tbl option to lx to print error table; note that
    Unix error codes are not standardized so you may get different
    descriptions of error messages if you move binary logs around (this
    is a bug)
  - fixed "invalid port" assertion in ExpPortMgr
  - fixed logging of error table (it probably was not logged before)
  - fixed compile-time warnings reported on Linux
  - fixed compile-time poll(2) errors on Linux
  - fixed a few compile-time problems on Solaris
  - maybe improved timegm() port to True64 and other environments with
    tm_gmtoff
  - removed custom polyVersion dependency from Makefile; it caused too
    many re-compilations and we never used the $CompileTime$ feature
    anyway
  - polished comments in Makefiles


version 1.3.0
dated 1999-06-08

  - added poll(2) support; users must add -DLACK_POLL to DEFINES
    in src/xstd/Makefile in the environments without poll(2);
  - added the "--file_scan" option to select between poll(2) and
    select(2); the default is still select, but that is likely to change
  - added the "--maximize_req_rate" option that enables "maximum request
    rate" searching mode; must be used together with the "--req_rate"
    option which specified initial rate; search is done by incrementing
    or decrementing actual request rate depending on the reply rate;
    support is rudimental, more work needed
  - added the "--prn_rep_cnt" option to lx; similar to --prn_time;
    prepends trace lines with number of replies received since log start
  - added response time statistics for major request classes:
    hits, misses, cachable, uncachable, etc.
  - added several lx objects to extract new stats: conn_use_hist,
    conn_ttl_vs_use, resp_tm_vs_class, class_rptm_mean
  - added stats for persistent connections (xactions per connection)
  - "rep_rate" and "req_rate" objects are now traceable via lx
  - log errors "histogram"
  - scan the port range and mark used ports at start-up if port manager
    is enabled via the "--ports" option; the scan adds about 2.5 seconds
    to polyclt start but avoids some of the run-time port binding errors
  - improved random number generation; do not use object ids as r.n.g
    seeds directly; generate a "good" "uncorrelated" random value and
    use that instead; prevents "loops" in reply size generation and
    other oid-dependent models; the loops were visible only on some
    micro-level workloads though; 
    the fix adds a few seconds to polyclt/srv start time and about 4MB
    to memory footprint
  - adjusted histogram dumps so that max column in the output
    corresponds to max rather than max+1
  - avoid floating point exceptions when reading bogus log data
  - improved handling of incomplete or old binary logs in lx
  - fixed FP exception error due to wrong double->int cast
    (a patch was available for 1.2.2)
  - use "linux" #define to prevent "FD_SETSIZE already defined"
    warnings on Linux (one can also add -DLINUX in Makefiles)


version 1.2.2
dated 1999-05-21

  - added distr_test tool that can print a histogram for any
    distribution recognized by Polygraph
  - added the "--prn_trace" lx option to print trace stats
    rather than totals; not all object values can be computed in
    the middle of a log; those that can, will be printed; others
    will be silently ignored; log files are not joined when trace
    mode is on
  - added the "--prn_time" lx option to show log time as a first
    column of the output (useful together with --prn_trace)
  - added support for accumulating large sizes (over 2GB);
    yet untested; old counters used to overflow leading to 
    bogus byte hit ratios; current counters can hold up to
    about 4 exabytes which should be enough for a while
  - timegm is missing on Solaris; Solaris users should add 
    -DLACK_TIMEGM to DEFINES in xstd/Makefile to enable a
    workaround
  - several bug fixes in Histogram module; trace stats
    (collected at 90 second intervals) that were based on
    histograms (e.g., response time percentiles) where not
    recorded correctly; aggregate stats (e.g., means) and stats
    averaged over entire phase were not affected
  - Zipf distribution was not generating the value of '1' when
    used for persistent connection limits; other zipf fixes
  - fixed "ambiguous overload for `bool ? Size : int'" compilation
    errors
  - zipf distribution now reports "world size" parameter only to
    be consistent with the way zipf is specified on the command
    line (used to print alpha=1 as a first parameter)
  - other minor bug fixes


version 1.2.1
dated 1999-05-13

  - added the "--obj_bday" option to specify object creation
    times; used to be hard-coded to a randomly (per object) chosen
    day in the 70s; negative birthdays are relative to program
    start time; non-negative birthdays are relative to 0, UTC;
  - accept "zipf" distribution on command line
  - time parsing routines now accept "year" scale
    (e.g., const:1.5year)
  - report Polygraph version in the configuration dump
  - internal lmt and expires time must be rounded using second
    resolution for HTTP date comparisons to work correctly
  - polished last-modified-time calculations to better handle lmts
    that are close to current time
  - renamed XSTD_INCLUDE to LIB_INCLUDE in xstd/Makefile


version 1.2.0
dated 1999-05-01

  - added Object Life Cycle model to simulate object modification and
    expiration; the model is controlled by the following server side
    options: --obj_life_cycle, --obj_life_cycle_var, --obj_with_lmt,
    and --obj_expire
  - support If-Modified-Since requests on server side
  - Poly-server now adds the Date: header field to all replies
  - removed "max-age" option from cachable replies because it had
    priority over the more common Expires: header. As a side effect
    not all cachable replies have expiration information
  - Last-Modified header field is now added to replies only if
    --obj_life_cycle option is enabled; some proxies will not cache
    replies without a Last-Modified header field -- watch out!
  - Expires header fields are not added to cachable replies by default;
    see --obj_expire option to control Expires fields
  - reordered HTTP reply header fields to follow HTTP recommendations
  - always use the minimum of FD_SETSIZE and getrlimit(RLIMIT_NOFILE);
    warn if FD_SETSIZE is smaller; we got tired of coredumps when
    a tester would forget to increase FD_SETSIZE after increasing
    kernel limits
  - date manipulation functions now use "timegm()" call which may
    not be portable; portability problems will be fixed on-demand
  - distinguish between "premature end of msg body" and "premature end
    of msg headers"; useful to diagnose proxy connection resets
  - detect premature end of headers on client side (we probably would
    wait forever prior to this fix)
  - reorganized and optimized HTTP header parsing; parsing speed is
    increasingly important as we have to recognize more header fields;
    current improvement (on 2.5 fields) is negligible (about 3%).
  - fixed a bug with HTTP header parsing (a patch was available for
    1.1.0)


version 1.1.0
dated 1999-04-25

  - added a "--version" option to print package version and (c) info
  - ident-like routines may extract version info from Poly binaries now
  - added a "--pconn_use_lmt" option to control the number of
    transactions executed over a single [persistent] connection; Poly
    generates (and understands) Connection: close/keep-alive headers,
    and will honor Proxy-Connection: header as well; mutli-token
    Connection: headers are not supported; the option makes sense on
    both client and server sides; TCP may need "--nagle off" to utilize
    the advantage of pconns
  - added support for user-defined (tabulated) distributions;
    "tab:filename" or "tab(filename)" can be used wherever a
     distribution is expected on the command line
  - changed the default of the "--origin" option to "127.0.0.1:8080"
  - the "--proxy" option has no default now and implies proxied
    connection if present; with no "--proxy" option, a direct connection
    is assumed
  - removed the "--abs_urls" option; absolute (relative) urls are now
    generated only for proxied (direct) traffic
  - added libs target to Makefile to ease re-build of libraries
  - make will now clean src/xstd directory when making clean in src
  - the "--rng_seed" option is now honored by all rnd number generators
  - complain if units (KB, sec, etc.) are specified where none expected
  - added reporting of source code location in error messages
  - check for connect errors during first IO on a socket; Poly 1.0 would
    do an I/O and only then check for an error leading to imprecise
    error diagnostics
  - set socket options for accept(2)-ed sockets (server side), do not
    rely on inheritance; BSD OSes silently suppress inheritance of some
    flags like TCP_NODELAY (Nagle algorithm)
  - response time now includes connection setup time
  - fixed member initialization bug in StatPhase.cc that caused 
    coredumps on Linux

  
version 1.0.7
dated 1999-04-05

  - added rep_sz_hist, rep_sz_mean, resp_tm_vs_sz, req_bhr, rep_bhr
    objects to 'lx' (byte HRs are broken for long experiments)
  - added --track_rports and --rport_wait_min options to track TCP port
    usage on the proxy side; unfortunately tracking is complicated by
    known TCP violations of most BSD implementations
  - fixed 'lx' bug with aggregating reply rate from logs with
    different phase durations
  - applied bake-off mods to bb.pl


version 1.0.6
dated 1999-03-10

  - added "lx", a routine to eXtract objects from binary logs; also
    mergers logs to support multiple client/server experiments
  - added "exprep.pl" script to generate reports from binary logs
    of several experiments (needs more work)
  - replaced all ETag: headers with X-ETag (requests and replies); 
    ETag is not a request header and gets filtered out on some proxies
  - added "Last-Modified: Wed, 18 Feb 1998 17:53:58 GMT" reply header 
    to cachable replies; some proxies may not cache replies otherwise
    (a magic constant value should be eventually eliminated)
  - changed the default for the "--log_size" option to 10KB
    with no logging and 10MB with logging enabled
  - various fixes to handle log buffer overflows; we now ignore all
    new entries if the buffer is full (needs more work)
  - fixed a lot of bugs in interpreting logged data (recording was OK?)
    no program was interpreting logs so bugs stayed undetected
  - mandatory phases should not stop even when too many errors;
    we used to abort if that happens (needs more work to detect
    error flood early as we used to)
  - increased required verbosity level for "got N xactions..." message
    to 2; a more detailed but less readable progress/goal message is
    printed with a verbose level of 0.


version 1.0.5
dated 1999-02-23

  - added "--prefilled_cnt" option
  - added Uniform Popularity Model
  - minor polish and bug fixes


version 1.0.4
dated 1999-02-22

  - added "--ign_false_hits" option; by default false hits are
    now treated as xaction errors
  - added "--prn_false_misses" option; handy to see what hits
    a proxy has "missed"
  - added the "--tmp_loc_depth" option that specifies a soft limit
    on inter-request distances in tmp locality model
  - added "--tmp_loc_delta" option to specify fuzziness of temporal 
    locality choices
  - added "--cool_phase" option to specify minimal cool-off phase;
    handy when you run more than one polyclt and do not want one
    of them to stop when others are still in their measurement phase
  - added "--fd_limit" option to lower FD limit supplied by OS 
    (as a safeguard for OSes that crash when we run out of FDs)
  - added "--phase" option to log reader to show more stats about
    a particular phase (needs more work)
  - added support for error limit (given in the --goal option)
  - added ETag headers to pass object specific info from the client 
    to the server
  - better facilities for logging and reporting various errors
  - record ideal (i.e, offered) Hit Ratio
  - record actual cachability ratio
  - added lognormal distribution to the list of distributions
    available on the command line (logn:mean,sdev)
  - print number of hits, misses, errors, etc. in lr
  - enforce a safeguard FD limit of (0.97*rcur - 10), where "rcur"
    is the FD limit enforced by OS according to getrlimit(2)
    the "--fd_limit" option can be used to lower this value
  - shutdown nicely on exit or fatal external error
  - count and report the number of open sockets; the last column
    of the console output now shows number of open FDs, not just
    pending xactions
  - revised traffic model operation and simplified the interface
    now traffic characteristics are controlled individually rather
    than via an ugly --world_oids option
  - constant hit ratio now works correctly regardless of cachability
    ratio and other traffic parameters
  - moved --rep_cachable option from the server side to the client 
    side
  - changed tmp locality model to use future "plan" instead of past
    "history"; old model was emitting too many too close requests;
    current model follows the --tmp_loc distribution much better
  - complain if cachability status of a reply has changed
  - print various FD limits on start
  - r.n.g. seed was not properly changed when calculating reply sizes,
    resulting in same object ids having different content length if
    requested more than once by a proxy
  

version 1.0.3
dated 1999-02-15

  - added initial support for Constant Hit Ratio; we have several
    models (Object Ids distributions) to choose from, see
    --world_oids
  - added --world_oids option to specify Object Ids
    "distribution"; currently supported "distributions" meaningful
    for --world_oids are:
      . sequential ("seq"),
      . MemoryLess Zipf ("MLZipf"),
      . Hot/Cold ("HoCo");
    names will change if we find better ones
  - changed default behavior when no --world_oids is specified: we
    used to generate Zipf-like stream of Object Ids by default,
    now the default is Sequential stream (hence, no hits by default)
  - removed --world_cap option; we no longer need/use World Capacity
  - added "Expires: Wed, 17 Feb 2000 03:35:25 GMT" header to
    cachable responses; this constant should be good enough in
    most cases and will be changed to a dynamic value in next
    releases
  - added "Pragma: no-cache" to uncachable responses
  - better explanation for errors with distribution specs on the
    command line
  - fixed zero Content-Length bug
  - fixed time accounting bug (visible at least on FreeBSD 3.0)
  - define _BSD_SIGNALS to make IRIX happy (needs more work)


version 1.0.2
dated 1999-02-12

  - added support for specifying distributions on the command line;
    currently available distributions: unif, exp, norm, and const
  - added support for specifying ratios and such on the command line;
  - "--rep-size" is now of type Size Distribution (default: exp(13KB))
  - "--xact_think" is now of type Time Distribution
  - "--rep_cachable" is now of type Ratio (e.g. 80%)
  - renamed "--users" to "--robots"
  - value "0" does not require scale any more ("0" == "0sec" == "0min")
  - report number of outstanding xactions in i-stats (new last column)
  - increased verbosity level required for i-stats to 2
  - fixed parsing of floating point values on the command line
    (used to be truncated to int)
  - #warn, not #err if FD_SETSIZE is #defined suspiciously early
  

version 1.0.1
dated 1999-02-07

  - added time support in goal option
  - enabled --launch_win support
  - enabled --xact_think support 
    (per xaction think times on both sides)
  - added constant req submission rate mode (--req_rate)
  - replaced --req_ccl with --users (just a name change)
  - added support for absolute/relative urls (--abs_urls option)
  - added Host: header (all requests)
  - many binary logs fixes and improvements
  - many stats fixes
  - disable SO_LINGER if linger_tout == 0
  - drastically improved memory management; 
    now Poly runs out of filedescriptors before running 
    out of memory on high loads
  - account for BSD select(2)'s magic limit on timeout value
  - internal alarms now use Heap instead of LinkedList

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