Change log

version 3.3.0
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
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
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
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
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
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
2007/03/07
- Fixed the 'theInOff <= theCapacity' assertion.


version 3.1.0
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
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
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
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


2.7.4 -> 2.7.5
20011231
- 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

2.7.3 -> 2.7.4
20010922
- 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


2.7.2 -> 2.7.3
20010830
- 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


2.7.1 -> 2.7.2
20010813
- 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

2.7.0 -> 2.7.1
20010803
- 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

2.6.5 -> 2.7.0
20010729
- 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


2.6.4 -> 2.6.5
20010729
- 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

2.6.3 -> 2.6.4
20010709
- 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


2.6.2 -> 2.6.3
20010627
- 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

2.6.1 -> 2.6.2
20010613
- 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

2.6.0 -> 2.6.1
20010605
- 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

2.5.5 -> 2.6.0
20010522
- 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


2.5.4 -> 2.5.5
20010501
- 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


2.5.3 -> 2.5.4
20000724
- 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


2.5.2 -> 2.5.3
20000719
- 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


2.5.1 -> 2.5.2
20000713
- 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


2.5.0 -> 2.5.1
20000626
- 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)


2.2.8 -> 2.2.9
20000113
- 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


2.2.7 -> 2.2.8
19991227
- 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


2.2.6 -> 2.2.7
19991215
- 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

2.2.5 -> 2.2.6
19991207
- 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


2.2.4 -> 2.2.5
19991129
- 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


2.2.3 -> 2.2.4
19991109
- 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)


2.2.2 -> 2.2.3
19991026
- 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


2.2.1 -> 2.2.2
19991020
- 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

2.2.0 -> 2.2.1
19991012
- 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


2.1.0 -> 2.2.0
19990928
- 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

2.0.0 -> 2.1.0
19990917
- 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


1.3.2 -> 2.0.0
19990907
- 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


1.3.1 -> 1.3.2
19990830
- 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

1.3.0 -> 1.3.1
19990616
- 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


1.2.2 -> 1.3.0
19990608
- 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)

1.2.1 -> 1.2.2
19990521
- 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


1.2.0 -> 1.2.1
19990513
- 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


1.1.0 -> 1.2.0
19990501
- 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)


1.0p7 -> 1.1p0
19990425
- 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


1.0p6 -> 1.0p7
19990405
- 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


1.0p5 -> 1.0p6
19990310
- 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.


1.0p3 -> 1.0p5
19990223
- added "--prefilled_cnt" option
- added Uniform Popularity Model
- minor polish and bug fixes


1.0p3 -> 1.0p4
19990222
- 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


1.0p2 -> 1.0p3
19990215
- 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)


1.0p1 -> 1.0p2
19990212
- 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


1.0p0 -> 1.0p1
19990207
- 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