Re: Netperf throughput vale only has 1.6Mb/sec

From: Alex Rousskov (rousskov@measurement-factory.com)
Date: Mon Feb 05 2001 - 17:53:16 MST


On Mon, 5 Feb 2001, Rick Jones wrote:

> > Netperf ties response time and throughput and, hence, cannot show
> > meaningful throughput measurements in environments with packet delays.
>
> Huh? Are you refering to the synchronous nature of the netperf TCP_RR
> test? If so, then it was _inteneded_ to show the delay and was not
> intended as a throughput measurement.

I was actually talking about the [default] TCP_STREAM test.

I had no intention to somehow pummel the test or the netperf tool
itself! I was just pointing out that the default TCP_STREAM test will
not show real raw throughput on a link with packet delays.

For example, TCP_STREAM reports ~1.6Mbit/sec throughput with PolyMix-3
server-side delays (40msec in each direction) and a 100Mbit link. The
actual throughput (e.g., a throughput that an HTTP client may see) is
above 80Mbits/sec.

If there are more appropriate netperf tests/parameters that should be
used in an environment with delays, please let me know! The defaults
were sufficient for our limited tests, but we are always happy to
improve the methodology.

Thank you,

Alex.



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