[httperf] Strange behavior of the httperf

Arlitt, Martin martin.arlitt at hp.com
Sun May 20 07:44:04 PDT 2012

Hi Aleksandr

Httperf using 100% of a single CPU core is normal behavior.

My guess as to the problem you are experiencing is that you are quickly exhausting the available file descriptors, i.e., they are all ending up in the TIME_WAIT state.  After starting your httperf run, try “netstat –an | grep TIME_WAIT | wc –l”. if there is a large number, then that is the problem, and you will need to enable time wait recycling (there are messages in the mailing list archive about this).


From: httperf-bounces at linux.hpl.hp.com [mailto:httperf-bounces at linux.hpl.hp.com] On Behalf Of Aleksandr Vinokurov
Sent: Sunday, May 20, 2012 6:07 AM
To: httperf at linux.hpl.hp.com
Subject: [httperf] Strange behavior of the httperf

Hello all,

I'm measuring the req/s for the Webmachine -- an Erlang web server, basically I just want to start with measures of vanilla Webmachine, and move further after I settle the testing method.

I start a basic hello-world Webmachine app on a 8 core server and run httperf (build with FD_SETSIZE 65535 --  http://gom-jabbar.org/articles/2009/02/04/httperf-and-file-descriptors ) with options like this:

httperf --verbose --hog --timeout=1 --client=0/1 --server=srv2-4pd-spgl04 --port=9080 --uri=/hello/world --rate=10000 --send-buffer=4096 --recv-buffer=16384 --num-conns=10000 --num-calls=1

The result for this task shows about 5700 req/sec and 1.74 s for test.

Then I try to run a times 10 connections with this options:

httperf --verbose --hog --timeout=1 --client=0/1 --server=srv2-4pd-spgl04 --port=9080 --uri=/hello/world --rate=10000 --send-buffer=4096 --recv-buffer=16384 --num-conns=100000 --num-calls=1

And then I see a short growth of erl CPU usage and then saturation to the 1-2% while httperf flies to 100% (of one core) and keep running for long, until killed by me.

Does anybody saw such operation of the httperf and can describe me the case of the problem?

Александр Винокуров
+7 (921) 982-21-43

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