[httperf] fd-unavail non-null

Arlitt, Martin martin.arlitt at hp.com
Tue Aug 31 14:33:09 PDT 2010

Hi Sylvain

Using more client machines with less load on each of them is a good approach.

Some other suggestions are available in the mailing list archive. In particular, you may want to read through the thread "httperf: connection failed with unexpected error 99" that appeared in February and March 2009. Included in that thread is a detailed explanation of what is happening (from Rick Jones).

The archive is available at

and the specific months are




-----Original Message-----
From: Sylvain GENEVES [mailto:Sylvain.Geneves at inrialpes.fr] 
Sent: Tuesday, August 31, 2010 2:18 PM
To: Arlitt, Martin
Cc: 'Sylvain GENEVES'; httperf at linux.hpl.hp.com
Subject: RE: [httperf] fd-unavail non-null

Hi Martin

you got it!! there are indeed connections in TIME_WAIT state.
could you tell me what is the right thing to do to avoid that? my guess
would be to use more client machines with less load on each one ?


> Hi Sylvain
> Have you checked if it is an issue with too many TCP connections on the
> client ending up in the TIME_WAIT state? If you haven't, run
> $ netstat -an | grep TIME_WAIT | wc -l
> Thanks
> Martin
> -----Original Message-----
> From: httperf-bounces at linux.hpl.hp.com
> [mailto:httperf-bounces at linux.hpl.hp.com] On Behalf Of Sylvain GENEVES
> Sent: Tuesday, August 31, 2010 1:39 PM
> To: httperf at linux.hpl.hp.com
> Subject: [httperf] fd-unavail non-null
> Hi,
> I run httperf on linux using --wsesslog=45371,0.000,/my_sessions_path
> --rate=2000 and --timeout=3 for a big overload test.
> what i don't understand is that it tells me fd-unavail is non-null (tens
> of thousands actually), though i've dramatically increased the max open
> files limit to 786762. I've tried to increase it to 5000000, but the
> results are the same : there're still the fd-unavail errors...
> I've had a doubt, but it appears that the per-process max open files limit
> on linux is shown by "ulimit -n", so i first modified system-wide settings
> (through sysctl), then in PAM (/etc/security/limits.conf), then in ulimit.
> I've modified the code to count EINVAL errors in a separate way, thus
> fd-unavail only counts EMFILE errors, no change...
> does someone know what's going on?
> also, i don't know if it's related, but i see a strange behaviour when i
> launch multiple instances of httperf :
>  - they don't finish at the same time (some instances finish tens of
> minutes later than the first one)
>  - in the end the remaining instances should be doing 2000sessions/sec,
> but instead they do ~2requests/sec : the server is so idle i can check it
> live with tcpdump...
> Regards,
> Sylvain
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