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Old 04-17-2010, 05:35 PM   #1
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Problems with valgrind on httpd

Hello all,

In general I want to run callgrind on one of apache module and from the valgrind documentation I found that it is not possible because valgrind requires to run with executable (please correct me if I understood something wrong from documentation).
So now I'm trying to run callgrind with httpd but still have following problem:
Apache doesn't accept any URL. If I run httpd without valgrind everything works fine for me, but with valgrind nothing work.
Also, after some time valgrind crashes.

Can you please let me know what I'm doing wrong?
I think that it relates to some configurations of httpd or some valgrind options but I can't get the correct configuration.
This is very urgent for me so if you can please help me ASAP.

Thanks in advance,
Old 04-17-2010, 06:05 PM   #2
Registered: Feb 2002
Location: Grenoble
Distribution: Debian
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It may be that the slowdown caused by valgrind is enough to cause timeouts. Do you just want to run callgrind for profiling or you have more needs? It may be that you can use some specific options, but it depends on the things you want to do.
Old 04-18-2010, 03:20 AM   #3
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Hi Mara,

Thank you for response!

I just want to run callgrind for profiling to catch the slow parts of specific module of httpd.
Can you please send me those specific options which may fix my problem?
In addition after some time work valgrind prints out a lot of following messages:

Thread 299: status = VgTs_WaitSys
==25465== at 0x597FCF9: pthread_cond_wait@@GLIBC_2.3.2 (in .../
==25465== by 0x530A71A: apr_thread_cond_wait (in .../
==25465== by 0x45A946: ap_queue_pop (in .../httpd)
==25465== by 0x45797D: worker_thread (in .../httpd)
==25465== by 0x5317F1C: dummy_worker (in .../
==25465== by 0x597BF96: start_thread (pthread_create.c:297)
==25465== by 0x5E642DC: clone (in .../

and exits with following message:

Note: see also the FAQ.txt in the source distribution.
It contains workarounds to several common problems.

If that doesn't help, please report this bug to:

In the bug report, send all the above text, the valgrind
version, and what Linux distro you are using. Thanks.

Looking forward to hear back from you soon.

Thanks in advance,
Old 04-21-2010, 03:53 AM   #4
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Problems with valgrind on httpd Reply to Thread (resolved)


I found the problem and I think that solution might be useful for someone, so I'm posting it.
The problem was related to a number threads that httpd invoked. In valgrind (in latest version as well: 3.5.0) defined
#define VG_N_THREADS 300 (file include/pub_tool_threadstate.h)
which sets the limitation of invoked threads and if application runs more than 300 threads valgrind crashes.
If you changed this number and rebuild the valgrind your problem will be resolved.

Best Regards,


httpd, valgrind

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