[OpenSIPS-Users] sched_yield()

Alex Massover alex at jajah.com
Thu Jan 21 13:23:51 CET 2010 

Hi,

Another one.. It hangs for a number of seconds (but it's enough to cause to SIP timeouts - MSG queue jumps to 260K), it's hard to make a bt at the right moment.
This one looks better because there's sched_yield() there :)

(gdb) bt
#0  0xb77d5424 in __kernel_vsyscall ()
#1  0xb771041c in sched_yield () from /lib/i686/cmov/libc.so.6
#2  0x080bf23d in new_avp ()
#3  0x080bf53f in add_avp ()
#4  0xb72c1c9c in ?? () from /usr/lib/opensips/modules/dialog.so
#5  0x08055030 in do_action ()
#6  0x08053ebf in run_action_list ()
#7  0x08056e7a in do_action ()
#8  0x08053ebf in run_action_list ()
#9  0x08056e7a in do_action ()
#10 0x08053ebf in run_action_list ()
#11 0x08056e7a in do_action ()
#12 0x08053ebf in run_action_list ()
#13 0x08057d99 in run_top_route ()
#14 0x0808ad6c in receive_msg ()
#15 0x080bd2f2 in udp_rcv_loop ()
#16 0x08069339 in main ()

--
Best Regards,
Alex Massover
VoIP R&D TL
Jajah Inc.

> -----Original Message-----
> From: users-bounces at lists.opensips.org [mailto:users-
> bounces at lists.opensips.org] On Behalf Of Alex Massover
> Sent: Thursday, January 21, 2010 2:05 PM
> To: OpenSIPS users mailling list
> Subject: Re: [OpenSIPS-Users] sched_yield()
> 
> Hi Andrei,
> Hopefully this is it (with FASTLOCK)
> 
> #0  0xb77d5424 in __kernel_vsyscall ()
> #1  0xb772babb in poll () from /lib/i686/cmov/libc.so.6
> #2  0xb77ba83a in ?? () from /lib/i686/cmov/libresolv.so.2
> #3  0xb77b8946 in __libc_res_nquery () from
> /lib/i686/cmov/libresolv.so.2
> #4  0xb77b8fdb in ?? () from /lib/i686/cmov/libresolv.so.2
> #5  0xb77b92ae in __libc_res_nsearch () from
> /lib/i686/cmov/libresolv.so.2
> #6  0xb77b96d4 in __res_nsearch () from /lib/i686/cmov/libresolv.so.2
> #7  0xb77b808a in res_search () from /lib/i686/cmov/libresolv.so.2
> #8  0x0808c613 in get_record ()
> #9  0x0808cf05 in ?? ()
> #10 0x0808e385 in sip_resolvehost ()
> #11 0x0807a26c in mk_proxy ()
> #12 0xb7627d39 in t_relay_to () from /usr/lib/opensips/modules/tm.so
> #13 0xb7634501 in ?? () from /usr/lib/opensips/modules/tm.so
> #14 0x08055030 in do_action ()
> #15 0x08053ebf in run_action_list ()
> #16 0x08095cf2 in eval_expr ()
> #17 0x080958d9 in eval_expr ()
> #18 0x08095919 in eval_expr ()
> #19 0x080554e2 in do_action ()
> #20 0x08053ebf in run_action_list ()
> #21 0x08056e7a in do_action ()
> #22 0x08053ebf in run_action_list ()
> ---Type <return> to continue, or q <return> to quit---
> #23 0x080569d8 in do_action ()
> #24 0x08053ebf in run_action_list ()
> #25 0x08056e7a in do_action ()
> #26 0x08053ebf in run_action_list ()
> #27 0x08057d99 in run_top_route ()
> #28 0x0808ad6c in receive_msg ()
> #29 0x080bd2f2 in udp_rcv_loop ()
> #30 0x08069339 in main ()
> (gdb)
> 
> --
> Best Regards,
> Alex Massover
> VoIP R&D TL
> Jajah Inc.
> > -----Original Message-----
> > From: users-bounces at lists.opensips.org [mailto:users-
> > bounces at lists.opensips.org] On Behalf Of Andrei Dragus
> > Sent: Wednesday, January 20, 2010 2:58 PM
> > To: OpenSIPS users mailling list
> > Subject: Re: [OpenSIPS-Users] sched_yield()
> >
> > Hi,
> >
> > I think that there is a lock that is being held more than it should
> be
> > and that's what causes starvation. It would help us if you could
> attach
> > to a process using gdb and give us a full backtrace.
> >
> > Temporary solutions which should work would be to reduce the number
> of
> > processes to 4-6 or to recompile replacing -DFAST_LOCK with one of
> the
> > other options (-DUSE_POSIX_SEM or -DUSE_PTHREAD_MUTEX) but we should
> > see
> > where this is from to fix it.
> >
> > Alex Massover wrote:
> > > Hi!
> > >
> > > Yes, from the source on debian, I build deb package. (I did some
> > minor changes to the source, but the problem happens also without my
> > changes)
> > > 16 children on 4 cores.
> > >
> > > What do you suggest to reduce it to 4? It runs on 2.6.32 on VMware
> > ESX.
> > >
> > > I'm also trying now sleep(0) instead of sched_yield().
> > >
> > > --
> > > Best Regards,
> > > Alex Massover
> > > VoIP R&D TL
> > > Jajah Inc.
> > >
> > >> -----Original Message-----
> > >> From: users-bounces at lists.opensips.org [mailto:users-
> > >> bounces at lists.opensips.org] On Behalf Of Andrei Dragus
> > >> Sent: Wednesday, January 20, 2010 1:05 PM
> > >> To: OpenSIPS users mailling list
> > >> Subject: Re: [OpenSIPS-Users] sched_yield()
> > >>
> > >> Hi Alex,
> > >>
> > >> Are you building OpenSIPS from source?
> > >> How many processes do you have and on how many cores?
> > >>
> > >>
> > >> Alex Massover wrote:
> > >>
> > >>> Hello!
> > >>>
> > >>> I'm facing a strange problem, sometimes under a stress OpenSIPS
> > >>> "locks" - load average jumps, SIP processing delays, opensips msg
> > >>> queue fills with a lot of sip messages, opensips processes start
> to
> > >>> comsume a lot of CPU.
> > >>>
> > >>> And strace shows:
> > >>>
> > >>> sched_yield()
> > >>>
> > >>> sched_yield()
> > >>>
> > >>> sched_yield()
> > >>>
> > >>> sched_yield()
> > >>>
> > >>> ....
> > >>>
> > >>> for all processes.
> > >>>
> > >>> If I stop the stress - after a while (not immediately) - it
> > unlocks,
> > >>> also suddenly, I can see in top that all opensips processes stop
> to
> > >>> consume CPU.
> > >>>
> > >>> What can it be? Some kind of starvation?
> > >>>
> > >>> --
> > >>>
> > >>> Best Regards,
> > >>>
> > >>> Alex Massover
> > >>>
> > >>> VoIP R&D TL
> > >>>
> > >>> Jajah Inc.
> > >>>
> > >>>
> > >>>
> > >>> This mail was sent via Mail-SeCure System.
> > >>> -----------------------------------------------------------------
> --
> > --
> > >>>
> > >> ---
> > >>
> > >>> _______________________________________________
> > >>> Users mailing list
> > >>> Users at lists.opensips.org
> > >>> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> > >>>
> > >>>
> > >> --
> > >> Andrei Dragus
> > >> www.voice-system.ro
> > >>
> > >>
> > >> _______________________________________________
> > >> Users mailing list
> > >> Users at lists.opensips.org
> > >> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> > >>
> > >> This mail was received via Mail-SeCure System.
> > >>
> > >>
> > >
> > >
> > > This mail was sent via Mail-SeCure System.
> > >
> > >
> > >
> > > _______________________________________________
> > > Users mailing list
> > > Users at lists.opensips.org
> > > http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> > >
> >
> > --
> > Andrei Dragus
> > www.voice-system.ro
> >
> >
> > _______________________________________________
> > Users mailing list
> > Users at lists.opensips.org
> > http://lists.opensips.org/cgi-bin/mailman/listinfo/users
> >
> > This mail was received via Mail-SeCure System.
> >
> 
> 
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