Re: [patch] voluntary-preempt-2.6.8-rc3-O4

Lee Revell
2004-08-10T08:18:11Z

On Tue, 2004-08-10 at 04:09, Ingo Molnar wrote:
> * Lee Revell <rlrevell@joe-job.com> wrote:
>
> > Here is another one I got starting jackd. Never seen it before today.
> >
> > (jackd/778): 14583us non-preemptible critical section violated 1100 us
> > preempt threshold starting at schedule+0x55/0x5a0 and ending at
> > schedule+0x2ed/0x5a0
>
> just to make sure this is not a false positive - is this accompanied by
> ALSA-detected xruns as well? (i suspect it is.)

Yes, here it is:

Aug 9 22:12:48 mindpipe kernel: ALSA /home/rlrevell/cvs/alsa/alsa-driver/alsa-kernel/core/pcm_lib.c:139: XRUN: pcmC0D2c
Aug 9 22:12:48 mindpipe kernel: [dump_stack+23/32] dump_stack+0x17/0x20
Aug 9 22:12:48 mindpipe kernel: [__crc_totalram_pages+1425/2369476] snd_pcm_period_elapsed+0x27b/0x3e0 [snd_pcm]
Aug 9 22:12:48 mindpipe kernel: [__crc_totalram_pages+135447/2369476] snd_emu10k1_interrupt+0xd1/0x3c0 [snd_emu10k1]
Aug 9 22:12:48 mindpipe kernel: [generic_handle_IRQ_event+51/96] generic_handle_IRQ_event+0x33/0x60
Aug 9 22:12:48 mindpipe kernel: [do_IRQ+178/384] do_IRQ+0xb2/0x180
Aug 9 22:12:48 mindpipe kernel: [common_interrupt+24/32] common_interrupt+0x18/0x20
Aug 9 22:12:48 mindpipe kernel: [schedule+727/1440] schedule+0x2d7/0x5a0
Aug 9 22:12:48 mindpipe kernel: [schedule_timeout+158/160] schedule_timeout+0x9e/0xa0
Aug 9 22:12:48 mindpipe kernel: [sys_rt_sigtimedwait+479/736] sys_rt_sigtimedwait+0x1df/0x2e0
Aug 9 22:12:48 mindpipe kernel: [syscall_call+7/11] syscall_call+0x7/0xb

I do not seem to get false positives anymore, IOW, all the traces I send
you are accompanied by an ALSA xrun. I suspect that with a lower
threshold (100us), the overhead from all the printks and stack dumps was
causing one violation to lead to a domino effect.

Lee