Re: [patch] voluntary-preempt-2.6.8-rc2-M5

[Takashi Iwai]

At Fri, 30 Jul 2004 18:54:39 -0400,
Lee Revell wrote:
> 
> On Fri, 2004-07-30 at 02:44, Ingo Molnar wrote:
> > * Lee Revell <rlrevell@xxxxxxxxxxx> wrote:
> > 
> > > After running jackd with L2 all night, the only repeated XRUN was this
> > > one:
> > > 
> > > ALSA /home/rlrevell/cvs/alsa/alsa-driver/alsa-kernel/core/pcm_lib.c:139: XRUN: pcmC0D2c
> > >  [<c01066a7>] dump_stack+0x17/0x20
> > >  [<de93d54b>] snd_pcm_period_elapsed+0x27b/0x3e0 [snd_pcm]
> > >  [<de979211>] snd_emu10k1_interrupt+0xd1/0x3c0 [snd_emu10k1]
> > >  [<c01078d7>] handle_IRQ_event+0x47/0x90
> > >  [<c0107e93>] do_IRQ+0xe3/0x1b0
> > >  [<c0106268>] common_interrupt+0x18/0x20
> > >  [<c0146771>] add_to_swap+0x21/0xc0
> > >  [<c0139446>] shrink_list+0x156/0x4b0
> > >  [<c01398ed>] shrink_cache+0x14d/0x370
> > >  [<c013a118>] shrink_zone+0xa8/0xf0
> > >  [<c013a4ee>] balance_pgdat+0x1be/0x220
> > >  [<c013a5f9>] kswapd+0xa9/0xb0
> > >  [<c0104395>] kernel_thread_helper+0x5/0x10
> > > 
> > > This produced a few ~2ms XRUNs.  The shrink_zone -> shrink_cache ->
> > > shrink_list is a recurring motif.
> > > 
> > > Is this addressed in M2?
> > 
> > not yet. I havent seen this latency yet, nor are there any immediately
> > clear clues in the xrun logs you sent. (it would still be nice to check
> > out -M2, to see whether with all those configurability changes it
> > matches the latencies of L2+your-irq.c-hack.)
> 
> I discovered that a few of the XRUN traces were spurious - jackd
> apparently does something while stopping and starting that produces an
> XRUN trace but that jackd does not consider an error.  I will fix this
> in jackd.  The msync() related XRUN triggered by apt-get is definitely
> real.

Yes.  There is a bogus report at stopping (snd_pcm_drain is called).
It was fixed in the recent ALSA cvs tree, but seems not propagated to
bk yet...


Takashi
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