Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch

[Takashi Iwai <tiwai@suse.de>]

At Mon, 12 Jul 2004 20:01:51 -0400,
Paul Davis wrote:
> 
> >OK, thanks.  The problem areas there are the timer-based route cache
> >flushing and reiserfs.
> >
> >We can probably fix the route caceh thing by rescheduling the timer after
> >having handled 1000 routes or whatever, although I do wonder if this is a
> >thing we really need to bother about - what else was that machine up to?
> 
> i have one concern about this that i talked to takashi about when we
> were in bordeaux. it seems to me that the ALSA xrun debug stuff is
> measuring things when the interrupt handler for the ALSA device
> executes and detects an xrun. if the handler itself was delayed, then
> the stack trace for its execution doesn't or might not show what
> caused the delay. this means, perhaps, that we need to be rather
> careful interpreting these traces.

Well, it can catch up too long critical sections in most cases,
although it cannot measure the latency to wake up the audio thread.
So, the detection can't be 100% guaranteed.


Takashi