Messages in this thread | | | Date | Mon, 12 Jul 2004 17:08:44 -0700 | From | Andrew Morton <> | Subject | Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch |
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Paul Davis <paul@linuxaudiosystems.com> 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. >
We can usually tell that from the trace. If it points up into a busy piece of code then it's pretty obvious what's happening. If the trace is due to a long irq-off time then it will point up into the offending local_irq_enable().
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