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

Scott Wood
2004-07-29T21:01:34Z

On Thu, Jul 29, 2004 at 10:26:30PM +0200, Pavel Machek wrote:
> Well, I do not follow you I guess.
>
> With large-enough number of hardirqs you do no progress at all.
>
> Even if only "sane" number of irqs, if they all decide to hit within one
> getpid(), this getpid is going to take quite long....
> Pavel

Ordinarily, yes. However, if it's a high-priority RT task that does
the getpid(), whose priority is higher than that of the RT tasks,
you'll get at most one hardirq stub per active IRQ number; after
that, the IRQs will be masked until their threads get a chance to be
scheduled.

-Scott