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

Ingo Molnar
2004-07-23T05:47:47Z

* Nick Piggin <nickpiggin@yahoo.com.au> wrote:

> >this doesnt work either: once we've committed ourselves to do an
> >'immediate' softirq processing pass we are risking latencies. We cannot
> >preempt the idle task while it's processing softirqs the same way we can
> >do the lock-break if they are always deferred.
> >
>
> It is a preempt off region no matter where it is run. I don't see how
> moving it to ksoftirqd can shorten that time any further.

look at my latest patches to see how it's done. We can preempt softirq
handlers via lock-break methods. The same method doesnt work in the idle
thread. With this method i've reduced worst-case softirq latencies from
~2-4 msecs to 100-200 usecs on a 2GHz x86 box.

Ingo