Re: [patch] PPC/PPC64 port of voluntary preempt patch

Scott Wood
2004-08-26T16:48:47Z

On Wed, Aug 25, 2004 at 11:17:32PM -0400, Lee Revell wrote:
> I think Scott may be on to something. There are several reports that P9
> does not work on SMP machines at all - it either doesn't boot, locks up
> the first time there is heavy IRQ activity (starting KDE), or locks up
> as soon as the first RT process is run. This is exactly the behavior
> that would be expected if Scott is correct. See this thread:
>
> http://ccrma-mail.stanford.edu/pipermail/planetccrma/2004-August/005899.html
>
> Does anyone have P9 working on SMP? Fernando, can you see if M5 works
> on SMP? If this works it would seem that the preemptible IRQs are the
> problem.

It worked for me on an SMP G5, but it would depend on which drivers
are used; some use synchronize_irq() more than others.

IIRC, though, M5 didn't have the IO-APIC fixes, so that's not likely
to work well on SMP either.

-Scott