Re: [PATCH] i386 Time: Avoid PIT SMP lockups

From: Andi Kleen
Date: Wed Oct 18 2006 - 12:28:06 EST


"Maciej W. Rozycki" <macro@xxxxxxxxxxxxxx> writes:

> On Wed, 11 Oct 2006, Andrew Morton wrote:
>
> > So this patch has the potential to screw up people who have 2-way or 4-way,
> > no hpet/pm-timer and dodgy TSCs.
>
> Note that all APIC-based SMP systems (even these rare i486 beasts) by
> definition do have local APIC timers, one per CPU, with a reasonable
> resolution which could likely be used instead.

It wouldn't work on dual core laptop chipsets which support C3 and where
the APIC timer stops during C3.

I had a apicrunsmaintimer option for some time on x86-64 but it broke
on a few other non laptop machines for unknown reasons too, so I cannot
really recommend it.

-Andi
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