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SubjectRe: [patch] i386, numaq: enable TSCs again
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On Fri, 2007-05-25 at 10:41 +0200, Ingo Molnar wrote:
> * William Lee Irwin III <wli@holomorphy.com> wrote:
> > > yes, that's what i meant under 'slightly async'. Some AMD CPUs are
> > > like that too and sched_clock() now handles that fine. So we should
> > > try my patch.
> >
> > Sorry, then. I took slight to mean something else. In any event I was
> > only quantifying things. I've no opinion whatsoever on the impact of
> > the code on NUMA-Q, only some recall of its operating characteristics.
>
> there's no need to apologize at all! Thanks for reminding us about the
> time-scale and nature of the TSC drift on NUMAQ. I was worried that
> maybe the TSC was totally unusable for some reason - but that's
> fortunately not the case. So we now have one quirk less, hopefully :-)

Last I remember, it was totally useless for timekeeping, but was useful
for cpu-local time measurements.

John, it's still useless for time, right? Does sched_clock() really fix
it?

-- Dave

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