Re: [patch] i386, numaq: enable TSCs again

[Dave Hansen]

On Fri, 2007-05-25 at 10:41 +0200, Ingo Molnar wrote:
> * William Lee Irwin III <wli@xxxxxxxxxxxxxx> 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

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/