On Fri, 2007-06-01 at 15:12 +0200, Ingo Molnar wrote:
> * Daniel Walker <[email protected]> wrote:
>
> > On Wed, 2007-05-30 at 19:16 +0200, Peter Zijlstra wrote:
>
> > > I think you are mistaken here; the two are similar but not
> > > identical.
> > >
> > > I see sched_clock() as fast first, accurate second. Whereas the
> > > clocksource thing is accurate first, fast second.
> >
> > This is true .. However, if there is a speed different it's small.
>
> Ugh. Have you ever compared pmtimer (or even hpet) against TSC based
> sched_clock()? What you write is so wrong that it's not even funny. You
> keep repeating this nonsense despite having been told multiple times
> that you are dead wrong.
Yes I have, and your right there is a difference, and a big
difference .. Above I was referring only to the TSC clocksource, since
that's an apples to apples comparison .. I would never compare the TSC
to the acpi_pm, that's no contest ..
The acpi_pm as sched_clock() with hackbench was about %25 slower, the
pit was 10x slower approximately. (I did this months ago.)
Daniel
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