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SubjectRe: CFS review
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On Wed, 2007-08-01 at 09:30 +0200, Ingo Molnar wrote:
> * Mike Galbraith <efault@gmx.de> wrote:

> > I haven't been able to reproduce this with any combination of
> > features, and massive_intr tweaked to his work/sleep cycle. I notice
> > he's collecting stats though, and they look funky. Recompiling.
>
> yeah, the posted numbers look most weird, but there's a complete lack of
> any identification of test environment - so we'll need some more word
> >from Roman. Perhaps this was run on some really old box that does not
> have a high-accuracy sched_clock()? The patch below should simulate that
> scenario on 32-bit x86.
>
> Ingo
>
> Index: linux/arch/i386/kernel/tsc.c
> ===================================================================
> --- linux.orig/arch/i386/kernel/tsc.c
> +++ linux/arch/i386/kernel/tsc.c
> @@ -110,7 +110,7 @@ unsigned long long native_sched_clock(vo
> * very important for it to be as fast as the platform
> * can achive it. )
> */
> - if (unlikely(!tsc_enabled && !tsc_unstable))
> +// if (unlikely(!tsc_enabled && !tsc_unstable))
> /* No locking but a rare wrong value is not a big deal: */
> return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
>

Ah, thanks. I noticed that clocksource= went away. I'll test with
stats, with and without jiffies resolution.

-Mike

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