Re: mm snapshot broken-out-2007-04-25-02-49.tar.gz uploaded

[Michal Piotrowski]

On 25/04/07, Andi Kleen <ak@xxxxxxx> wrote:
> On Wednesday 25 April 2007 22:42:44 Jeremy Fitzhardinge wrote:
> > Michal Piotrowski wrote:
> > > Timing information is broken
> > >
> >
> > This looks like Andi's sched_clock stuff hitting: it returns an
> > inherently per-cpu result, so using it for printk timestamps isn't very
> > useful.
>
> It should actually roughly work. There can be some drift, but there shouldn't
> be that much error. All CPUs should tick at roughly the same rate because
> it's scaled to nanoseconds
>
> If the drift is a big issue it would also be possible to resync every minute
> or so, but I haven't implemented that.
>
> There will be always some minor monotonicities because it won't try
> to stop the CPU from reordering instructions.
>
> I don't know why it is that off in your case.

Maybe because it's P4 HT?

Regards,
Michal

--
Michal K. K. Piotrowski
LTG - Linux Testers Group (PL)
(http://www.stardust.webpages.pl/ltg/)
LTG - Linux Testers Group (EN)
(http://www.stardust.webpages.pl/linux_testers_group_en/)
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