Re: [PATCH] scheduler: fix x86 regression in native_sched_clock

From: Ingo Molnar
Date: Fri Dec 07 2007 - 12:58:42 EST



* Guillaume Chazarain <guichaz@xxxxxxxx> wrote:

> Le Fri, 7 Dec 2007 15:54:18 +0100,
> Ingo Molnar <mingo@xxxxxxx> a écrit :
>
> > This is a version that
> > is supposed fix all known aspects of TSC and frequency-change
> > weirdnesses.
>
> Tested it with frequency changes, the clock is as smooth as I like it
> :-)

ok, great :-)

> The only remaining sched_clock user in need of conversion seems to be
> lockdep.

yeah - for CONFIG_LOCKSTAT - but that needs to be done even more
carefully, due to rq->lock being lockdep-checked. We can perhaps try a
lock-less cpu_clock() version - other CPUs are not supposed to update
rq->clock.

> Great work.

thanks. I do get the impression that most of this can/should wait until
2.6.25. The patches look quite dangerous.

Ingo
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