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Subject: Re: 'global' rq->clock (was Re: Horrendous Audio Stutter - current
	git)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Guillaume Chazarain <guichaz@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>, Frans Pop <elendil@planet.nl>,
       Parag Warudkar <parag.warudkar@gmail.com>, Ingo Molnar <mingo@elte.hu>,
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Date: Fri, 02 May 2008 22:46:05 +0200
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On Fri, 2008-05-02 at 22:38 +0200, Guillaume Chazarain wrote:
> On Fri, May 2, 2008 at 9:56 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> >  Let me try and come up with something slightly less horrible
> 
> Does this obsolete Ingo's "sched: make cpu_clock() globally synchronous"?
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=27ec4407790d075c325e1f4da0a19c56953cce23
> 
> My laptop is UP, so I cannot test this :-(


It doesn't, I'm just throwing around code/ideas.

We should probably come up with some clock lib that builds the various
clocks: rq->clock and cpu_clock() from sched_clock() depending on some
architecture supplied hints.

We can toss most of this code on archs like power64, sparc64 and s390x
which have stable clocks. It just seems wrong to do all this on these
archs, but don't have much choice on x86.