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Date: Thu, 12 Apr 2007 10:41:51 -0700
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Andi Kleen <ak@novell.com>
CC: Andrew Morton <akpm@linux-foundation.org>,
       Daniel Walker <dwalker@mvista.com>, linux-kernel@vger.kernel.org,
       johnstul@us.ibm.com, tglx@linutronix.de
Subject: Re: [PATCH] i386 tsc: remove xtime_lock'ing around cpufreq notifier
References: <20070411162904.232696302@mvista.com> <200704121136.03098.ak@novell.com> <20070412092348.70a4de05.akpm@linux-foundation.org> <200704121845.39961.ak@novell.com>
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Andi Kleen wrote:
> Ok. I think it's better to just fix sched_clock() again than to
> add another one.  I can probably
> eliminate the ktime_get() and use something based on jiffies. That will
> be inaccurate for the instable case of course.
>
> I will do that later today.

sched_clock seems a bit weird to use.  In the pv_ops world, it only
counts unstolen time, and it is therefore inherently per-cpu.  The
timestamps should be at least system-wide monotonic.

    J