Date: Fri, 10 Aug 2007 10:12:12 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: paulmck@linux.vnet.ibm.com
Cc: Adrian Bunk <bunk@kernel.org>, Josh Triplett <josh@kernel.org>,
       linux-kernel@vger.kernel.org
Subject: Re: 2.6.23-rc2-mm1: rcutorture xtime usage
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On Fri, 10 Aug 2007 08:12:08 -0700 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:

> > One used to use sched_clock() for this, then get frowned at.  Now we
> > have cpu_clock()...
> 
> Hmmm...  And cpu_clock() is not in 2.6.22, so must appear in some later
> release.  Which means that the rate of API change in this area is a
> bit high, so I should avoid it like the plague.

eh, it's been there for weeks.  It is dust-encrusted.

>  Therefore, I should
> look for some other convenient source of entropy.
> 
> One convenient source would the per-CPU statistics that rcutorture
> maintains.  Of course, a given CPU's RNG is nearly in lock-step with
> its own statistics, but not with the adjacent CPU's statistics...
> 
> I will send a patch.

Please use cpu_clock().  It ain't going away.
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