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Message-Id: <20090514105915.973318588@linutronix.de>
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Date: Thu, 14 May 2009 11:21:14 -0000
From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Dimitri Sivanich <sivanich@sgi.com>,
       Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>
Subject: [patch 0/2] sched,
	timers: simplify calc_load and avoid cpu iteration loop
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Dimitri Sivanich pointed out that calc_load iterates over all online
CPUs under xtime lock which can cause long latencies on large SMP
systems.

The following patch series removes the iteration loop and lets
scheduler_tick() on each CPU update the number of active tasks. The
calc_load() function just uses this variable and updates avenrun from
do_timer().

Dimitri, can you please test run this on one of your large machines ?

Thanks,

	tglx