linux-kernel - [patch 0/2] sched, timers: simplify calc

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Date:	Thu, 14 May 2009 11:21:14 -0000
From:	Thomas Gleixner <tglx@...utronix.de>
To:	LKML <linux-kernel@...r.kernel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Dimitri Sivanich <sivanich@....com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: [patch 0/2] sched,
	timers: simplify calc_load and avoid cpu iteration loop

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

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