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Date: Fri, 15 May 2009 07:23:08 -0500
From: Dimitri Sivanich <sivanich@sgi.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [patch 0/2] sched, timers: simplify calc_load and avoid cpu
	iteration loop
Message-ID: <20090515122308.GA11465@sgi.com>
References: <20090514105915.973318588@linutronix.de>
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Acked-by: Dimitri Sivanich <sivanich@sgi.com>

On Thu, May 14, 2009 at 11:21:14AM -0000, Thomas Gleixner wrote:
> 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
>