From: Frans Pop <elendil@planet.nl>
To: Mike Galbraith <efault@gmx.de>
Subject: Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU"
Date: Fri, 9 Oct 2009 18:27:00 +0200
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Cc: Arjan van de Ven <arjan@infradead.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
       linux-wireless@vger.kernel.org
References: <200910051500.55875.elendil@planet.nl> <200910082259.35204.elendil@planet.nl> <1255070103.7639.30.camel@marge.simson.net>
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On Friday 09 October 2009, Mike Galbraith wrote:
> sched: update the clock of runqueue select_task_rq() selected.
>
> In try_to_wake_up(), we update the runqueue clock, but select_task_rq()
> may select a different runqueue than the one we updated, leaving the new
> runqueue's clock stale for a bit.
>
> This patch cures occasional huge latencies reported by latencytop when
> coming out of idle on a mostly idle NO_HZ box.

This patch (without Arjan's previous one applied) also fixes my latency 
issues. Nice work!

Cheers,
FJP
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