linux-kernel - Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU"

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Date:	Fri, 9 Oct 2009 18:27:00 +0200
From:	Frans Pop <elendil@...net.nl>
To:	Mike Galbraith <efault@....de>
Cc:	Arjan van de Ven <arjan@...radead.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-wireless@...r.kernel.org
Subject: Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU"

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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