Return-path: Received: from Cpsmtpm-eml107.kpnxchange.com ([195.121.3.11]:65271 "EHLO CPSMTPM-EML107.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933569AbZJIQ1j (ORCPT ); Fri, 9 Oct 2009 12:27:39 -0400 From: Frans Pop To: Mike Galbraith Subject: Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU" Date: Fri, 9 Oct 2009 18:27:00 +0200 Cc: Arjan van de Ven , Linux Kernel Mailing List , Ingo Molnar , Peter Zijlstra , linux-wireless@vger.kernel.org References: <200910051500.55875.elendil@planet.nl> <200910082259.35204.elendil@planet.nl> <1255070103.7639.30.camel@marge.simson.net> In-Reply-To: <1255070103.7639.30.camel@marge.simson.net> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Message-Id: <200910091827.01774.elendil@planet.nl> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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