Return-path: Received: from mail.gmx.net ([213.165.64.20]:42655 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757477AbZJIUHJ (ORCPT ); Fri, 9 Oct 2009 16:07:09 -0400 Subject: Re: [.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU" From: Mike Galbraith To: Frans Pop Cc: Arjan van de Ven , Linux Kernel Mailing List , Ingo Molnar , Peter Zijlstra , linux-wireless@vger.kernel.org In-Reply-To: <200910091827.01774.elendil@planet.nl> References: <200910051500.55875.elendil@planet.nl> <200910082259.35204.elendil@planet.nl> <1255070103.7639.30.camel@marge.simson.net> <200910091827.01774.elendil@planet.nl> Content-Type: text/plain Date: Fri, 09 Oct 2009 22:06:20 +0200 Message-Id: <1255118780.7305.13.camel@marge.simson.net> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 2009-10-09 at 18:27 +0200, Frans Pop wrote: > 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! Thanks for the confirmation (and kind words). -Mike