Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935760Ab3DJIv1 (ORCPT ); Wed, 10 Apr 2013 04:51:27 -0400 Received: from merlin.infradead.org ([205.233.59.134]:49578 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088Ab3DJIv0 (ORCPT ); Wed, 10 Apr 2013 04:51:26 -0400 Message-ID: <1365583873.30071.31.camel@laptop> Subject: Re: [PATCH] sched: wake-affine throttle From: Peter Zijlstra To: Michael Wang Cc: LKML , Ingo Molnar , Mike Galbraith , Alex Shi , Namhyung Kim , Paul Turner , Andrew Morton , "Nikunj A. Dadhania" , Ram Pai Date: Wed, 10 Apr 2013 10:51:13 +0200 In-Reply-To: <5164DCE7.8080906@linux.vnet.ibm.com> References: <5164DCE7.8080906@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 646 Lines: 18 On Wed, 2013-04-10 at 11:30 +0800, Michael Wang wrote: > | 15 GB | 32 | 35918 | | 37632 | +4.77% | 47923 | +33.42% | > 52241 | +45.45% So I don't get this... is wake_affine() once every milisecond _that_ expensive? Seeing we get a 45%!! improvement out of once every 100ms that would mean we're like spending 1/3rd of our time in wake_affine()? that's preposterous. So what's happening? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/