From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753006AbYHKLnn (ORCPT ); Mon, 11 Aug 2008 07:43:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751513AbYHKLng (ORCPT ); Mon, 11 Aug 2008 07:43:36 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:52405 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751499AbYHKLnf (ORCPT ); Mon, 11 Aug 2008 07:43:35 -0400 Date: Mon, 11 Aug 2008 13:43:24 +0200 From: Ingo Molnar To: Mike Galbraith Cc: LKML , Peter Zijlstra , Gregory Haskins Subject: Re: [revert] mysql+oltp regression Message-ID: <20080811114324.GA23529@elte.hu> References: <1218454322.25098.24.camel@marge.simson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1218454322.25098.24.camel@marge.simson.net> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Mike Galbraith wrote: > Greetings, > > During regression testing of tip/sched/clock fixes, a regression in > low client count throughput turned up, which I traced this back to the > commit below. I don't see anything wrong with it, but suspect that it > is preventing client/server pairs from staying together on the same > CPU as buddies, which mysql definitely likes quite a lot. (I suspect > that this is the case, because I've seen this same performance curve > while tinkering with wakeup affinity and breaking it all to pieces;) > > Changelog and test results below in case nobody sees a problem with > the commit itself. i've applied your fix to tip/sched/urgent for the time being, thanks Mike for tracking it down. We can re-try newer iterations of Greg's patch in tip/sched/devel. Ingo