From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758630AbZBLLFk (ORCPT ); Thu, 12 Feb 2009 06:05:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756637AbZBLLFc (ORCPT ); Thu, 12 Feb 2009 06:05:32 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:40813 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750991AbZBLLFa (ORCPT ); Thu, 12 Feb 2009 06:05:30 -0500 Date: Thu, 12 Feb 2009 12:05:00 +0100 From: Ingo Molnar To: "Zhang, Yanmin" Cc: Peter Zijlstra , Lin Ming , Mike Galbraith , "tglx@linutronix.de" , "oleg@redhat.com" , "linux-kernel@vger.kernel.org" , "seto.hidetoshi@jp.fujitsu.com" Subject: Re: [PATCH 0/2] fix the itimer regression (BZ 12618) Message-ID: <20090212110500.GB23665@elte.hu> References: <20090205112414.104100700@chello.nl> <20090205120608.GB8799@elte.hu> <1233895919.2604.323.camel@ymzhang> <20090206151832.GL18368@elte.hu> <1234161961.5991.41.camel@minggr.sh.intel.com> <20090209214723.GA2664@elte.hu> <1234270044.23438.7.camel@twins> <1234318148.2604.370.camel@ymzhang> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1234318148.2604.370.camel@ymzhang> 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 * Zhang, Yanmin wrote: > On Tue, 2009-02-10 at 13:47 +0100, Peter Zijlstra wrote: > > On Mon, 2009-02-09 at 22:47 +0100, Ingo Molnar wrote: > > > * Lin Ming wrote: > > > > > > > On Fri, 2009-02-06 at 23:18 +0800, Ingo Molnar wrote: > > > > > * Zhang, Yanmin wrote: > > > > > > > > > > > On Thu, 2009-02-05 at 13:06 +0100, Ingo Molnar wrote: > > > > > > > * Peter Zijlstra wrote: > > > > > > > > > > > > > > > This should hopefully address all the itimer borkage. > > > > > > > > > > > > > > Applied to tip:timers/urgent, thanks Peter! > > > > > > > > > > > > > > Yanmin: could you check hacbench_pth with latest tip/master, do > > > > > > > these fixes resolve that 3% regression you reported? > > > > > > > > > > > > Lin Ming tested it and hackbench_pth/volanoMark regression all disappear. > > > > > > But oltp has a regression. We think oltp new regression isn't related to > > > > > > the patch. Ming is investigating it. > > > > > > > > > > Potential suspects for oltp regression would be: > > > > > > > > > > 3d39870: sched_rt: don't use first_cpu on cpumask created with cpumask_and > > > > > a571bbe: sched: fix buddie group latency > > > > > a9f3e2b: sched: clear buddies more aggressively > > > > > 1596e29: sched: symmetric sync vs avg_overlap > > > > > d942fb6: sched: fix sync wakeups > > > > > > > > I tested the latest tip-master branch. > > > > After reverting "d942fb6: sched: fix sync wakeups", the oltp regression > > > > on the 8cores Stockley machine is mostly fixed. > > > > > > > > On another 4*4 cores Tigerton machine, oltp has more than 10% regression > > > > with 2.6.29-rc4 compared with 2.6.29-rc3. > > > > > > ok, that commit needs fixed or reverted. Peter, Mike? > > > > Yanmin, is that tigerton regression also due to the sync changes? > Yes. > > > > > That is, if you revert both d942fb6 and 1596e29, does it get back to > > -rc3 state, > Yes. > > > or is the tigerton regression due to something else? > > This isn't quite clear to me. > > > > Ingo, if that is the case, I'm fine with reverting those changes for > > now, and have another look at them later on -- preferably when someone > > ships me a 4*4 machine so I can validate :-) > 2*4 stoakley has the similiar regression. To find potential scalability issues, > I run sysbench+mysql(oltp) with many thread numbers, such like 8,12,16,32,64,128, > then get an average value. FYI, in Linus's latest tree (v2.6.29-rc4-175-gb578f3f or later), all the scheduler related performance regressions should be addressed. Could you please double-check that there's no performance regression remaining? Thanks, Ingo