From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752902Ab3AUKaW (ORCPT ); Mon, 21 Jan 2013 05:30:22 -0500 Received: from moutng.kundenserver.de ([212.227.126.171]:58756 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752135Ab3AUKaU (ORCPT ); Mon, 21 Jan 2013 05:30:20 -0500 Message-ID: <1358764210.4994.133.camel@marge.simpson.net> Subject: Re: [RFC PATCH 0/2] sched: simplify the select_task_rq_fair() From: Mike Galbraith To: Michael Wang Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, mingo@kernel.org, a.p.zijlstra@chello.nl Date: Mon, 21 Jan 2013 11:30:10 +0100 In-Reply-To: <1358761496.4994.118.camel@marge.simpson.net> References: <1356588535-23251-1-git-send-email-wangyun@linux.vnet.ibm.com> <50ED384C.1030301@linux.vnet.ibm.com> <1357977704.6796.47.camel@marge.simpson.net> <1357985943.6796.55.camel@marge.simpson.net> <1358155290.5631.19.camel@marge.simpson.net> <50F79256.1010900@linux.vnet.ibm.com> <1358654997.5743.17.camel@marge.simpson.net> <50FCACE3.5000706@linux.vnet.ibm.com> <1358743128.4994.33.camel@marge.simpson.net> <50FCCCF5.30504@linux.vnet.ibm.com> <1358750523.4994.55.camel@marge.simpson.net> <1358752180.4994.65.camel@marge.simpson.net> <50FCF212.3010504@linux.vnet.ibm.com> <1358759355.4994.108.camel@marge.simpson.net> <50FD08E1.8000302@linux.vnet.ibm.com> <1358761496.4994.118.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V02:K0:JgSlJrgOWGY2s4y7zgkKfLUvuHUK+eqcLVKRgJ4mUEB Fjm69CAPB1nSA5OlH1nKMTkym7v72BQWfhrZDI6P4lJIDLrEQ1 1GNuIm5ndLqn2LBdvHYe4pk/fos4vVPVZsrTfSJBrS4QyUCS/K 7vTobqU8ujme9iTtEz4owa/tKkeJiAdxlLXGNZEf2bb/u3Ts5a HM91TpaHJVwOIIIzytHMde/pKoLdsf6oXZIE2GESsKOZoZOAg8 b16K2YXn9C4iyEzNU794HXD7wxbltfFHqWOXiHSTdyRKI8EVPk wqCDbIT94NFqGYyG/WZeAdCmPnkkqTyseG1ThNMVeLg2WdDX/f pjKvpt0rSf8PRg87+xfjTFjLevm/Z7kVQGBfiBuZsqS58bDbQ+ JvYSH49+25o9g== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2013-01-21 at 10:44 +0100, Mike Galbraith wrote: > On Mon, 2013-01-21 at 17:22 +0800, Michael Wang wrote: > > On 01/21/2013 05:09 PM, Mike Galbraith wrote: > > > On Mon, 2013-01-21 at 15:45 +0800, Michael Wang wrote: > > >> On 01/21/2013 03:09 PM, Mike Galbraith wrote: > > >>> On Mon, 2013-01-21 at 07:42 +0100, Mike Galbraith wrote: > > >>>> On Mon, 2013-01-21 at 13:07 +0800, Michael Wang wrote: > > >>> > > >>>>> May be we could try change this back to the old way later, after the aim > > >>>>> 7 test on my server. > > >>>> > > >>>> Yeah, something funny is going on. > > >>> > > >>> Never entering balance path kills the collapse. Asking wake_affine() > > >>> wrt the pull as before, but allowing us to continue should no idle cpu > > >>> be found, still collapsed. So the source of funny behavior is indeed in > > >>> balance_path. > > >> > > >> Below patch based on the patch set could help to avoid enter balance path > > >> if affine_sd could be found, just like the old logical, would you like to > > >> take a try and see whether it could help fix the collapse? > > > > > > No, it does not. > > > > Hmm...what have changed now compared to the old logical? > > What I did earlier to confirm the collapse originates in balance_path is > below. I just retested to confirm. ... And you can add.. if (per_cpu(sd_llc_id, cpu) == per_cpu(sd_llc_id, prev_cpu)) goto unlock; ..before calling select_idle_sibling() the second time to optimize department of redundancy department idle search algorithm ;-) -Mike