From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752354Ab3AXGvY (ORCPT ); Thu, 24 Jan 2013 01:51:24 -0500 Received: from moutng.kundenserver.de ([212.227.17.8]:53683 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278Ab3AXGvQ (ORCPT ); Thu, 24 Jan 2013 01:51:16 -0500 Message-ID: <1359010272.5833.39.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: Thu, 24 Jan 2013 07:51:12 +0100 In-Reply-To: <5100CE1F.7080704@linux.vnet.ibm.com> References: <1356588535-23251-1-git-send-email-wangyun@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> <50FE0ADC.6060701@linux.vnet.ibm.com> <1358841795.5782.255.camel@marge.simpson.net> <50FE5433.1070801@linux.vnet.ibm.com> <1358865692.5782.420.camel@marge.simpson.net> <50FF4EA0.1070000@linux.vnet.ibm.com> <1358915494.5752.46.camel@marge.simpson.net> <50FF7086.4020509@linux.vnet.ibm.com> <1358922520.5752.91.camel@marge.simpson.net> <50FF8CD8.4060105@linux.vnet.ibm.com> <1358929257.5752.109.camel@marge.simp! son.net> <50FF9F92.60202@linux.vnet.ibm.com> <1358930968.5752.123.camel@marge.simpson.net> <50FFA695.6010407@linux.vnet.ibm.com> <1358932694.5752.126.camel@marge.simpson.net> <1358933555.5752.132.camel@marge.simpson.net> <5100CE1F.7080704@linux.vnet.ibm.com> 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:f3P9MSyyM0Sx1aL8JJbZt6Q9wXpm4/PaOFQoZQk/nMG s+ynK+J/IYKuX/9s92UHUVDTGRW3A84Zu/DMsvipxqpt78F7nI R8H9P06N+aI7p0ZmUnx1fmISltiEVl6h0z5qgc7fwKW//2+3DB svDcSMAVUeKZ+URvAXI5UpruZZoefPm3HWzwAbdev3E1RtUl+f XA9AGUuWMV9W17MwaIBEr/GWa33M+im0Ze4eClWanGGezlqJWZ VzXyOw8qwVbjD5nhxBhzHbDigRfBPA98FcbwukdPA2KIHwhhp8 NtTark/G9JVQJ5drKHQ0KGeaRzctk/IKgq6ewMojkJFzhheHO8 DvGwIXfbKig9eGsKN5LOBKsFT/SncdE+fdhO0skK+SQnp/dm92 hKXykMO3wHt1Q== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-01-24 at 14:01 +0800, Michael Wang wrote: > I've enabled WAKE flag on my box like you did, but still can't see > regression, and I've just tested on a power server with 64 cpu, also > failed to reproduce the issue (not compared with virgin yet, but can't > see collapse). I'm not surprised. I'm seeing enough inconsistent crap to come to the conclusion that stock scheduler knobs flat can't be used on a largish box, they're just too preempt-happy, leading to weird crap. My 2 missing nodes came back, and the very same kernel that highly repeatably collapsed with 2 nodes does not with 4 nodes, and 2 nodes does not collapse with only preemption knob tweaking, and that's bullshit. Virgin shows instability in the mid-range, make a tiny tweak that should have little if any effect there, and that instability vanishes entirely. Test runs are not consistent enough boot to boot etc etc. Either stock knobs suck on NUMA boxen, or this box is possessed. -Mike