From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758794AbYE0SOI (ORCPT ); Tue, 27 May 2008 14:14:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756775AbYE0SN4 (ORCPT ); Tue, 27 May 2008 14:13:56 -0400 Received: from zcars04f.nortel.com ([47.129.242.57]:61802 "EHLO zcars04f.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756342AbYE0SNz (ORCPT ); Tue, 27 May 2008 14:13:55 -0400 Message-ID: <483C4F5A.2010104@nortel.com> Date: Tue, 27 May 2008 12:13:46 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: vatsa@linux.vnet.ibm.com CC: linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, pj@sgi.com, Balbir Singh , aneesh.kumar@linux.vnet.ibm.com, dhaval@linux.vnet.ibm.com Subject: Re: fair group scheduler not so fair? References: <4834B75A.40900@nortel.com> <20080527171528.GD30285@linux.vnet.ibm.com> In-Reply-To: <20080527171528.GD30285@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 27 May 2008 18:13:50.0814 (UTC) FILETIME=[6A3377E0:01C8C025] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Srivatsa Vaddagiri wrote: > But first, note that Groups "a" and "b" share bandwidth with all tasks > in /dev/cgroup/tasks. Ah, good point. I've switched over to your group setup for testing. > The following experimental patch (on top of 2.6.26-rc3 + > http://programming.kicks-ass.net/kernel-patches/sched-smp-group-fixes/) seems > to fix the problem. > Can you check if this makes a difference for you as well? Initially it looked promising. I put pid 2498 in group A, and pids 2499 and 2500 in group B. 2498 got basically a full cpu, and the other two got 50% each. However, I then moved pid 2499 from group B to group A, and the system got stuck in the following behaviour: 2498 cfriesen 20 0 3800 392 336 R 99.7 0.0 3:00.22 cat 2500 cfriesen 20 0 3800 392 336 R 66.7 0.0 1:39.10 cat 2499 cfriesen 20 0 3800 392 336 R 33.0 0.0 1:24.31 cat I reproduced this a number of times. Chris