From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754733AbYE2Cls (ORCPT ); Wed, 28 May 2008 22:41:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750926AbYE2Cli (ORCPT ); Wed, 28 May 2008 22:41:38 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:38110 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750838AbYE2Clh (ORCPT ); Wed, 28 May 2008 22:41:37 -0400 Date: Thu, 29 May 2008 08:20:39 +0530 From: Srivatsa Vaddagiri To: "Chris Friesen" 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? Message-ID: <20080529025039.GA12836@linux.vnet.ibm.com> Reply-To: vatsa@linux.vnet.ibm.com References: <4834B75A.40900@nortel.com> <20080527171528.GD30285@linux.vnet.ibm.com> <483C4F5A.2010104@nortel.com> <20080528163318.GG30285@linux.vnet.ibm.com> <483DA5E7.5050600@nortel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <483DA5E7.5050600@nortel.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 28, 2008 at 12:35:19PM -0600, Chris Friesen wrote: > Srivatsa Vaddagiri wrote: > >> We seem to be skipping the last element in the task list always. In your >> case, the lone task in Group a/b is always skipped because of this. > >> Updated patch (on top of 2.6.26-rc3 + >> http://programming.kicks-ass.net/kernel-patches/sched-smp-group-fixes/) >> below. Pls let me know how it fares! > > Looking much better, but still some fairness issues with more complex > setups. > [snip] > A 10-sec average was better, but we still see errors of 6%: > 2478 72.8% > 2477 64.0% > 2479 63.2% Yes I have observed that the delta from ideal fairness is much more than desirable (although I used to get much better fairness with 2.6.25-rc1. Let me verify and get back). -- Regards, vatsa