Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965966AbXEVQtR (ORCPT ); Tue, 22 May 2007 12:49:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758422AbXEVQtH (ORCPT ); Tue, 22 May 2007 12:49:07 -0400 Received: from zrtps0kp.nortel.com ([47.140.192.56]:46962 "EHLO zrtps0kp.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757071AbXEVQtG (ORCPT ); Tue, 22 May 2007 12:49:06 -0400 Message-ID: <46531EF6.3020204@nortel.com> Date: Tue, 22 May 2007 10:48:54 -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: Ingo Molnar CC: William Lee Irwin III , Dmitry Adamushko , Peter Williams , Linux Kernel Subject: Re: [patch] CFS scheduler, -v12 References: <20070513153853.GA19846@elte.hu> <464A6698.3080400@bigpond.net.au> <20070516063625.GA9058@elte.hu> <464CE8FD.4070205@bigpond.net.au> <20070518071325.GB28702@elte.hu> <464DA61A.4040406@bigpond.net.au> <20070521082926.GH19966@holomorphy.com> <20070521085703.GA18755@elte.hu> In-Reply-To: <20070521085703.GA18755@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 22 May 2007 16:48:58.0860 (UTC) FILETIME=[17E7B2C0:01C79C91] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 992 Lines: 23 Ingo Molnar wrote: > CFS is fair even on SMP. Consider for example the worst-case > 3-tasks-on-2-CPUs workload on a 2-CPU box: > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 2658 mingo 20 0 1580 248 200 R 67 0.0 0:56.30 loop > 2656 mingo 20 0 1580 252 200 R 66 0.0 0:55.55 loop > 2657 mingo 20 0 1576 248 200 R 66 0.0 0:55.24 loop > > 66% of CPU time for each task. The 'TIME+' column shows a 2% spread > between the slowest and the fastest loop after just 1 minute of runtime > (and the spread gets narrower with time). Is there a way in CFS to tune the amount of time over which the load balancer is fair? (Of course there would be some overhead involved.) Chris - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/