Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760427AbXEVUPg (ORCPT ); Tue, 22 May 2007 16:15:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757147AbXEVUPa (ORCPT ); Tue, 22 May 2007 16:15:30 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:55143 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756996AbXEVUP3 (ORCPT ); Tue, 22 May 2007 16:15:29 -0400 Date: Tue, 22 May 2007 22:15:18 +0200 From: Ingo Molnar To: Chris Friesen Cc: William Lee Irwin III , Dmitry Adamushko , Peter Williams , Linux Kernel Subject: Re: [patch] CFS scheduler, -v12 Message-ID: <20070522201518.GC6113@elte.hu> 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> <46531EF6.3020204@nortel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46531EF6.3020204@nortel.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1190 Lines: 29 * Chris Friesen wrote: > 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.) it should be fair pretty fast (see the 10 seconds run of massive_intr) - so it's not 1 minute (if you were worried about that). Ingo - 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/