Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758688AbXEQTYB (ORCPT ); Thu, 17 May 2007 15:24:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756856AbXEQTXx (ORCPT ); Thu, 17 May 2007 15:23:53 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:44251 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756651AbXEQTXx (ORCPT ); Thu, 17 May 2007 15:23:53 -0400 Date: Thu, 17 May 2007 21:23:43 +0200 From: Ingo Molnar To: =?iso-8859-1?B?VPZy9ms=?= Edvin Cc: mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: CFS Scheduler and real-time tasks Message-ID: <20070517192343.GA24249@elte.hu> References: <4354d3270705171214v25bc4834t5e28a08649761e91@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4354d3270705171214v25bc4834t5e28a08649761e91@mail.gmail.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=3.0.3 -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: 851 Lines: 23 * T?r?k Edvin wrote: > Is there something I am doing wrong, or is the precision decrease > expected, when running real-time tasks too? yeah: real-time tasks are ueber-tasks that just get all CPU time immediately. I guess we could make SCHED_RR be covered by CFS accounting eventually. > Very precise indeed, the default scheduler produces lots of different > timings there. note: you ran it on a dual-core system and the SMP load-balancer needs time to gain precision in the non-RT test - so i'd suggest to test it much longer than 10 seconds: 300 seconds at least. 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/