Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759201AbXH2Exi (ORCPT ); Wed, 29 Aug 2007 00:53:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750737AbXH2Exb (ORCPT ); Wed, 29 Aug 2007 00:53:31 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:35694 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750781AbXH2Ex3 (ORCPT ); Wed, 29 Aug 2007 00:53:29 -0400 Date: Wed, 29 Aug 2007 06:53:16 +0200 From: Ingo Molnar To: Al Boldi Cc: Linus Torvalds , Peter Zijlstra , Mike Galbraith , Andrew Morton , linux-kernel@vger.kernel.org, Keith Packard Subject: Re: CFS review Message-ID: <20070829045316.GA15064@elte.hu> References: <200708111344.42934.a1426z@gawab.com> <20070828164507.GA2969@elte.hu> <200708290719.24422.a1426z@gawab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200708290719.24422.a1426z@gawab.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0027] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1222 Lines: 30 * Al Boldi wrote: > I have narrowed it down a bit to add_wait_runtime. the scheduler is a red herring here. Could you "strace -ttt -TTT" one of the glxgears instances (and send us the cfs-debug-info.sh output, with CONFIG_SCHED_DEBUG=y and CONFIG_SCHEDSTATS=y as requested before) so that we can have a closer look? i reproduced something similar and there the stall is caused by 1+ second select() delays on the X client<->server socket. The scheduler stats agree with that: se.sleep_max : 2194711437 se.block_max : 0 se.exec_max : 977446 se.wait_max : 1912321 the scheduler itself had a worst-case scheduling delay of 1.9 milliseconds for that glxgears instance (which is perfectly good - in fact - excellent interactivity) - but the task had a maximum sleep time of 2.19 seconds. So the 'glitch' was not caused by the scheduler. 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/