Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275AbXIZJf0 (ORCPT ); Wed, 26 Sep 2007 05:35:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753113AbXIZJfS (ORCPT ); Wed, 26 Sep 2007 05:35:18 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:35081 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752767AbXIZJfQ (ORCPT ); Wed, 26 Sep 2007 05:35:16 -0400 Date: Wed, 26 Sep 2007 11:34:45 +0200 From: Ingo Molnar To: Martin Michlmayr Cc: Srivatsa Vaddagiri , linux-kernel@vger.kernel.org Subject: Re: Network slowdown due to CFS Message-ID: <20070926093445.GA24768@elte.hu> References: <20070926085202.GE3337@deprecation.cyrius.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070926085202.GE3337@deprecation.cyrius.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.5 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: 1476 Lines: 35 * Martin Michlmayr wrote: > I noticed that my network performance has gone down from 2.6.22 > from [ 3] 0.0-10.0 sec 113 MBytes 95.0 Mbits/sec > to [ 3] 0.0-10.0 sec 75.7 MBytes 63.3 Mbits/sec > with 2.6.23-rc1 (and 2.6.23-rc8), as measured with iperf. > > I did a git bisect today and tracked it back to the commit where CFS > was enabled ("sched: cfs core code; apply the CFS core code", > commit dd41f596cda0d7d6e4a8b139ffdfabcefdd46528). I also compiled a > kernel from > git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-devel.git > but things don't improve. > > This is on a Thecus N2100, an ARM (Intel IOP32x) based storage device > with a r8169 card, SATA disks and 512 MB RAM. My config is attached. > > What kind of information can I supply so you can track this down? as a starter, could you boot the sched-devel.git kernel, with CONFIG_SCHED_DEBUG=y and CONFIG_SCHEDSTATS=y enabled and could you run this script while the iperf test is in the middle of its testrun: http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh this will gather a good deal of info about the workload in question. Please send me the resulting debug file. 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/