Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757002AbXIZL3t (ORCPT ); Wed, 26 Sep 2007 07:29:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754273AbXIZL3m (ORCPT ); Wed, 26 Sep 2007 07:29:42 -0400 Received: from sorrow.cyrius.com ([65.19.161.204]:4253 "EHLO sorrow.cyrius.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754070AbXIZL3l (ORCPT ); Wed, 26 Sep 2007 07:29:41 -0400 Date: Wed, 26 Sep 2007 13:29:19 +0200 From: Martin Michlmayr To: Ingo Molnar Cc: Mike Galbraith , Srivatsa Vaddagiri , linux-kernel@vger.kernel.org, Stephen Hemminger Subject: Re: Network slowdown due to CFS Message-ID: <20070926112919.GN3337@deprecation.cyrius.com> References: <20070926085202.GE3337@deprecation.cyrius.com> <1190802208.7318.5.camel@Homer.simpson.net> <20070926104814.GM3337@deprecation.cyrius.com> <20070926112137.GA13876@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070926112137.GA13876@elte.hu> User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 943 Lines: 26 * Ingo Molnar [2007-09-26 13:21]: > > > I noticed on the iperf website a patch which contains sched_yield(). > > > http://dast.nlanr.net/Projects/Iperf2.0/patch-iperf-linux-2.6.21.txt > > great! Could you try this too: > echo 1 > /proc/sys/kernel/sched_compat_yield > > does it fix iperf performance too (with the yield patch applied to > iperf)? Yes, this gives me good performance too. > I think the real fix would be for iperf to use blocking network IO > though, or maybe to use a POSIX mutex or POSIX semaphores. So it's definitely not a bug in the kernel, only in iperf? (CCing Stephen Hemminger who wrote the iperf patch.) -- Martin Michlmayr http://www.cyrius.com/ - 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/