From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751114AbVHUVPv (ORCPT ); Sun, 21 Aug 2005 17:15:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751113AbVHUVPv (ORCPT ); Sun, 21 Aug 2005 17:15:51 -0400 Received: from zeus1.kernel.org ([204.152.191.4]:21194 "EHLO zeus1.kernel.org") by vger.kernel.org with ESMTP id S1751109AbVHUVPu (ORCPT ); Sun, 21 Aug 2005 17:15:50 -0400 Date: Sun, 21 Aug 2005 12:47:46 -0700 From: Andrew Morton To: danial_thom@yahoo.com Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: 2.6.12 Performance problems Message-Id: <20050821124746.5d57203f.akpm@osdl.org> In-Reply-To: <20050821154654.63788.qmail@web33303.mail.mud.yahoo.com> References: <20050821154654.63788.qmail@web33303.mail.mud.yahoo.com> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Danial Thom wrote: > > I just started fiddling with 2.6.12, and there > seems to be a big drop-off in performance from > 2.4.x in terms of networking on a uniprocessor > system. Just bridging packets through the > machine, 2.6.12 starts dropping packets at > ~100Kpps, whereas 2.4.x doesn't start dropping > until over 350Kpps on the same hardware (2.0Ghz > Opteron with e1000 driver). This is pitiful > prformance for this hardware. I've > increased the rx ring in the e1000 driver to 512 > with little change (interrupt moderation is set > to 8000 Ints/second). Has "tuning" for MP > destroyed UP performance altogether, or is there > some tuning parameter that could make a 4-fold > difference? All debugging is off and there are > no messages on the console or in the error logs. > The kernel is the standard kernel.org dowload > config with SMP turned off and the intel ethernet > card drivers as modules without any other > changes, which is exactly the config for my 2.4 > kernels. > (added netdev to cc)