From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753934AbYHRCGV (ORCPT ); Sun, 17 Aug 2008 22:06:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751324AbYHRCGI (ORCPT ); Sun, 17 Aug 2008 22:06:08 -0400 Received: from mga05.intel.com ([192.55.52.89]:11477 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750943AbYHRCGH (ORCPT ); Sun, 17 Aug 2008 22:06:07 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.32,225,1217833200"; d="scan'208";a="371429374" Subject: Re: tbench regression on each kernel release from 2.6.22 -> 2.6.28 From: "Zhang, Yanmin" To: Ilpo =?ISO-8859-1?Q?J=E4rvinen?= Cc: David Miller , cl@linux-foundation.org, Netdev , LKML In-Reply-To: References: <48A086B6.2000901@linux-foundation.org> <20080811.141501.01468546.davem@davemloft.net> Content-Type: text/plain; charset=ISO-8859-1 Date: Mon, 18 Aug 2008 10:05:14 +0800 Message-Id: <1219025114.25933.6.camel@ymzhang> Mime-Version: 1.0 X-Mailer: Evolution 2.21.5 (2.21.5-2.fc9) Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2008-08-12 at 11:13 +0300, Ilpo Järvinen wrote: > On Mon, 11 Aug 2008, David Miller wrote: > > > From: Christoph Lameter > > Date: Mon, 11 Aug 2008 13:36:38 -0500 > > > > > It seems that the network stack becomes slower over time? Here is a list of > > > tbench results with various kernel versions: > > > > > > 2.6.22 3207.77 mb/sec > > > 2.6.24 3185.66 > > > 2.6.25 2848.83 > > > 2.6.26 2706.09 > > > 2.6.27(rc2) 2571.03 > > > > > > And linux-next is: > > > > > > 2.6.28(l-next) 2568.74 > > > > > > It shows that there is still have work to be done on linux-next. Too close to > > > upstream in performance. > > > > > > Note the KT event between 2.6.24 and 2.6.25. Why is that? > > > > Isn't that when some major scheduler changes went in? I'm not blaming > > the scheduler, but rather I'm making the point that there are other > > subsystems in the kernel that the networking interacts with that > > influences performance at such a low level. > > ...IIRC, somebody in the past did even bisect his (probably netperf) > 2.6.24-25 regression to some scheduler change (obviously it might or might > not be related to this case of yours)... I did find much regression with netperf TCP-RR-1/UDP-RR-1/UDP-RR-512. I start 1 serve and 1 client while binding them to a different logical processor in different physical cpu. Comparing with 2.6.22, the regression of TCP-RR-1 on 16-core tigerton is: 2.6.23 6% 2.6.24 6% 2.6.25 9.7% 2.6.26 14.5% 2.6.27-rc1 22% Other regressions on other machines are similar. yanmin