From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753468AbYHLINg (ORCPT ); Tue, 12 Aug 2008 04:13:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751809AbYHLINT (ORCPT ); Tue, 12 Aug 2008 04:13:19 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:48387 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575AbYHLINS (ORCPT ); Tue, 12 Aug 2008 04:13:18 -0400 Date: Tue, 12 Aug 2008 11:13:15 +0300 (EEST) From: "=?ISO-8859-1?Q?Ilpo_J=E4rvinen?=" X-X-Sender: ijjarvin@wrl-59.cs.helsinki.fi To: David Miller cc: cl@linux-foundation.org, Netdev , LKML Subject: Re: tbench regression on each kernel release from 2.6.22 -> 2.6.28 In-Reply-To: <20080811.141501.01468546.davem@davemloft.net> Message-ID: References: <48A086B6.2000901@linux-foundation.org> <20080811.141501.01468546.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.