Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753318AbYHRHxj (ORCPT ); Mon, 18 Aug 2008 03:53:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751484AbYHRHx2 (ORCPT ); Mon, 18 Aug 2008 03:53:28 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:46176 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966AbYHRHx1 (ORCPT ); Mon, 18 Aug 2008 03:53:27 -0400 Date: Mon, 18 Aug 2008 10:53:25 +0300 (EEST) From: "=?ISO-8859-1?Q?Ilpo_J=E4rvinen?=" X-X-Sender: ijjarvin@wrl-59.cs.helsinki.fi To: "Zhang, Yanmin" cc: David Miller , cl@linux-foundation.org, Netdev , LKML Subject: Re: tbench regression on each kernel release from 2.6.22 -> 2.6.28 In-Reply-To: <1219025114.25933.6.camel@ymzhang> Message-ID: References: <48A086B6.2000901@linux-foundation.org> <20080811.141501.01468546.davem@davemloft.net> <1219025114.25933.6.camel@ymzhang> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-696208474-1947864013-1219046005=:23854" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2680 Lines: 72 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. ---696208474-1947864013-1219046005=:23854 Content-Type: TEXT/PLAIN; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT On Mon, 18 Aug 2008, Zhang, Yanmin wrote: > > On Tue, 2008-08-12 at 11:13 +0300, Ilpo J?rvinen 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. I btw reorganized tcp_sock for 2.6.26, it shouldn't cause this but it's not always obvious what even a small change in field ordering does for performance (it's b79eeeb9e48457579cb742cd02e162fcd673c4a3 in case you want to check that). Also, there was this 83f36f3f35f4f83fa346bfff58a5deabc78370e5 fix to current -rcs but I guess it might not be that significant in your case (but I don't know well enough :-)). -- i. ---696208474-1947864013-1219046005=:23854-- -- 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/