Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753403AbYJaVEX (ORCPT ); Fri, 31 Oct 2008 17:04:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752442AbYJaVEN (ORCPT ); Fri, 31 Oct 2008 17:04:13 -0400 Received: from gw1.cosmosbay.com ([86.65.150.130]:55893 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752381AbYJaVEM convert rfc822-to-8bit (ORCPT ); Fri, 31 Oct 2008 17:04:12 -0400 Message-ID: <490B7284.2010003@cosmosbay.com> Date: Fri, 31 Oct 2008 22:03:00 +0100 From: Eric Dumazet User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 To: Evgeniy Polyakov CC: Stephen Hemminger , David Miller , ilpo.jarvinen@helsinki.fi, rjw@sisk.pl, mingo@elte.hu, s0mbre@tservice.net.ru, a.p.zijlstra@chello.nl, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, efault@gmx.de, akpm@linux-foundation.org Subject: Re: [tbench regression fixes]: digging out smelly deadmen. References: <20081031.005219.141937694.davem@davemloft.net> <20081031.025159.51432990.davem@davemloft.net> <490AE1CD.9040207@cosmosbay.com> <20081031125713.6c6923de@extreme> <20081031201016.GA4748@ioremap.net> In-Reply-To: <20081031201016.GA4748@ioremap.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8BIT X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-1.6 (gw1.cosmosbay.com [0.0.0.0]); Fri, 31 Oct 2008 22:03:06 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1314 Lines: 28 Evgeniy Polyakov a ?crit : > On Fri, Oct 31, 2008 at 12:57:13PM -0700, Stephen Hemminger (shemminger@vyatta.com) wrote: >> Why bother with last_rx at all on loopback. I have been thinking >> we should figure out a way to get rid of last_rx all together. It only >> seems to be used by bonding, and the bonding driver could do the calculation >> in its receive handling. > > Not related to the regression: bug will be just papered out by this > changes. Having bonding on loopback is somewhat strange idea, but still > this kind of changes is an attempt to make a good play in the bad game: > this loopback-only optimization does not fix the problem. > Just to be clear, this change was not meant to be committed. It already was rejected by David some years ago (2005, and 2006) http://www.mail-archive.com/netdev@vger.kernel.org/msg07382.html If you read my mail, I was *only* saying that tbench results can be sensible to cache line ping pongs. tbench is a crazy benchmark, and only is a crazy benchmark. Optimizing linux for tbench sake would be .... crazy ? -- 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/