From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [tbench regression fixes]: digging out smelly deadmen. Date: Fri, 31 Oct 2008 16:56:20 -0700 Message-ID: <20081031165620.7322b0e5@extreme> References: <20081031125713.6c6923de@extreme> <20081031201016.GA4748@ioremap.net> <490B7284.2010003@cosmosbay.com> <20081031.165144.86556444.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: dada1@cosmosbay.com, zbr@ioremap.net, 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 To: David Miller Return-path: Received: from mail.vyatta.com ([76.74.103.46]:48090 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751410AbYJaX42 convert rfc822-to-8bit (ORCPT ); Fri, 31 Oct 2008 19:56:28 -0400 In-Reply-To: <20081031.165144.86556444.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 31 Oct 2008 16:51:44 -0700 (PDT) David Miller wrote: > From: Eric Dumazet > Date: Fri, 31 Oct 2008 22:03:00 +0100 >=20 > > Evgeniy Polyakov a =C3=A9crit : > > > On Fri, Oct 31, 2008 at 12:57:13PM -0700, Stephen Hemminger (shem= minger@vyatta.com) wrote: > > >> Why bother with last_rx at all on loopback. I have been thinkin= g > > >> we should figure out a way to get rid of last_rx all together. I= t 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 th= is > > > 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. > >=20 > > Just to be clear, this change was not meant to be committed. > > It already was rejected by David some years ago (2005, and 2006) > >=20 > > http://www.mail-archive.com/netdev@vger.kernel.org/msg07382.html >=20 > However, I do like Stephen's suggestion that maybe we can get rid of > this ->last_rx thing by encapsulating the logic completely in the > bonding driver. Since bonding driver doesn't actually see the rx packets, that isn't really possible. But it would be possible to change last_rx from a var= iable to an function pointer, so that device's could apply other logic to der= ive the last value. One example would be to keep it per cpu and then take = the maximum.