From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: small RPS cache for fragments? Date: Mon, 06 Jun 2011 10:08:52 -0700 Message-ID: <1307380132.8149.2718.camel@tardy> References: <20110517.143342.1566027350038182221.davem@davemloft.net> <20110524.160123.2051949867829317339.davem@davemloft.net> <1306273128.8149.1444.camel@tardy> <20110604.132940.2214949964968775365.davem@davemloft.net> Reply-To: rick.jones2@hp.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: David Miller Return-path: Received: from g4t0016.houston.hp.com ([15.201.24.19]:23267 "EHLO g4t0016.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007Ab1FFRIy (ORCPT ); Mon, 6 Jun 2011 13:08:54 -0400 In-Reply-To: <20110604.132940.2214949964968775365.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 2011-06-04 at 13:29 -0700, David Miller wrote: > From: Rick Jones > Date: Tue, 24 May 2011 14:38:48 -0700 > > > Isn't there still an issue (perhaps small) of traffic being sent through > > a mode-rr bond, either at the origin or somewhere along the way? At the > > origin point will depend on the presence of UFO and whether it is > > propagated up through the bond interface, but as a quick test, I > > disabled TSO, GSO and UFO on four e1000e driven interfaces, bonded them > > mode-rr and ran a netperf UDP_RR test with a 1473 byte request size and > > this is what they looked like at my un-bonded reciever at the other end: > > > > 14:31:01.011370 IP (tos 0x0, ttl 64, id 24960, offset 1480, flags > > [none], proto UDP (17), length 21) > > tardy.local > raj-8510w.local: udp > > 14:31:01.011420 IP (tos 0x0, ttl 64, id 24960, offset 0, flags [+], > > proto UDP (17), length 1500) > > tardy.local.36073 > raj-8510w.local.59951: UDP, length 1473 > > 14:31:01.011514 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto > > UDP (17), length 29) > > raj-8510w.local.59951 > tardy.local.36073: UDP, length 1 > > That's not good behavior, and it's of course going to cause sub-optimal > performance if we do the RPS fragment cache. > > RR bond mode could do something similar, to alleviate this. > > I assume it doesn't do this kind of reordering for TCP. Mode-rr bonding reorders TCP segments all the time. rick