From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: [PATCH] ifb: add multi-queue support Date: Fri, 13 Nov 2009 09:18:25 +0000 Message-ID: <20091113091825.GA7449@ff.dom.local> References: <412e6f7f0911122216u6880e855g6a15dac29ad6a100@mail.gmail.com> <20091113074508.GA6605@ff.dom.local> <412e6f7f0911130054i7a508a6ah16368f11bdc7353d@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Dumazet , "David S. Miller" , Stephen Hemminger , Patrick McHardy , Tom Herbert , netdev@vger.kernel.org To: Changli Gao Return-path: Received: from mail-fx0-f221.google.com ([209.85.220.221]:42121 "EHLO mail-fx0-f221.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755660AbZKMJS1 (ORCPT ); Fri, 13 Nov 2009 04:18:27 -0500 Received: by fxm21 with SMTP id 21so209581fxm.21 for ; Fri, 13 Nov 2009 01:18:30 -0800 (PST) Content-Disposition: inline In-Reply-To: <412e6f7f0911130054i7a508a6ah16368f11bdc7353d@mail.gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Nov 13, 2009 at 04:54:50PM +0800, Changli Gao wrote: > On Fri, Nov 13, 2009 at 3:45 PM, Jarek Poplawski wrote: > > On 13-11-2009 07:16, Changli Gao wrote: > > > > I don't think so. There would be a lot of code duplication and later > > maintenance problems only because of the scheduling method. The main > > question is to establish if there is really no performance difference > > (which I doubt) - unless Changli can show some tests for various > > setups now. On the other hand, if there is a difference, why keep > > ineffective solution - similar thing should be possible to do in the > > softirq context as well. > > > > So it should not be a big problem to do it a bit messy for some > > testing time. Since we can use separate ->ndo_start_xmit() etc. it > > shouldn't be too messy, I guess. > > > > I have done a simple test. I run a simple program on computer A, which > sends SYN packets with random source ports to Computer B's 80 port (No > socket listens on that port, so tcp reset packets will be sent) in > 90kpps. On computer B, I redirect the traffic to IFB. At the same > time, I ping from B to A to get the RTT between them. I can't see any > difference between the original IFB and my MQ version. They are both: > > CPU idle: 50% > Latency: 0.3-0.4ms, burst 2ms. > I'm mostly concerned with routers doing forwarding with 1Gb or 10Gb NICs (including multiqueue). Alas/happily I don't have such a problem, but can't help you with testing either. Regards, Jarek P.