From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755704Ab3AFCcQ (ORCPT ); Sat, 5 Jan 2013 21:32:16 -0500 Received: from 1wt.eu ([62.212.114.60]:37521 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755300Ab3AFCcM (ORCPT ); Sat, 5 Jan 2013 21:32:12 -0500 Date: Sun, 6 Jan 2013 03:32:06 +0100 From: Willy Tarreau To: Eric Dumazet Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Major network performance regression in 3.7 Message-ID: <20130106023206.GX16031@1wt.eu> References: <20130105232913.GQ16031@1wt.eu> <1357430523.1678.4901.camel@edumazet-glaptop> <20130106005053.GS16031@1wt.eu> <1357435276.1678.5067.camel@edumazet-glaptop> <20130106013027.GV16031@1wt.eu> <1357436430.1678.5111.camel@edumazet-glaptop> <1357437086.1678.5135.camel@edumazet-glaptop> <1357438591.1678.5205.camel@edumazet-glaptop> <20130106021824.GW16031@1wt.eu> <1357438933.1678.5223.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1357438933.1678.5223.camel@edumazet-glaptop> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 05, 2013 at 06:22:13PM -0800, Eric Dumazet wrote: > On Sun, 2013-01-06 at 03:18 +0100, Willy Tarreau wrote: > > On Sat, Jan 05, 2013 at 06:16:31PM -0800, Eric Dumazet wrote: > > > On Sat, 2013-01-05 at 17:51 -0800, Eric Dumazet wrote: > > > > On Sat, 2013-01-05 at 17:40 -0800, Eric Dumazet wrote: > > > > > On Sun, 2013-01-06 at 02:30 +0100, Willy Tarreau wrote: > > > > > > > > > > > Ah interesting because these were some of the mm patches that I had > > > > > > tried to revert. > > > > > > > > > > Hmm, or we should fix __skb_splice_bits() > > > > > > > > > > I'll send a patch. > > > > > > > > > > > > > Could you try the following ? > > > > > > Or more exactly... > > > > The first one did not change a iota unfortunately. I'm about to > > spot the commit causing the loopback regression. It's a few patches > > before the first one you pointed. It's almost finished and I test > > your patch below immediately after. > > I bet you are going to find commit > 69b08f62e17439ee3d436faf0b9a7ca6fffb78db > (net: use bigger pages in __netdev_alloc_frag ) > > Am I wrong ? Yes this time you guessed wrong :-) Well maybe it's participating to the issue. It's 0cf833ae (net: loopback: set default mtu to 64K). And I could reproduce it with 3.6 by setting loopback's MTU to 65536 by hand. The trick is that once the MTU has been set to this large a value, even when I set it back to 16kB the problem persists. Now I'm retrying your other patch to see if it brings the 10GE back to full speed. Willy