From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: net: more accurate skb truesize - regression on Microblaze Date: Tue, 10 Apr 2012 13:50:25 +0200 Message-ID: <1334058625.3126.101.camel@edumazet-glaptop> References: <4F83EB0E.4020104@monstr.eu> <1334046444.3126.12.camel@edumazet-glaptop> <1334046746.3126.13.camel@edumazet-glaptop> <4F83F166.4010208@monstr.eu> <1334057529.3126.90.camel@edumazet-glaptop> <4F841BB9.2030209@monstr.eu> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, John Williams , David Miller To: monstr@monstr.eu Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:43989 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753803Ab2DJLua (ORCPT ); Tue, 10 Apr 2012 07:50:30 -0400 Received: by bkcik5 with SMTP id ik5so4123710bkc.19 for ; Tue, 10 Apr 2012 04:50:29 -0700 (PDT) In-Reply-To: <4F841BB9.2030209@monstr.eu> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2012-04-10 at 13:38 +0200, Michal Simek wrote: > On 04/10/2012 01:32 PM, Eric Dumazet wrote: > > > > ll_temac allocates XTE_MAX_JUMBO_FRAME_SIZE frames, even for MTU=1500 ? > > yes. > > > > > Trying to allocate smaller packets would definitely help your tcp > > receiver performance and overall reliability (order-0 allocations > > instead of order-2) > > There is long history for ll_temac and axi emac drivers. and if you compare > them they are very similar with similar bugs. > In our distribution we are using older ll_temac driver where this is fixed. > Performance is much higher if you allocate buffers for actual mtu. > > Thanks, > Michal > > P.S.: Our plan is to start to use mainline drivers and fixing them to get > the same performance as we have with old one. It is one my todo list. Ah good, because this 9000+pad versus 1500+pad allocation is way more problematic than the (small) change on skb->truesize you bisected ;)