From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [PATCH] flow-dissector: Fix alignment issue in __skb_flow_get_ports Date: Fri, 10 Oct 2014 08:33:39 -0700 Message-ID: <1412955219.9362.13.camel@edumazet-glaptop2.roam.corp.google.com> References: <20141009.201248.1210454965155680255.davem@davemloft.net> <20141010035840.21428.359.stgit@ahduyck-workstation.home> <20141010.004708.1975127853551765914.davem@davemloft.net> <5437F072.5060502@redhat.com> <063D6719AE5E284EB5DD2968C1650D6D174C858B@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "'alexander.h.duyck@redhat.com'" , David Miller , "alexander.duyck@gmail.com" , "netdev@vger.kernel.org" To: David Laight Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:53459 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751347AbaJJPdl (ORCPT ); Fri, 10 Oct 2014 11:33:41 -0400 Received: by mail-pa0-f54.google.com with SMTP id ey11so1973563pad.13 for ; Fri, 10 Oct 2014 08:33:41 -0700 (PDT) In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D174C858B@AcuExch.aculab.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2014-10-10 at 14:57 +0000, David Laight wrote: > I think there is code to copy the IP and TCP headers to aligned memory > before they are parsed. There is no such thing. You are here on netdev list, please read the code before doing such claims. > ... > > > > The problem is the igb / ixgbe / fm10k hardware doesn't have a means of > > inserting padding from its side... > > Shoot the hardware engineers. > > You aren't going to get the performance you expect from a 10Ge card > unless the rx buffers are 'correctly' aligned. That is simply not true on current x86 cpus. They simply dont care at all. You cannot blame Intel for other arches.