From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Re: [net] e1000: Small packets may get corrupted during padding by HW Date: Mon, 17 Sep 2012 20:27:01 -0700 Message-ID: <5057EA05.8020005@gmail.com> References: <50578DE4.7080806@intel.com> <1347915723.26523.179.camel@edumazet-glaptop> <5057E3F2.5090504@gmail.com> <20120917.230300.653531213751776624.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: eric.dumazet@gmail.com, alexander.h.duyck@intel.com, tushar.n.dave@intel.com, john.r.fastabend@intel.com, mirqus@gmail.com, jeffrey.t.kirsher@intel.com, netdev@vger.kernel.org, gospo@redhat.com, sassmann@redhat.com To: David Miller Return-path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:45912 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932283Ab2IRD1K (ORCPT ); Mon, 17 Sep 2012 23:27:10 -0400 Received: by obbuo13 with SMTP id uo13so9896988obb.19 for ; Mon, 17 Sep 2012 20:27:09 -0700 (PDT) In-Reply-To: <20120917.230300.653531213751776624.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 9/17/2012 8:03 PM, David Miller wrote: > From: Alexander Duyck > Date: Mon, 17 Sep 2012 20:01:06 -0700 > >> Since MAX_TCP_HEADER starts at 160 the likelihood of it not getting >> at least 16 bytes of padding is pretty low. > I know it's not on many people's radar, but with SLOB it will happen > a lot probably. That is true. I hadn't thought about anything other than SLAB/SLUB. It also just occurred to me that there might be some benefit in cache aligning the max header size. It seems like doing something like that should reduce the overall memory footprint and would probably improve performance. Thanks, Alex