From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Graf Subject: Re: [RFC] skb align patch Date: Wed, 23 Sep 2009 01:47:48 -0400 Message-ID: <20090923054748.GA24045@bombadil.infradead.org> References: <4AB71980.4020208@gmail.com> <20090921213011.704e0594@nehalam> <4AB84295.3050509@gmail.com> <20090921.222940.258576265.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: eric.dumazet@gmail.com, shemminger@vyatta.com, jesse.brandeburg@gmail.com, hawk@diku.dk, netdev@vger.kernel.org To: David Miller Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:52567 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752032AbZIWFrs (ORCPT ); Wed, 23 Sep 2009 01:47:48 -0400 Content-Disposition: inline In-Reply-To: <20090921.222940.258576265.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Sep 21, 2009 at 10:29:40PM -0700, David Miller wrote: > The alignment in this patch is a real big deal for 64 byte forwarding > tests, where the entire packet is a whole PCI-E cacheline. But not > if it isn't aligned properly. As I pointed out to Herbert already, this alignment change may actually make things worse or even break things as long as compare_ether_header() used in __napi_gro_receive() expects the IP header to be aligned to 4 bytes. That can be fixed of course, just wanted to mention it.