From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH net-next 11/15]bnx2x: Add TPA, Broadcoms HW LRO Date: Tue, 17 Jun 2008 16:17:06 +0100 Message-ID: <20080617151704.GK5350@solarflare.com> References: <1213714166.5817.181.camel@lb-tlvb-eliezer> <20080617150539.GJ5350@solarflare.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Miller , netdev , Michael Chan , Vladislav Zolotarov To: Eilon Greenstein Return-path: Received: from smarthost03.mail.mbr-roch.zen.net.uk ([212.23.3.142]:43891 "EHLO smarthost03.mail.zen.net.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755739AbYFQPRL (ORCPT ); Tue, 17 Jun 2008 11:17:11 -0400 Content-Disposition: inline In-Reply-To: <20080617150539.GJ5350@solarflare.com> Sender: netdev-owner@vger.kernel.org List-ID: Ben Hutchings wrote: > Eilon Greenstein wrote: > > The TPA stands for Transparent Packet Aggregation. When enabled, the FW > > aggregate in-order TCP packets according to the 4-tuple match and sends > > 1 big packet to the driver. This packet is stored on an SGL in which > > each SGE is 1 page. The FW also implements a timeout algorithm and it > > honors all TCP flag, including the push flag as a trigger to halt > > aggregation. > [...] > > LRO is not compatible with forwarding and will currently trigger a BUG() or > WARN() if used on packets that are then forwarded. Actually, since this implementation doesn't set gso_size in LRO'd skbs, it will confuse TCP in interesting ways instead. You need to set gso_size to the largest segment size seen in the packets that were aggregated. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job.