From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: Stable regression with 'tcp: allow splice() to build full TSO packets' Date: Thu, 17 May 2012 19:38:25 +0100 Message-ID: <1337279905.2496.23.camel@bwh-desktop.uk.solarflarecom.com> References: <20120517121800.GA18052@1wt.eu> <20120517150157.GA19274@1wt.eu> <1337269380.3403.10.camel@edumazet-glaptop> <20120517155621.GK14498@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , To: Willy Tarreau Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:30687 "EHLO ocex02.SolarFlarecom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1762310Ab2EQSic (ORCPT ); Thu, 17 May 2012 14:38:32 -0400 In-Reply-To: <20120517155621.GK14498@1wt.eu> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2012-05-17 at 17:56 +0200, Willy Tarreau wrote: [...] > The NIC does not support TSO but I've seen an alternate driver for this > NIC which pretends to do TSO and in fact builds header frags so that the > NIC is able to send all frames at once. I think it's already what GSO is > doing but I'm wondering whether it would be possible to get more speed > by doing this than by relying on GSO to (possibly) split the frags earlier. [...] Yes, GSO has some overhead for skb allocation and additional function calls that you can avoid by doing 'TSO' in the driver. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.