Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754920Ab1EGNix (ORCPT ); Sat, 7 May 2011 09:38:53 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:63530 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754416Ab1EGNit (ORCPT ); Sat, 7 May 2011 09:38:49 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=G15xj2HnUJ8ZD4vQfCpzspVqBn/u22Wwx8PgmoOJZuPBObnElkGMgogyaGtjQMpmVk 9f/Zqk7qozrRXY4U2KlU0iYTz425Dog9MT0lR5HNzteti6ukFAInC4+mnHA3zTGLmAbf khwwHy7TyCLcg7KsSNi2kvXbYLQwwBsdEQOoQ= Subject: Re: How to disable TCP checksum calculation? From: Eric Dumazet To: Alexander Clouter , "Wu, Xia" Cc: linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Sat, 07 May 2011 15:38:36 +0200 Message-ID: <1304775516.2821.1253.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1106 Lines: 34 Le samedi 07 mai 2011 à 08:28 +0100, Alexander Clouter a écrit : > Wu, Xia wrote: > > > > I'm studying TCP transporting efficiency. Now I want to disable TCP > > checksum calculation, but I cannot find the right way to disable it. > > Who can give me a help on how to disable TCP checksum on Linux? > > > Look at using TCP checksum offloading to see the effects: > > http://en.wikipedia.org/wiki/TCP_Offload_Engine > > ---- > berk:/home/alex# ethtool -k eth0 > Offload parameters for eth0: ... Not sure what We meant here. TCP standard requires checksums to be set, you cannot 'disable it'. Only possible thing in linux stack is to offload tcp checksum computation to network card, if hardware permits it. By the way, the loopback interface (lo) pretends to support this feature, so we dont compute tcp checksums for loopback. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/