From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: Re: Data corruption issue with splice() on 2.6.27.10 Date: Tue, 6 Jan 2009 08:54:42 +0000 Message-ID: <20090106085442.GA9513@ff.dom.local> References: <20081224152841.GB13113@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jens Axboe , linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: Willy Tarreau Return-path: Received: from mail-ew0-f17.google.com ([209.85.219.17]:33311 "EHLO mail-ew0-f17.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbZAFIyu (ORCPT ); Tue, 6 Jan 2009 03:54:50 -0500 Content-Disposition: inline In-Reply-To: <20081224152841.GB13113@1wt.eu> Sender: netdev-owner@vger.kernel.org List-ID: On 24-12-2008 16:28, Willy Tarreau wrote: > Hi Jens, > > I'm facing a data corruption problem with splice() between two > non-blocking TCP sockets on 2.6.27.10. I could finally write a > simpler proof of concept, and capture a snapshot of the issue > with the associated strace result. ... > I found an analysis [1] for a potential corruption problem between two > sockets, but I noticed there were no responses and I did not fully > understand the report anyway. > > What can I do to help debug the problem ? I'm really willing to help > getting this fixed, and I also have at least one user who definitely > wants splice() to work because the recv/send model currently limits > haproxy to 3 Gbps on his machines, while I have no problem reaching > 10 Gbps with splice(). ... > ---- > [1] http://lkml.org/lkml/2008/2/26/210 Great story! Alas I don't understand this fully either, but it seems Changli Gao was concerned with sendpage sending this "as pages", so when NETIF_F_SG flag is available. Did you try this without SG btw? Thanks, Jarek P.