From mboxrd@z Thu Jan 1 00:00:00 1970 From: Markus Trippelsdorf Subject: Re: "TCP: eth0: Driver has suspect GRO implementation, TCP performance may be compromised." message with "ethtool -K eth0 gro off" Date: Fri, 10 Mar 2017 13:22:08 +0100 Message-ID: <20170310122208.GA293@x4> References: <20170202123427.GA7212@x4> <1486042270.13103.26.camel@edumazet-glaptop3.roam.corp.google.com> <1486043964.13103.33.camel@edumazet-glaptop3.roam.corp.google.com> <20170203115457.GA5296@localhost.localdomain> <1486128246.21871.83.camel@edumazet-glaptop3.roam.corp.google.com> <20170203135355.GA3413@localhost.localdomain> <1486131366.21871.87.camel@edumazet-glaptop3.roam.corp.google.com> <20170203142828.GB3413@localhost.localdomain> <1486133253.21871.89.camel@edumazet-glaptop3.roam.corp.google.com> <20170206211226.GC3413@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Dumazet , netdev@vger.kernel.org To: Marcelo Ricardo Leitner Return-path: Received: from ud10.udmedia.de ([194.117.254.50]:33090 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936768AbdCJMWN (ORCPT ); Fri, 10 Mar 2017 07:22:13 -0500 Content-Disposition: inline In-Reply-To: <20170206211226.GC3413@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: On 2017.02.06 at 19:12 -0200, Marcelo Ricardo Leitner wrote: > On Fri, Feb 03, 2017 at 06:47:33AM -0800, Eric Dumazet wrote: > > On Fri, 2017-02-03 at 12:28 -0200, Marcelo Ricardo Leitner wrote: > > > > > Aren't you mixing the endpoints here? MSS is the largest amount of data > > > that the peer can receive in a single segment, and not how much it will > > > send. For the sending part, that depends on what the other peer > > > announced, and we can have 2 different MSS in a single connection, one > > > for each peer. > > > > > > If a peer later wants to send larger segments, it can, but it must > > > respect the mss advertised by the other peer during handshake. > > > > > > > I am not mixing endpoints, you are. > > > > If you need to be convinced, please grab : > > https://patchwork.ozlabs.org/patch/723028/ > > > > And just watch "ss -temoi ..." > > I still don't get it, but I also hit the warning on my laptop, using > iwlwifi. Not sure what I did in order to trigger it, it was by accident. I am running with your debugging patch applied since the beginning of February and was not able to reproduce the issue ever again. So I think your code is innocent and another bug (,that seems to be fixed since then) somehow caused the kernel to jump to the function. -- Markus