From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Rothwell Subject: Re: Large performance regression with 6in4 tunnel (sit) Date: Sun, 27 Nov 2016 14:23:40 +1100 Message-ID: <20161127142340.3a5c197e@canb.auug.org.au> References: <20161125120947.142c3af5@canb.auug.org.au> <20161125134520.68ca0969@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Eli Cooper , netdev@vger.kernel.org, Eric Dumazet To: Sven-Haegar Koch Return-path: Received: from ozlabs.org ([103.22.144.67]:43409 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752505AbcK0DXn (ORCPT ); Sat, 26 Nov 2016 22:23:43 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Hi Sven-Haegar, On Fri, 25 Nov 2016 05:06:53 +0100 (CET) Sven-Haegar Koch wrote: > > Somehow this problem description really reminds me of a report on > netdev a bit ago, which the following patch fixed: > > commit 9ee6c5dc816aa8256257f2cd4008a9291ec7e985 > Author: Lance Richardson > Date: Wed Nov 2 16:36:17 2016 -0400 > > ipv4: allow local fragmentation in ip_finish_output_gso() > > Some configurations (e.g. geneve interface with default > MTU of 1500 over an ethernet interface with 1500 MTU) result > in the transmission of packets that exceed the configured MTU. > While this should be considered to be a "bad" configuration, > it is still allowed and should not result in the sending > of packets that exceed the configured MTU. > > Could this be related? > > I suppose it would be difficult to test this patch on this machine? The kernel I am running on is based on 4.7.8, so the above patch doesn't come close to applying. Most fo what it is reverting was introduced in commit 359ebda25aa0 ("net/ipv4: Introduce IPSKB_FRAG_SEGS bit to inet_skb_parm.flags") in v4.8-rc1. -- Cheers, Stephen Rothwell