From mboxrd@z Thu Jan 1 00:00:00 1970 From: YOSHIFUJI Hideaki Subject: Re: [PATCH] ipv6: Limit mtu to 65572 bytes Date: Fri, 11 Apr 2014 12:26:53 +0900 Message-ID: <534760FD.9050306@linux-ipv6.org> References: <5345A2B3.7040602@gmail.com> <1397079665.16584.17.camel@edumazet-glaptop2.roam.corp.google.com> <20140409223546.GH27255@order.stressinduktion.org> <1397090170.16584.21.camel@edumazet-glaptop2.roam.corp.google.com> <20140410235459.GK27255@order.stressinduktion.org> <1397176824.16584.52.camel@edumazet-glaptop2.roam.corp.google.com> <1397180530.16584.69.camel@edumazet-glaptop2.roam.corp.google.com> <534753D4.6070600@linux-ipv6.org> <1397186427.16584.86.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Hannes Frederic Sowa , David Miller , Francois WELLENREITER , netdev@vger.kernel.org, YOSHIFUJI Hideaki To: Eric Dumazet Return-path: Received: from 94.43.138.210.xn.2iij.net ([210.138.43.94]:59451 "EHLO mail.st-paulia.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751938AbaDKD0z (ORCPT ); Thu, 10 Apr 2014 23:26:55 -0400 In-Reply-To: <1397186427.16584.86.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: Eric Dumazet wrote: > From: Eric Dumazet > > Francois reported that setting big mtu on loopback device could prevent > tcp sessions making progress. > > We do not support (yet ?) IPv6 Jumbograms and cook corrupted packets. > > We must limit the IPv6 MTU to (65535 + 40) bytes in theory. > > Tested: > > ifconfig lo mtu 70000 > netperf -H ::1 > > Before patch : Throughput : 0.05 Mbits > > After patch : Throughput : 35484 Mbits > > Reported-by: Francois WELLENREITER > Signed-off-by: Eric Dumazet Acked-by: YOSHIFUJI Hideaki --yoshfuji