From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fan Du Subject: Re: [PATCHv2 net-next 0/4] Small fix for TCP PMTU Date: Fri, 27 Feb 2015 13:37:44 +0800 Message-ID: <54F002A8.307@gmail.com> References: <1423815405-32644-1-git-send-email-fan.du@intel.com> <1424922566-6787-1-git-send-email-fan.du@intel.com> <063D6719AE5E284EB5DD2968C1650D6D1CAEEABA@AcuExch.aculab.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: 'Fan Du' , "johnwheffner@gmail.com" , "edumazet@google.com" , "davem@davemloft.net" , "netdev@vger.kernel.org" To: David Laight Return-path: Received: from mail-pd0-f178.google.com ([209.85.192.178]:39366 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034AbbB0Fmg (ORCPT ); Fri, 27 Feb 2015 00:42:36 -0500 Received: by pdjy10 with SMTP id y10so18582342pdj.6 for ; Thu, 26 Feb 2015 21:42:36 -0800 (PST) In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CAEEABA@AcuExch.aculab.com> Sender: netdev-owner@vger.kernel.org List-ID: =E4=BA=8E 2015=E5=B9=B402=E6=9C=8826=E6=97=A5 21:40, David Laight =E5=86= =99=E9=81=93: > From: Fan Du >> >This patchset performs some small fix and enhancement >> >for current TCP PMTU as per RFC4821 with below changes: >> > >> >Patch1/4: Set probe mss base to 1024 Bytes per RFC4821 >> >Patch2/4: Do not double probe_size for each probing, >> > use a simple binary search to gain maximum performance. >> >Patch3/4: When it comes to blackhole detection, shrink current >> > mss for next probing. >> >Patch4/4: Create a probe timer to detect enlarged path MTU. > Isn't the most likely problem PPPoE blackholes? No. It's used to probe a optimal pmtu value for vxlan tunnel when ICMP mess= age is not available. Refer patch2/4 for test summary. > Where a reduction of the PMTU from 1500 to (IIRC) 1492 is > all that is required? > > Would seem appropriate to test that value reasonable quickly.