From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: Re: 10GBE performance drop with net.ipv4.tcp_timestamps=0 Date: Wed, 20 Jun 2012 09:00:50 +0200 Message-ID: <4FE17522.5050005@profihost.ag> References: <4FE0EA33.1000309@profihost.ag> <1340141493.4604.773.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Linux Netdev List To: Eric Dumazet Return-path: Received: from mail.profihost.ag ([85.158.179.208]:56018 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209Ab2FTHA4 (ORCPT ); Wed, 20 Jun 2012 03:00:56 -0400 In-Reply-To: <1340141493.4604.773.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: Am 19.06.2012 23:31, schrieb Eric Dumazet: > On Tue, 2012-06-19 at 23:08 +0200, Stefan Priebe wrote: >> i'm testing 10GBE speed with tweo servers. One with 3.5-rc3 nd thoe >> other one whith RHEL 6 (2.6.32 kernel). >> >> I noticed that setting >> net.ipv4.tcp_timestamps=0 >> >> descreased the performance from 9,7 Full Duplex to 3-4Gb/s. >> >> Is this bahviour fine? What should / could i tet? >> > > Really, you should provide more input than that, if you really want us > to help. *arg* forgot to add the pastebin links. Sorry. Speed degraded in this case from 9,88Gbit/s to 2,45Gbit/s. When i turn on timestamps it's perfect again. Server A has 3.5.0-rc3 and server B has an RHEL6 2.6.32 kernel. Before: http://pastebin.com/raw.php?i=1gVraWVc After: http://pastebin.com/raw.php?i=NSh8Y29s Thanks, Stefan