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 11:06:41 +0200 Message-ID: <4FE192A1.6000000@profihost.ag> References: <4FE0EA33.1000309@profihost.ag> <1340141493.4604.773.camel@edumazet-glaptop> <4FE17522.5050005@profihost.ag> <1340176940.4604.801.camel@edumazet-glaptop> <4FE1881B.7030800@profihost.ag> <1340181676.4604.838.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]:60374 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754709Ab2FTJGr (ORCPT ); Wed, 20 Jun 2012 05:06:47 -0400 In-Reply-To: <1340181676.4604.838.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: Am 20.06.2012 10:41, schrieb Eric Dumazet: > On Wed, 2012-06-20 at 10:21 +0200, Stefan Priebe - Profihost AG wrote: >> Am 20.06.2012 09:22, schrieb Eric Dumazet: > Yes, you already told that in subject line. > > single tcp flow ? I use iperf - i think it uses just a single tcp flow. But i'm not sure. > You seem to have a switch or something that drops packets in this case. > You could try to rate limit to 9Gb/s and see if it is better. Sadly i can't rate limit to 9Gbit/s on the switch. > Here, I roughly have same bandwidth with tcp_timestamps on or off, with > ixgbe cards and net-next kernels. Mhm strange. Do you have any vague idea what could cause this? Any wrong reordering of the packets without tcp_timestamps? Stefan