From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: 10GBE performance drop with net.ipv4.tcp_timestamps=0 Date: Wed, 20 Jun 2012 11:28:48 +0200 Message-ID: <1340184528.4604.849.camel@edumazet-glaptop> 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> <4FE192A1.6000000@profihost.ag> <4FE193FA.5030802@profihost.ag> <1340183854.4604.847.camel@edumazet-glaptop> <4FE196F4.3040900@profihost.ag> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Linux Netdev List To: Stefan Priebe - Profihost AG Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:37369 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751376Ab2FTJ2x (ORCPT ); Wed, 20 Jun 2012 05:28:53 -0400 Received: by bkcji2 with SMTP id ji2so5948977bkc.19 for ; Wed, 20 Jun 2012 02:28:52 -0700 (PDT) In-Reply-To: <4FE196F4.3040900@profihost.ag> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 2012-06-20 at 11:25 +0200, Stefan Priebe - Profihost AG wrote: > Am 20.06.2012 11:17, schrieb Eric Dumazet: > > On Wed, 2012-06-20 at 11:12 +0200, Stefan Priebe - Profihost AG wrote: > >> Am 20.06.2012 11:06, schrieb Stefan Priebe - Profihost AG: > >>>> 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. > > > If you exchange sender/receiver role between linux kernel versions, is > > it the same problem ? > I'm testing in both directions. So both are sending and receiving. > > I've now made tests with only one sending an the other receiving. > > When server B is the sender i get 4Gbit/s. When server A is the sender i > get full 9,9Gbit/s. > > Stefan To rule out bad hardware, could you try a 3.5-rc3 kernel on B ?