From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: Re: unstable 10GBE performance with recent kernels (> 3.0.X) Date: Mon, 18 Jun 2012 16:17:15 +0200 Message-ID: <4FDF386B.1040300@profihost.ag> References: <4FDEF34C.808@profihost.ag> <1340012706.7491.770.camel@edumazet-glaptop> <4FDEFD55.7010204@profihost.ag> <1340015143.7491.855.camel@edumazet-glaptop> <4FDF20B2.2010603@profihost.ag> <1340023876.7491.1153.camel@edumazet-glaptop> <4FDF2829.6050705@profihost.ag> <1340026144.7491.1231.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]:38298 "EHLO mail.profihost.ag" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751466Ab2FRORS (ORCPT ); Mon, 18 Jun 2012 10:17:18 -0400 In-Reply-To: <1340026144.7491.1231.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: Am 18.06.2012 15:29, schrieb Eric Dumazet: >> But with the latest long term stable vanilla kernel 3.0.34. >> >> # iperf -c HOST -t 60 >> >> works fine but with -d for using both directions i see around 9.8Gbit/s >> in one direction and only 300kb/s in the other direction. > > I would try using regular MTU. For 3.5.0-rc2 this works fine but decreases the speed from 9,9Gbit/s to 9,3Gbit/s. With mtu 9000 i get around 3-4Gbit/s (netstat -s attached below) With 3.0.34 MTU 9000 works fine with constant 9,9Gbit/s in both directions. > And post "netstat -s" results before/after your iperf. Tests with mtu 9000 and 3.5rc2: Pre: http://pastebin.com/raw.php?i=uBjsFKjs Post: http://pastebin.com/raw.php?i=TAK8JS6j Thanks again! Stefan