From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Krogh Subject: Re: NIU - Sun Neptune 10g - Transmit timed out reset (2.6.24) Date: Thu, 22 May 2008 18:32:07 +0200 Message-ID: <4835A007.7020601@krogh.cc> References: <4824CBA1.8040703@sun.com> <4824CCF0.5050302@krogh.cc> <4824D1E1.10007@sun.com> <20080509.154538.28321777.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Matheos.Worku@Sun.COM, yhlu.kernel@gmail.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: Received: from 2605ds1-ynoe.1.fullrate.dk ([90.184.12.24]:55366 "EHLO shrek.krogh.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753846AbYEVQcT (ORCPT ); Thu, 22 May 2008 12:32:19 -0400 In-Reply-To: <20080509.154538.28321777.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: David Miller wrote: > From: Matheos Worku > Date: Fri, 09 May 2008 15:36:17 -0700 > >> I have observed TX throughput degradation (and increased CPU >> utilization) occurs with increased # of connections, when CPU count > 4 >> CPUs. I don't think it is related to the driver (or HW). > > All transmits through a device are fully serialized currently, > it's a known problem and something we plan to fix. I google'd up this one: http://vger.kernel.org/~davem/davem_tokyo08.pdf (slide 23+). Does this mean that I can expect every 10G card to have this limitation under Linux? Or are some known to be better than others? (I can probably justify paying for another 10G card if I can expect to gain the last 400MB/s). Since I cannot push more than ~600MB/s through the NIC before a single cpu is bottlenecked, it seem most likely to be this TX throughput thing I hit. Thanks Jesper -- Jesper