From owner-freebsd-net@FreeBSD.ORG Thu Oct 20 15:52:24 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2B43716A41F; Thu, 20 Oct 2005 15:52:24 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8753F43D62; Thu, 20 Oct 2005 15:52:23 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 13AC446B03; Thu, 20 Oct 2005 11:52:22 -0400 (EDT) Date: Thu, 20 Oct 2005 16:52:21 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Michael VInce In-Reply-To: <43579259.8060701@roq.com> Message-ID: <20051020165029.C28249@fledge.watson.org> References: <434FABCC.2060709@roq.com> <20051014205434.C66245@fledge.watson.org> <43564800.3010309@roq.com> <4356BBA1.3000103@wm-access.no> <43579259.8060701@roq.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-net@freebsd.org, stable@freebsd.org, =?ISO-8859-1?Q?Sten_Daniel_S=F8rsdal?= Subject: Re: Network performance 6.0 with netperf X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Oct 2005 15:52:24 -0000 On Thu, 20 Oct 2005, Michael VInce wrote: >> Are you by any chance using PCI NIC's? PCI Bus is limited to somewhere >> around 1 Gbit/s. So if you consider; Theoretical maxium = ( 1Gbps - >> pci_overhead ) >> > The 4 ethernet ports on the Dell server are all built-in so I am > assuming they are on the best bus available. At the performance levels you're interested in, it is worth spending a bit of time digging up the specs for the motherboard. You may find, for example, that you can achieve higher packet rates using specific combinations of interfaces on the box, as it is often the case that a single PCI bus will run to a pair of on-board chips. By forwarding on separate busses, you avoid contention, interrupt issues, etc. We have a number of test systems in our netperf test cluster where you can measure 20% or more differences on some tests depending on the combinations of interfaces used. Robert N M Watson