From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: Early SPECWeb99 results on 2.5.33 with TSO on e1000 Date: Thu, 05 Sep 2002 20:47:21 -0700 (PDT) Sender: netdev-bounce@oss.sgi.com Message-ID: <20020905.204721.49430679.davem@redhat.com> References: <200209051830.g85IUMdH096254@tempest.prismnet.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: tcw@tempest.prismnet.com, linux-kernel@vger.kernel.org, netdev@oss.sgi.com Return-path: To: hadi@cyberus.ca In-Reply-To: Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org From: jamal Date: Thu, 5 Sep 2002 16:59:47 -0400 (EDT) I would think shoving the data down the NIC and avoid the fragmentation shouldnt give you that much significant CPU savings. It's the DMA bandwidth saved, most of the specweb runs on x86 hardware is limited by the DMA throughput of the PCI host controller. In particular some controllers are limited to smaller DMA bursts to work around hardware bugs. Ie. the headers that don't need to go across the bus are the critical resource saved by TSO. I think I've said this a million times, perhaps the next person who tries to figure out where the gains come from can just reply with a pointer to a URL of this email I'm typing right now :-)