From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Mason Subject: Re: on the wire behaviour of TSO on/off is supposed to be the same yes? Date: Fri, 21 Jan 2005 13:58:53 -0600 Message-ID: <200501211358.53783.jdmason@us.ibm.com> References: <41F1516D.5010101@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com Return-path: To: Rick Jones In-Reply-To: <41F1516D.5010101@hp.com> Content-Disposition: inline Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org The benefit of TSO is not throughput, but CPU utilization. Throughput increase is usually a side effect because of better PCI DMA behavior (eg. large PCI transfers are better). Are you seeing a CPU utilization decrease? On Friday 21 January 2005 01:01 pm, Rick Jones wrote: > Is it indeed supposed to be the case that the on the wire behaviour of TCP with > TSO on/off is supposed to be the same? I'm seeing some cases (netperf > TCP_STREAM 2.6.10 sending to HP-UX 11.23) where the throughput differences are > >= 10 MB/s on an e1000 card (TSO being slower). I've got lots of netperf and > tcpdump but thought I'd ask first before dumping it onto the list. Actually, > i'll probably have to put it up on the net somewhere since it is O(200MB) in > total (although I have a smaller point example). > > sincerely, > > rick jones > > > -- Jon Mason jdmason@us.ibm.com