From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: bad TSO performance in 2.6.9-rc2-BK Date: Wed, 22 Sep 2004 13:30:11 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <20040922133011.5885640b.davem@davemloft.net> References: <20040920063012.GL2825@krispykreme> <20040920203021.GD4242@wotan.suse.de> <20040921155835.18aee381.davem@davemloft.net> <20040922140000.GD27432@wotan.suse.de> <20040922111209.7887df53.davem@davemloft.net> <20040922195515.GA2619@wotan.suse.de> <4151DB6C.8050906@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: ak@suse.de, anton@samba.org, netdev@oss.sgi.com Return-path: To: Nivedita Singhvi In-Reply-To: <4151DB6C.8050906@us.ibm.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Wed, 22 Sep 2004 13:07:08 -0700 Nivedita Singhvi wrote: > Andi, was that with a netperf TCP stream test? I > would not have thought there would be no difference > prior to the changes DaveM made recently (now we > obey congestion window). We certainly got quite a bit > of a difference running SPECWeb etc, but that was on > the e1000s. A netperf single stream TCP test and something like SpecWEB are two different animals. The former rarely goes faster with TSO enabled simply because there is sufficient cpu and bus bandwidth to keep the card full. Whereas with something like SpecWEB the extra cpu and bus cycles are needed by other resources of the benchmark and thus performance goes up. I have no idea why people think TSO will make some single stream TCP test go faster, it doesn't buy you more bytes on the wire :-)