From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: bad TSO performance in 2.6.9-rc2-BK Date: Wed, 22 Sep 2004 16:00:00 +0200 Sender: netdev-bounce@oss.sgi.com Message-ID: <20040922140000.GD27432@wotan.suse.de> References: <20040920063012.GL2825@krispykreme> <20040920203021.GD4242@wotan.suse.de> <20040921155835.18aee381.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andi Kleen , anton@samba.org, netdev@oss.sgi.com Return-path: To: "David S. Miller" Content-Disposition: inline In-Reply-To: <20040921155835.18aee381.davem@davemloft.net> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org On Tue, Sep 21, 2004 at 03:58:35PM -0700, David S. Miller wrote: > On Mon, 20 Sep 2004 22:30:21 +0200 > Andi Kleen wrote: > > > I see the same problem here, but it's even worse. I only get 150-200KB/s > > sending data with scp from a fast machine with e1000 with a gigabit link. > > netperf also gives only 250KB/s. > > So I re-enabled TSO support in the loopback driver to try and > reproduce this, but I can't. > > There has been a lot of churn in this area so please make sure you > are using the latest sources, all of my current TSO fixes are in > Linus's BK tree. I tried it with rc2bk8 again and the performance is much better (22MB/s) that what I got earlier with 2.6.8rc2, but still far below what 2.6.5 gets on the same hardware (68MB/s) Both tests with netperf over e1000. > And, take the patch below and do a loopback bandwidth test before > and after the patch is applied. Do things slow down when loopback > has TSO enabled just as it does for your gigabit interfaces? Without TSO ~755MB/s, with TSO ~600-620MB/s (results seem to be a bit variable). -Andi