From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932509AbWFSO7w (ORCPT ); Mon, 19 Jun 2006 10:59:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932506AbWFSO7w (ORCPT ); Mon, 19 Jun 2006 10:59:52 -0400 Received: from mail.daysofwonder.com ([213.186.49.53]:42439 "EHLO mail.daysofwonder.com") by vger.kernel.org with ESMTP id S932509AbWFSO7w (ORCPT ); Mon, 19 Jun 2006 10:59:52 -0400 Subject: Re: 2.6.17: slow (as hell) tcp inbound transfers From: Brice Figureau To: Vincent Vanackere Cc: linux-kernel@vger.kernel.org In-Reply-To: <65258a580606190717t2cc5b28eg10fb4d64fe5ec1f3@mail.gmail.com> References: <1150725598.4985.27.camel@localhost.localdomain> <65258a580606190717t2cc5b28eg10fb4d64fe5ec1f3@mail.gmail.com> Content-Type: text/plain Date: Mon, 19 Jun 2006 16:59:47 +0200 Message-Id: <1150729187.4985.41.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Mon, 2006-06-19 at 16:17 +0200, Vincent Vanackere wrote: > On 6/19/06, Brice Figureau wrote: > > Now to the problem: I just finished the installation of a brand new > > 2.6.17 on a Dell PowerEdge 2850 which was running 2.6.16.19 really fine, > > and I'm encountering a strange issue. > > > > It seems that TCP inbound transfers (using either curl, or scp) are > > really slow except when issued on our gigabit LAN. > > Could you try the following to see if it cures your problem ? > > echo 0 > /proc/sys/net/ipv4/tcp_window_scaling Yes, that fixed it: # curl http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.17.tar.gz > /dev/null % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 49.3M 0 9856 0 0 2991 0 4:48:05 0:00:03 4:48:02 3680 # echo 0 > /proc/sys/net/ipv4/tcp_window_scaling # curl http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.17.tar.gz > /dev/null % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 1 49.3M 1 904k 0 0 86544 0 0:09:57 0:00:10 0:09:47 71173 Did something has changed between 2.6.16 and 2.6.17 regarding TCP window scaling ? I remember a discussion on lklm aroung 2.6.7 or so that finally ended as a bug in a firewall that wasn't handling TCP window scaling gracefully. That's certainly my case, I'll will have a look to that. Thanks for the help, -- Brice Figureau