From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751387AbVI1Qbz (ORCPT ); Wed, 28 Sep 2005 12:31:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751398AbVI1Qby (ORCPT ); Wed, 28 Sep 2005 12:31:54 -0400 Received: from ns2.limegroup.com ([66.92.115.81]:24472 "EHLO ns2.limegroup.com") by vger.kernel.org with ESMTP id S1751392AbVI1Qbw (ORCPT ); Wed, 28 Sep 2005 12:31:52 -0400 Date: Wed, 28 Sep 2005 12:31:33 -0400 (EDT) From: Ion Badulescu X-X-Sender: ion@ionlinux.tower-research.com To: Alexey Kuznetsov cc: "David S. Miller" , linux-kernel@vger.kernel.org, linux-net@vger.kernel.org, netdev@vger.kernel.org Subject: Re: Possible BUG in IPv4 TCP window handling, all recent 2.4.x/2.6.x kernels In-Reply-To: <20050902183656.GA16537@yakov.inr.ac.ru> Message-ID: References: <20050901.154300.118239765.davem@davemloft.net> <20050902183656.GA16537@yakov.inr.ac.ru> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Alexey, On Fri, 2 Sep 2005, Alexey Kuznetsov wrote: > Anyway, ignoring this puzzle, the following patch for 2.4 should help. > > > --- net/ipv4/tcp_input.c.orig 2003-02-20 20:38:39.000000000 +0300 > +++ net/ipv4/tcp_input.c 2005-09-02 22:28:00.845952888 +0400 > @@ -343,8 +343,6 @@ > app_win -= tp->ack.rcv_mss; > app_win = max(app_win, 2U*tp->advmss); > > - if (!ofo_win) > - tp->window_clamp = min(tp->window_clamp, app_win); > tp->rcv_ssthresh = min(tp->window_clamp, 2U*tp->advmss); > } > } I'm very happy to report that the above patch, applied to 2.6.12.6, seems to have cured the TCP window problem we were experiencing. I've been testing it extensively over the last 4 weeks, and I have yet to see any repeats of the previous behavior. The TCP window now usually settles to around 4k (unscaled, 16k scaled), which is smallish but good enough for our purposes. Thanks, -Ion