From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: TCP rx window autotuning harmful at LAN context Date: Wed, 11 Mar 2009 16:01:49 +0100 Message-ID: <20090311150149.GG11935@one.firstfloor.org> References: <20090309200505.GA58375@bts.sk> <20090309.170927.130334650.davem@davemloft.net> <87bps8fkaw.fsf@basil.nowhere.org> <20090311.063058.236235660.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: andi@firstfloor.org, md@bts.sk, netdev@vger.kernel.org To: David Miller Return-path: Received: from one.firstfloor.org ([213.235.205.2]:58556 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750766AbZCKOmZ (ORCPT ); Wed, 11 Mar 2009 10:42:25 -0400 Content-Disposition: inline In-Reply-To: <20090311.063058.236235660.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Mar 11, 2009 at 06:30:58AM -0700, David Miller wrote: > From: Andi Kleen > Date: Wed, 11 Mar 2009 11:03:35 +0100 > > > Perhaps this points to the default buffer sizing heuristics to > > be too aggressive for >= 1GB? > > It's necessary Andi, you can't fill a connection on a trans- > continental connection without at least a 4MB receive buffer. Seems pretty arbitary to me. It's the value for a given bandwidth*latency product, but why not half or twice the bandwidth? I don't think that number is written in stone like you claim. Anyways it was just a test patch and it indeeds seems to address the problem at least partly. -Andi -- ak@linux.intel.com -- Speaking for myself only.