From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: RFC: Nagle latency tuning Date: Tue, 09 Sep 2008 00:55:57 +0200 Message-ID: <87ljy2tfgi.fsf@basil.nowhere.org> References: <48C59F75.6030504@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Netdev To: Christopher Snook Return-path: Received: from one.firstfloor.org ([213.235.205.2]:56387 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751949AbYIHWz5 (ORCPT ); Mon, 8 Sep 2008 18:55:57 -0400 In-Reply-To: <48C59F75.6030504@redhat.com> (Christopher Snook's message of "Mon, 08 Sep 2008 17:56:05 -0400") Sender: netdev-owner@vger.kernel.org List-ID: Christopher Snook writes: > > I'm afraid I don't know the TCP stack intimately enough to understand > what side effects this might have. Can someone more familiar with the > nagle implementations please enlighten me on how this could be done, > or why it shouldn't be? The nagle delay you're seeing is really the delayed ack delay which is variable on Linux (unlike a lot of other stacks). Unfortunately due to the way delayed ack works on other stacks (especially traditional BSD with its fixed 200ms delay) there are nasty interactions with that. Making it too short could lead to a lot more packets even in non nagle situations. Ok in theory you could split the two, but that would likely have other issues and also make nagle be a lot less useful. -Andi -- ak@linux.intel.com