From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: Re: [PATCH] tcp: make TCP quick ACK behavior modifiable Date: Mon, 23 Aug 2010 20:17:26 -0300 Message-ID: <20100823231726.GK2973@ghostprotocols.net> References: <20100823220129.GB2745@nuttenaction> <20100823.152330.184822588.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: chris.snook@gmail.com, hagen@jauu.net, eric.dumazet@gmail.com, netdev@vger.kernel.org, ilpo.jarvinen@helsinki.fi, shemminger@vyatta.com To: David Miller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752501Ab0HWXSF (ORCPT ); Mon, 23 Aug 2010 19:18:05 -0400 Content-Disposition: inline In-Reply-To: <20100823.152330.184822588.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: Em Mon, Aug 23, 2010 at 03:23:30PM -0700, David Miller escreveu: > From: Chris Snook > Date: Mon, 23 Aug 2010 18:19:45 -0400 > > > Just because we've allowed stupid TCP sysctls in the past does not > > mean we should continue to do so now. We recently made delayed ack a > > per-route tunable, so consistency would suggest we do the same here. > > Per-route tunables are more flexible, and as with the delayed ack > > patch, there are use cases where that granularity gives a clear > > advantage over a sysctl. For example, you may want to disable quick > > ack on a high-MTU path and enable it on a low-MTU path. > > > > If you need a hint for how to implement the per-route tunable, look > > for the delayed ack patch from early 2009. > > I completely agree with Chris that this should be a per-route rather > than a global sysctl tunable. My first impression was not so strong as to participate, if every tunable gets a knob, well, we'd be flying concordes in no time. But even with such reaction, I thought that if a tunable would be interesting to have would be a setsockopt one, that knowledgeable, performance/latency hungry actors would jump into as if they were really hungry. And yes, that knob I worked on got lost along the way, I guess I have to think again about it and submit. - Arnaldo