From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hagen Paul Pfeifer Subject: Re: Raise initial congestion window size / speedup slow start? Date: Thu, 15 Jul 2010 00:13:01 +0200 Message-ID: <20100714221301.GI6682@nuttenaction> References: <4C3E0684.5060409@wildgooses.com> <4C3E1B54.40604@hp.com> <20100714203919.GD6682@nuttenaction> <20100714.145547.102555471.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: rick.jones2@hp.com, lists@wildgooses.com, davidsen@tmr.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: Content-Disposition: inline In-Reply-To: <20100714.145547.102555471.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org * David Miller | 2010-07-14 14:55:47 [-0700]: >Although section 3 of RFC 5681 is a great text, it does not say at all >that increasing the initial CWND would lead to fairness issues. Because it is only one side of the medal, probing conservative the available link capacity in conjunction with n simultaneous probing TCP/SCTP/DCCP instances is another. >To be honest, I think google's proposal holds a lot of weight. If >over time link sizes and speeds are increasing (they are) then nudging >the initial CWND every so often is a legitimate proposal. Were >someone to claim that utilization is lower than it could be because of >the currenttly specified initial CWND, I would have no problem >believing them. > >And I'm happy to make Linux use an increased value once it has >traction in the standardization community. Currently I know no working link capacity probing approach, without active network feedback, to conservatively probing the available link capacity with a high CWND. I am curious about any future trends. >But for all we know this side discussion about initial CWND settings >could have nothing to do with the issue being reported at the start of >this thread. :-) ;-) sure, but it is often wise to thwart these kind of discussions. It seems these CWND discussions turn up once every other month. ;-) Hagen