From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: SACK scoreboard Date: Tue, 08 Jan 2008 22:41:44 -0800 (PST) Message-ID: <20080108.224144.234253941.davem@davemloft.net> References: <20080108.144456.173014334.davem@davemloft.net> <47844D1C.1060706@psc.edu> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: andi@firstfloor.org, ilpo.jarvinen@helsinki.fi, lachlan.andrew@gmail.com, netdev@vger.kernel.org, quetchen@caltech.edu To: jheffner@psc.edu Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:55794 "EHLO sunset.davemloft.net" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751306AbYAIGlp (ORCPT ); Wed, 9 Jan 2008 01:41:45 -0500 In-Reply-To: <47844D1C.1060706@psc.edu> Sender: netdev-owner@vger.kernel.org List-ID: From: John Heffner Date: Tue, 08 Jan 2008 23:27:08 -0500 > I also wonder how much of a problem this is (for now, with window sizes > of order 10000 packets. My understanding is that the biggest problems > arise from O(N^2) time for recovery because every ack was expensive. > Have current tests shown the final ack to be a major source of problems? Yes, several people have reported this. It's a real issue, and it's only going to get worse.