From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Jones Subject: Re: [PATCH net-next] tcp: auto corking Date: Fri, 06 Dec 2013 13:34:28 -0800 Message-ID: <52A242E4.2090304@hp.com> References: <1386311765.30495.246.camel@edumazet-glaptop2.roam.corp.google.com> <52A1F603.2030208@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev To: David Laight , Eric Dumazet , David Miller Return-path: Received: from g6t0187.atlanta.hp.com ([15.193.32.64]:39437 "EHLO g6t0187.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752511Ab3LFVeb (ORCPT ); Fri, 6 Dec 2013 16:34:31 -0500 In-Reply-To: <52A1F603.2030208@hp.com> Sender: netdev-owner@vger.kernel.org List-ID: On 12/06/2013 08:06 AM, Rick Jones wrote: > I was wondering why Nagle didn't catch these things as well. The > netperf command line Eric provided though didn't include the > test-specific -D option that would have disabled Nagle. At least not > unless the "super_netperf" wrapper was adding it. > > So, why doesn't Nagle catch what is presumably a sub-MSS send while > there is data outstanding on the connection? Because this is operating "above" (as it were) Nagle and is looking only to try to get the successive small sends into a smaller number of skbs yes? So that when there is either no data outstanding, or an MSS's worth of data it will be in a small(ish) number of skbs not a long chain of them. rick jones