Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751975AbaBHQzn (ORCPT ); Sat, 8 Feb 2014 11:55:43 -0500 Received: from infra.glanzmann.de ([88.198.249.254]:60952 "EHLO infra.glanzmann.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751824AbaBHQzl (ORCPT ); Sat, 8 Feb 2014 11:55:41 -0500 Date: Sat, 8 Feb 2014 17:55:39 +0100 From: Thomas Glanzmann To: Eric Dumazet Cc: Eric Dumazet , "David S. Miller" , "Nicholas A. Bellinger" , target-devel , Linux Network Development , LKML Subject: Re: [PATCH] tcp: disable auto corking by default Message-ID: <20140208165539.GA22359@glanzmann.de> Mail-Followup-To: Eric Dumazet , Eric Dumazet , "David S. Miller" , "Nicholas A. Bellinger" , target-devel , Linux Network Development , LKML References: <20140206153640.GB4103@glanzmann.de> <1391727771.14985.41.camel@haakon3.risingtidesystems.com> <20140207051500.GB10916@glanzmann.de> <20140207075536.GB17815@glanzmann.de> <1391801597.1155.28.camel@haakon3.risingtidesystems.com> <20140207205142.GA8609@glanzmann.de> <20140208091828.GA16336@glanzmann.de> <20140208091944.GB16336@glanzmann.de> <1391871850.10160.103.camel@edumazet-glaptop2.roam.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1391871850.10160.103.camel@edumazet-glaptop2.roam.corp.google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Eric, > > Disable auto corking by default > We should let auto corking on during 3.14 development cycle so that we > can fix the bugs, and thing of some optimizations. I agree that leaving it enabled helps to find bugs, however I'm not happy with the round trip time degradation. > auto cork gives a strong incentive to applications to use > TCP_CORK/MSG_MORE to avoid overhead of sending multiple small > segments. I agree. But if it breaks the application many people won't be happy, for example I spend already 5 hours to track it down. > In the normal case, the extra delay is something like 10 us, so if an > application is really hit by this delay, its a strong sign it could be > improved, especially if auto corking is off. Yes, but 230 micro seconds for others. :-( > Lets wait the end of 3.14 dev cycle before considering this patch. I agree. Btw. I mixed up the pcaps for autocork on and off, so I moved the files that they know show what they should show. Cheers, Thomas -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/