From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 5CABC3BA8E for ; Wed, 6 Jun 2018 04:16:00 -0400 (EDT) Received: from [10.11.12.41] ([134.76.241.253]) by mail.gmx.com (mrgmx002 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MUZG7-1fq9kz3QCh-00RG2g; Wed, 06 Jun 2018 10:15:50 +0200 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.4 \(3445.8.2\)) From: Sebastian Moeller In-Reply-To: <8360fcc1-002b-11f9-ba7c-7b054840acff@kit.edu> Date: Wed, 6 Jun 2018 10:15:49 +0200 Cc: Jonathan Foulkes , Jonathan Morton , bloat Content-Transfer-Encoding: quoted-printable Message-Id: References: <152717340941.28154.812883711295847116.malone@soybean.canonical.com> <4f67f9b3-05a1-8d15-0aee-dfe8ea730d7c@gmail.com> <73c25a21-0ace-b5ee-090e-d06fb3b8dc60@kit.edu> <3F65061F-4F05-4F3F-8A43-FFCC1D27F585@gmail.com> <61E48C91-AEF9-4FF4-9F83-45EC7148EC54@jonathanfoulkes.com> <9675C88A-FCC0-43EB-9C71-CBEFD67408CB@gmx.de> <8360fcc1-002b-11f9-ba7c-7b054840acff@kit.edu> To: "Bless, Roland (TM)" X-Mailer: Apple Mail (2.3445.8.2) X-Provags-ID: V03:K1:/YHh9EaZm881xj21MqVr3pYBjYHqUPn9fLIJ4r+GNHDm6sBnzV5 b4MRJFV8mlCJ4fpTZVJsQC9LcLJFp35O3j416uu9YaBK8R0fk2cqy4G82dzMRCrIJnDzfqg Be9YzIM9fbdMeby1SZvqjXaB0mT+9l7giqUimov2/jK4nRiDdAvgChHwrHEgU9GAZnNX4AD WksnlvehMuCcdrEChndsA== X-UI-Out-Filterresults: notjunk:1;V01:K0:I8CW1x+8Jw8=:qLlTaMTJ5lwJaYJY4keETg V9qay1VJd02sO83ej8Dw6+HlDhZfFYRJT0sd2zNvCjXGfA9FNEW4Ohakq4GNtqbZ9msgMDqjf N6RqrNrJY3GoxdPkBMmRzK+F1lXyYq93Ppxu59TV+ZlDIRbnPLXZubhN+KjclKuQX2cVE2Pqa XlhetCAQ0zeLt2p0lbD0btb61hAasipkPn59Fm66lrhC8Jv0SeHx2x47lHeIt2Nw7MYlPZR26 +gl0Z9qwWLUrmjBp1motIDS6ZoYMmJGs3ephLYgtTeeYakPGhWMQW1Barjcz3K4uhooewMbGn sJuO5PukvPOuGClTCiAM+hjNkSP1/j5J9L5hyYNxvT+xbvN+Wyga9VK5NJnFStZM1UDJiwRTp ZLvjz2yVwj06CCR9i7HzJMLC9KiV1X0Dtl5sTI0UUTUypYeP3p14GdNykgV1qTQCD/N66LBT5 VzmT4cWxXVVD2PQRzFIkTC9ifOmcizDmuSNJDcC+c+sy7Ju4nx3HOSZPmcKHzaQq+RWElVtIO epo/G713oOZXbVfm4aUnulrk+175hD9KfJVeB/s2IWIKoIlkwm1MXwcy/HMl8suBKWeMZcdYb tO50GO+nxCzMrFj7yNhxs5hq6lWUnxudHz2Kf5P5YB4s0Bu+hFfpRXykBpmn1IjPgpZGNBeWS KEoRbrUHr4K6zca3xzGIF6yFFipHvxZ2BAFR3eSS22Vx1gcEmI4KRLyZzqo8ahuSxlSGp0q03 Ubt+uXYu0UCB65u6oEVkYs72ADFdAIlnSLgZWxFgew/jhdrbRol752Oqd25ULp06SBgLlb7TU vo42FKD Subject: Re: [Bloat] [Bug 1436945] Re: devel: consider fq_codel as the default qdisc for networking X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 06 Jun 2018 08:16:00 -0000 > On Jun 6, 2018, at 09:44, Bless, Roland (TM) = wrote: >=20 > Hi, >=20 > Am 05.06.2018 um 20:34 schrieb Sebastian Moeller: >> The rationale for that decision still is valid, at low bandwidth = every opportunity to send a packet matters and every packet being = transferred will increase the queued packets delay by its serialization = delay. The question IMHO is more is 4 Mbps a reasonable threshold to = disable ECN or not. >=20 > ECN should be enabled irrespective of the current bottleneck = bandwidth. > I don't see any relationship between serialization delay with ECN. > Congestion control is about determining the right amount of inflight > data. ECN just provides an explicit congestion signal as feedback > and helps anyway. The main problem is IMHO that most routers have > no AQM in place in order to set the CE codepoint appropriately... Well, sending a packet incurs serialization delay for all queued = up packets, so not sending a packet reduces the delay for all packets = that are sent by exactly the serialization delay. If egress bandwidth is = precious (so when it is congested and low in comparison with the amount = of data that should be send) resorting to congestion signaling by = dropping seems okay to me, as that immeiately frees up a "TX-slot" for = another flow. Now, I do agree that for the affected flow itself ECN should be = better as signaling is going to be faster than waiting for 3 DupACKs. = But as always the proof is in the data, so I will refrain from making-up = more hypothesis and rather try to look into acquiring data. >=20 > Regards, > Roland >=20