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 E9A073B2A3 for ; Mon, 27 Feb 2017 13:13:21 -0500 (EST) Received: from [172.17.3.29] ([134.76.241.253]) by mail.gmx.com (mrgmx001 [212.227.17.190]) with ESMTPSA (Nemesis) id 0LtZcC-1cGwnU1N6S-010s70; Mon, 27 Feb 2017 19:13:20 +0100 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 10.2 \(3259\)) From: Sebastian Moeller In-Reply-To: <9353cc42-220b-af1b-3105-19be52ed0627@gmail.com> Date: Mon, 27 Feb 2017 19:13:19 +0100 Cc: Jonathan Morton , cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <3F9B4D98-ED26-4B56-812E-783CBBF64AAF@gmx.de> References: <75e10bac-f982-655f-0ef6-483a36797479@gmail.com> <6EA3F28B-2A50-4BDB-A0D4-B94207BFF1A4@gmail.com> <3c0c8aab-2a9a-82a4-0828-d58c604d35dc@gmail.com> <028AA856-B11E-4025-B1BD-84BAC6768508@gmx.de> <9353cc42-220b-af1b-3105-19be52ed0627@gmail.com> To: Andy Furniss X-Mailer: Apple Mail (2.3259) X-Provags-ID: V03:K0:J+vz/ihh35eFOK6lgFuLeefemNO0E5hXpaz1qpK3VGMl1zsiktY lLD+m6cagb0pPMzvr008FNQ/U5a2uhYt4HqdzR8vG8d+ypqenEcJEZTW7VUimgNY3LjEn4Z nxGOkMB9WiSiUmpBvGXzos6BCZjGPBwMJz26VvTty+BERchUGvo4rUWtvc+o7TjXsHVuavW wGeEFe6u2txWEK0flt5gw== X-UI-Out-Filterresults: notjunk:1;V01:K0:0+vszPCmMTk=:bd0llT4DLux9toMVKtxclu /yGOWEM7WKPZKy5bTgNtnQWHdUcQZazFwAhl0LZzgmDEvkB3w9uF/ozXyndz/YYg6mMyg5SFd dpDcUpDIV5z8mUlrQ7NntSOWj0CE8aifwS3Ou1OpJIFwyJ1jEoFcwWYAfyIZuDKIwqyU0oZx4 Z7kkRF8xemzqLR+J820ocv77BLE9yjE1JVWNiO8YrG8T/svYlaETmqmzcQz2HRvhgEC2xC0zz AnjM88fV6MwKdkcwH91kwnw4e0ZoEOOc9RPwXuIdYa1GQCilWUAMhfFlhqUPRG4jWj8zIVEEZ maaokYo2nmp01+PThpddeTRkvTqcF9sbADrrkUY+IYZcJZ79PIaR4s5zEaQ0GSaJPAR82HHIT ooUXugt9k8Ojc6CldtxQcvKlO76xRlswsMfb3Wb+LQRlm6v4PghQ9QOe0O+tqrWdMAkYec8Al aUEHaWIH0A6KbJ66VhYi/IzOJNc+ITi1enic9/xcLNQIp6POeTy+T9V1JDBfIYE7mYVDZmxs4 Fiwg9cu2zpfT2Rb+bEflba4L0ztriJBHBEUySVgOOsMCz1p1SAndkPue8dmc7BBSTJ5MoMeqC dMpJ89I5CRBiaXyLXE8pS68srfp4Uf6jyMshrxxGmwTcJ7BzaolQa04lQVHnvOcLG3c8A/rnt RSvoJEygjL3mojh87PV6jK2yekkCVNCXCkqamt0gESfCnoB4uGAVnIvMk9xdDYlfVvPfKQgNc L+PIx4FOBVusuSibHgAxdwK8Fw9Nm+Mhm6ZBMWG7bFw5m7ggzAb1rZ5TibogqZknofWr8yJaL UlJ0ZGe Subject: Re: [Cake] 5ms target hurting tcp throughput tweakable? X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Feb 2017 18:13:22 -0000 Hi Andy, > On Feb 27, 2017, at 19:02, Andy Furniss wrote: >=20 > Sebastian Moeller wrote: >> Looking at tc-adv, I would recommend to use =E2=80=9Crtt 50=E2=80=9D = (maybe it is >> =E2=80=9Crtt 50ms=E2=80=9D) which allows to directly explicitly = request a new >> =E2=80=9Cinterval=E2=80=9D (which IIRC is corresponding to the time = you allow for >> the TCP control loop to react to cake=E2=80=99s ecn-marking/dropping) >> =E2=80=9Ctarget=E2=80=99 will be calculated as 5% of the explicit = interval, in >> accordance with the rationale in the codel RFC. >=20 > 50 is certainly better than 10, but still seems to hurt single a bit > even on a close server. Oopps, what I meant to convey is that there is the numeric = option =E2=80=9Crtt NNN=E2=80=9D that allows to select the exact = RTT/interval you believe to be valid. I picked 50 just because I wanted = to give a concrete example, not because I believe 50 to be correct for = your experiments... >=20 > On more distant servers maybe even more - I am getting results that = are > too variable to tell properly at the current time (of day). >=20 > = http://www.thinkbroadband.com/speedtest/results.html?id=3D1488216166262542= 155 >=20 > Almost OK, but with 100ms this test usually shows x1 and x6 the same. >=20 > = http://www.thinkbroadband.com/speedtest/results.html?id=3D1488218291872647= 755 Interesting. My mental image is that interval defines the time = you give both involved TCPs to get their act together before escalating = cake=E2=80=99s/codel=E2=80=99s signaling. The theory as far as I = understand it says that the RTT is the lower bound for the time = required, so I am not totally amazed that relaxing that interval a bit = increases bandwidth utilisation at a vert moderate latency cost (if = any). The art is to figure out how to pick the interval (and I believe = the codel paper showed, that at least for codel the exact number is not = so important but the ballpark/ order of magnitude should match). >=20 > Of course as we all know ingress shaping is a different beast anyway = and > would deserve its own thread. The cool thing is that ingress shaping with all its = =E2=80=9Capproximateness=E2=80=9D (is that a word) works as well as it = does ;) Best Regards