From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from iramx2.ira.uni-karlsruhe.de (iramx2.ira.uni-karlsruhe.de [141.3.10.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 34F523CB35 for ; Tue, 27 Nov 2018 07:48:21 -0500 (EST) Received: from i72vorta.tm.uni-karlsruhe.de ([141.3.71.26] helo=i72vorta.tm.kit.edu) by iramx2.ira.uni-karlsruhe.de with esmtp port 25 iface 141.3.10.81 id 1gRcmp-0006n0-Aj; Tue, 27 Nov 2018 13:48:19 +0100 Received: from [IPv6:::1] (ip6-localhost [IPv6:::1]) by i72vorta.tm.kit.edu (Postfix) with ESMTPS id 484A8420E0B; Tue, 27 Nov 2018 13:48:14 +0100 (CET) To: Michael Welzl , Luca Muscariello Cc: Jonathan Morton , bloat References: <65EAC6C1-4688-46B6-A575-A6C7F2C066C5@heistp.net> <86b16a95-e47d-896b-9d43-69c65c52afc7@kit.edu> From: "Bless, Roland (TM)" Openpgp: preference=signencrypt Autocrypt: addr=roland.bless@kit.edu; prefer-encrypt=mutual; keydata= xsFNBFi0OxABEACy2VohJ7VhSu/xPCt4/6qCrw4Pw2nSklWPfAYEk1QgrbiwgvLAP9WEhAIU w45cojBaDxytIGg8eaYeIKSmsXjHGbV/ZTfo8r11LX8yPYR0WHiMWZpl0SHUd/CZIkv2pChO 88vF/2FKN95HDcp24pwONF4VhxJoSFk6c0mDNf8Em/Glt9BcWX2AAvizTmpQDshaPje18WH3 4++KwPZDd/sJ/hHSXiPg1Gdhs/OG/C0CJguOAlqbgSVAe3qKOr1M4K5M+wVpsk373pXRfxd7 ZAmZ05iBTn+LfgVcz+AfaKKcsWri5CdTT+7JDL6QNQpox+b5FXZFSHnEIST+/qzfG7G2LqqY mml6TYY8XbaNyXZP0QKncfSpRx8uTRWReHUa1YbSuOxXYh6bXpcugD25mlC/Lu0g7tz4ijiK iIwq9+P2H1KfAAfYyYZh6nOoE6ET0TjOjUSa+mA8cqjPWX99kEEgf1Xo+P9fx9QLCLWIY7zc mSM+vjQKgdUFpMSCKcYEKOuwlPuOz8bVECafxaEtJJHjCOK8zowe2eC9OM+G+bmtAO3qYcYZ hQ/PV3sztt/PjgdtnFAYPFLc9189rHRxKsWSOb4xPkRw/YQAI9l15OlUEpsyOehxmAmTsesn tSViCz++PCdeXrQc1BCgl8nDytrxW+n5w1aaE8aL3hn8M0tonQARAQABzShSb2xhbmQgQmxl c3MgKFRNKSA8cm9sYW5kLmJsZXNzQGtpdC5lZHU+wsGABBMBCAAqAhsDBQkSzAMABQsJCAcC BhUICQoLAgQWAgMBAh4BAheABQJYtYdHAhkBAAoJEKON2tlkOJXuzWkP+wfjUnDNzRm4r34a AMWepcQziTgqf4I1crcL6VD44767HhyFsjcKH31E5G5gTDxbpsM4pmkghKeLrpPo30YK3qb7 E9ifIkpJTvMu0StSUmcXq0zPyHZ+HxHeMWkosljG3g/4YekCqgWwrB62T7NMYq0ATQe1MGCZ TAPwSPGCUZT3ioq50800FMI8okkGTXS3h2U922em7k8rv7E349uydv19YEcS7tI78pggMdap ASoP3QWB03tzPKwjqQqSevy64uKDEa0UgvAM3PRbJxOYZlX1c3q/CdWwpwgUiAhMtPWvavWW Tcw6Kkk6e0gw4oFlDQ+hZooLv5rlYR3egdV4DPZ1ugL51u0wQCQG9qKIMXslAdmKbRDkEcWG Oi2bWAdYyIHhhQF5LSuaaxC2P2vOYRHnE5yv5KTV3V7piFgPFjKDW+giCRd7VGfod6DY2b2y zwidCMve1Qsm8+NErH6U+hMpMLeCJDMu1OOvXYbFnTkqjeg5sKipUoSdgXsIo4kl+oArZlpK qComSTPhij7rMyeu/1iOwbNCjtiqgb55ZE7Ekd84mr9sbq4Jm/4QGnVI30q4U2vdGSeNbVjo d1nqjf3UNzP2ZC+H9xjsCFuKYbCX6Yy4SSuEcubtdmdBqm13pxua4ZqPSI0DQST2CHC7nxL1 AaRGRYYh5zo2vRg3ipkEzsFNBFi0OxABEAC2CJNp0/Ivkv4KOiXxitsMXZeK9fI0NU2JU1rW 04dMLF63JF8AFiJ6qeSL2mPHoMiL+fG5jlxy050xMdpMKxnhDVdMxwPtMiGxbByfvrXu18/M B7h+E1DHYVRdFFPaL2jiw+Bvn6wTT31MiuG9Wh0WAhoW8jY8IXxKQrUn7QUOKsWhzNlvVpOo SjMiW4WXksUA0EQVbmlskS/MnFOgCr8q/FqwC81KPy+VLHPB9K/B65uQdpaw78fjAgQVQqpx H7gUF1EYpdZWyojN+V8HtLJx+9yWAZjSFO593OF3/r0nDHEycuOjhefCrqr0DDgTYUNthOdU KO2CzT7MtweRtAf0n27zbwoYvkTviIbR+1lV1vNkxaUtZ6e1rtOxvonRM1O3ddFIzRp/Qufu HfPe0YqhEsrBIGW1aE/pZW8khNQlB6qt20snL9cFDrnB6+8kDG3e//OjK1ICQj9Y/yyrJVaX KfPbdHhLpsgh8TMDPoH+XXQlDJljMD0++/o7ckO3Sfa8Zsyh1WabyKQDYXDmDgi9lCoaQ7Lf uLUpoMvJV+EWo0jE4RW/wBGQbLJp5usy5i0fhBKuDwsKdLG3qOCf4depIcNuja6ZmZHRT+3R FFjvZ/dAhrCWpRTxZANlWlLZz6htToJulAZQJD6lcpVr7EVgDX/y4cNwKF79egWXPDPOvQAR AQABwsFlBBgBCAAPBQJYtDsQAhsMBQkSzAMAAAoJEKON2tlkOJXukMoP/jNeiglj8fenH2We 7SJuyBp8+5L3n8eNwfwY5C5G+etD0E6/lkt/Jj9UddTazxeB154rVFXRzmcN3+hGCOZgGAyV 1N7d8xM6dBqRtHmRMPu5fUxfSqrM9pmqAw2gmzAe0eztVvaM+x5x5xID2WZOiOq8dx9KOKrp Zorekjs3GEA3V1wlZ7Nksx/o8KZ04hLeKcR1r06zEDLN/yA+Fz8IPa0KqpuhrL010bQDgAhe 9o5TA0/cMJpxpLqHhX2As+5cQAhKDDsWJu3oBzZRkN7Hh/HTpWurmTQRRniLGSeiL0zdtilX fowyxGXH6QWi3MZYmpOq+etr7o4EGGbm2inxpVbM+NYmaJs+MAi/z5bsO/rABwdM5ysm8hwb CGt+1oEMORyMcUk/uRjclgTZM1NhGoXm1Un67+Rehu04i7DA6b8dd1H8AFgZSO2H4IKi+5yA Ldmo+ftCJS83Nf6Wi6hJnKG9aWQjKL+qmZqBEct/D2uRJGWAERU5+D0RwNV/i9lQFCYNjG9X Tew0BPYYnBtHFlz9rJTqGhDu4ubulSkbxAK3TIk8XzKdMvef3tV/7mJCmcaVbJ2YoNUtkdKJ goOigJTMBXMRu4Ibyq1Ei+d90lxhojKKlf9yguzpxk5KYFGUizp0dtvdNuXRBtYrwzykS6vB zTlLqHZ0pvGjNfTSvuuN Organization: Institute of Telematics, Karlsruhe Institute of Technology Message-ID: <4b75ff51-0bc2-9bd7-7759-0a4a2cbaedee@kit.edu> Date: Tue, 27 Nov 2018 13:48:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 8bit X-ATIS-AV: ClamAV (iramx2.ira.uni-karlsruhe.de) X-ATIS-Timestamp: iramx2.ira.uni-karlsruhe.de 1543322899.385070844 Subject: Re: [Bloat] when does the CoDel part of fq_codel help in the real world? 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: Tue, 27 Nov 2018 12:48:21 -0000 Hi Michael, Am 27.11.18 um 12:04 schrieb Michael Welzl: > I'm lost in this conversation: I thought it started with a statement saying that the queue length must be at least a BDP such that full utilization is attained because the queue never drains. I think it helps to distinguish between bottleneck buffer size (i.e., its capacity) and bottleneck buffer occupancy (i.e., queue length). My point was that full bottleneck utilization doesn't require any buffer occupancy at all. I think one should also distinguish precisely between different viewpoints: at the sender or at the bottleneck (aggregate of many flows from different sources with different RTTs). > To this, I'd want to add that, in addition to the links from Roland, the point of ABE is to address exactly that: https://tools.ietf.org/html/draft-ietf-tcpm-alternativebackoff-ecn-12 > (in the RFC Editor queue) Yep, because then the backoff is less drastic so the utilization is kept at a higher level even if the queue is much smaller than a BDP (that is concluded from the fact that when ECN is present an AQM will try to keep the queue much smaller). Our complementary approach was the AQM Steering approach that let's the AQM adapt. > But now I think you're discussing a BDP worth of data *in flight*, which is something else. Yes, maybe because I think it was confused, but it's anyhow related: having a BDP in flight will allow you fully utilize the link capacity, having BDP+x in flight will lead to having x queued up in the bottleneck buffer. So having 2BDP inflight will lead to 1 BDP on the wire and 1 BDP in the buffer. That's what loss based CC variants usually have and what BBRv1 set as limit. Regards, Roland