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-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 388FA3B29E; Mon, 13 Mar 2023 16:01:00 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1678737655; i=moeller0@gmx.de; bh=WdOlot8F9P0nTHz66SK+V/XtQ+BO1b/8VpmzehLGLA4=; h=X-UI-Sender-Class:Subject:From:In-Reply-To:Date:Cc:References:To; b=RZ6A6gVMdKTNKhscbVU50jqQwjs34Nywo1SuKs77FIRm9wZ+T0ENNuuXHt/PyNO6d 1d2VOWSKjjoD0HQVOi/AG+XIqt6PTdBIdBOJiList34YoxfnGwq5s21+D6IEv+cNqW iTicRf03kKcY7J0iq8Dxr+A6FLUMRrosaAaTxqUe7QKXaMzd30/QQo5BIF4u4lI6aI KR/5t+Al5HAL/UOnKbN0s4b0bZ5bBUa2cMTNG8LqAX4yHV06CUzpvE8jGXif/iH63n zEMeZW7urd++rtHMaFwKyq3PLDJ/wFEXwqSHP6wobxroCZQBydEBrzk+B8NU3IBVEg ZudJ2k8r2l9hQ== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from smtpclient.apple ([95.112.228.62]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MY68d-1q3AUN3L5B-00YUbw; Mon, 13 Mar 2023 21:00:54 +0100 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.2\)) From: Sebastian Moeller In-Reply-To: <3f45d2a0b6e46d7b2775fb801e805f93@rjmcmahon.com> Date: Mon, 13 Mar 2023 21:00:54 +0100 Cc: dan , Jeremy Austin , Rpm , libreqos , Dave Taht via Starlink , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <70F71290-C6CB-4D19-8A88-F0F17C0BDDA2@gmx.de> References: <1672786712.106922180@apps.rackspace.com> <77CCAD19-07E0-4F9E-88C1-D207CF7BF376@cable.comcast.com> <83ffc0dad19e3343e49271889369cefc@rjmcmahon.com> <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> <13DE6E53-665F-4C20-BBE2-70E685421E9D@gmx.de> <22C819FA-DDD7-4B9B-8C09-8008D4273287@gmx.de> <5e7fac51071bdbb20837e72e7eedfc7c@rjmcmahon.com> <3f45d2a0b6e46d7b2775fb801e805f93@rjmcmahon.com> To: rjmcmahon X-Mailer: Apple Mail (2.3696.120.41.1.2) X-Provags-ID: V03:K1:6FNOsNJzd3ClAMG+hSPsiIKOe9r3uZTcOgfy4t1HpFD5m7uiwHB 1NcJ4meZiVz1u2vpRLRLckqmjhJlcT1VHzUnsJfOT0lBJ+kpWw2xPNcxTCIzttSeYzeiJ0m zsKMLekzd4sSokyvadZLn9yuG7FBGzHhHwp9CkQT4cXqmpNvZNFb0k3ntdQF5ZYh7Ytspgp kjuJLPBZZDMvy4LyPNCYQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:vE9n3IGsj+8=;26trLHOhJXSuW0EPta6GEQGhA6s vtx7UMNFx5uMn4uEsqQmFXu4uRRZO8NflwGV263oywZ4wOyx2nK5dMhHGalGfUuVvZu8/16nk iTZyoPqrD1vegwTHjNROKpEFFPztpfJ5101b+T/f1zD/yDdS7lyw0jk8pM7ZMQ5mA1KWR3YPa I/5sqBmr7juG81lWKsZCiGM6fEW6R34amu9Pdeel45ff8TYojOR3vqDilvtuk1B2Wa3FtCeQF 0Y5wzftFT1qKJeORfhawkds45Ri7dVZoPyYJsvmei3blAANyjcbKuBTxZiMhboHwr1d0+g7ys UaXWJcVhONN69QZq39laxDxLwsULlJd9QT5SQoBCNNGHI3NZtaRdcji8HNaR2a/9uqyRzn2FJ 4FsmQJappyR862sozm8ompD+GcbqFl8tMGqPRWjEXAw8X31pzV0+G9PSKUKF0ZCWfRHhhq3cd DhhlST73iX91pHW9LANnl0OFDfDv31e7qtvuIBXE/cuKv483Ax1tQwZY2v3+8ITqhV4Phe7+T qqsPCue1jt/S3k9MPdrwkvldcUx+Cg+Cv6K6q6FiOYdUEjp8qf39CllgQE9fDZai42/Lb2PvE /twJPMcvFOiwPkCvubqsv3J8gbMb/zqiDkIiVrglpzg3P38NxhuImmZEXKCwM8+CXghQvtZXY G5+rXNKCL9B3qnd7G2SHOZth5fpw7eWMOxeEvaUXmGxUHhTzePJVFUGPpRLndXQ+ADwQNHIG0 4+UPfQoqHT+BxVmHDTXCpnHzQEaytBUl/4DLYG6Hca6SKbPZ6Di/PfBmjUjivN8wE+0gNv8a3 3au2eDc31E31H7OFSfdYsC1Lnay5ozYyUlMKAfUODLmkajlb5XtHo6OUuYXHD5gqlkiHo8BbJ VUgCjOQQTjdtXM4i7zXPTjnXLWWPBOIaYOrtqWsnFngJLae69jL/STO3+bMkcP1XnJLgefOy+ jiDWyKvj1Ril8XX94iLRWkHTMvw= Subject: Re: [LibreQoS] [Starlink] [Rpm] [EXTERNAL] Re: Researchers Seeking Probe Volunteers in USA X-BeenThere: libreqos@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Many ISPs need the kinds of quality shaping cake can do List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Mar 2023 20:01:00 -0000 Hi Bob, > On Mar 13, 2023, at 20:32, rjmcmahon wrote: >=20 > On 2023-03-13 11:51, Sebastian Moeller wrote: >> Hi Bob, >>> On Mar 13, 2023, at 19:42, rjmcmahon = wrote: >>>> [SM] not really, given enough capacity, typical streaming = protocols >>>> will actually not hit the ceiling, at least the one's I look at = every >>>> now and then tend to stay well below actual capacity of the link. >>> I think DASH type protocol will hit link peaks. An example with = iperf 2's burst option a controlled WiFi test rig, server side first. >> [SM] I think that depends, each segment has only a finite length = and >> if this can delivered before slow start ends that burst might never >> hit the capacity? >> Regards >=20 > I believe most CDNs are setting the initial CWND so TCP can bypass = slow start. [SM] My take is not necessarily to bypass slow start, but to = kick it off with a higher starting point... which is the conservative = way to expedite slow-start. Real man actually increase the = multiplication factor instead, but there are few real men around = (luckily)... s I see both the desire to finish many smaller transfers = within the initial window (so the first RTT after the handshake IIUC). > Slow start seems an engineering flaw from the perspective of low = latency. [SM] Yes, exponential search, doubling every RTT is pretty = aggressive. > It's done for "fairness" whatever that means. [SM] It is doe because: a) TCP needs some capacity estimate b) preferably quickly c) in a way gentler than what was used before the congestion collapse. we are calling it slow-start not because it is slow in absolute = terms (it is pretty aggressive already) but IIUC because before slow start people where even more = aggressive (immediately sending at line rate?) I think we need immediate queue build-up feedback so each flow can look = at its own growth projection and the queue space shrinkage projection = and then determine where these two will meet. Essentially we need a = gently way of ending slow-start instead of the old chestnut, dump twice = as much data in flight into the network before we notice... it is this = part that is at odds with low latency. L4s, true to form with its = essential bit-banging of queue filling status over all flows in the LL = queue is essentially givvin too little information too late.=20 If I had a better proposal for a slow-start altenative I would make it, = but for me slow-start is similar to what Churchill is supposed to have = said about democracy "democracy is the worst form of government =E2=80=93 = except for all the others that have been tried."... >=20 > Bob