From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x32f.google.com (mail-wm1-x32f.google.com [IPv6:2a00:1450:4864:20::32f]) (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 289763CB38 for ; Sun, 21 Aug 2022 14:27:57 -0400 (EDT) Received: by mail-wm1-x32f.google.com with SMTP id d5so4555709wms.5 for ; Sun, 21 Aug 2022 11:27:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc; bh=R09bAs3uJ8nLHqrj59JnIwkfDjPkzS+M6Zn3Me6TjBo=; b=iLr17FzktvmLNMDDN7hCin/eKbLVB7oBUHK8jE2K+RDgtSnPwtZFaaM6Eyuyi4Tzlf sh/zr4fEZRZ5c2L/poq06e0ABBCWv50ErpQ0Kz9cxTgeKMqWiA8FZkLsMTUWL4t/ixmz oHWGKgn5dG6MLkdr9vpEZK8Tm9JeC3mZYGnbSJwC22QefWwJ8NtZuP7BK7SLr69oP5nk ru/NC07tEPptj7PXtzIhrc9Z8ws61nBK4YL869ozz16ECnxa5y7y+34vcVpB7dD4Do72 6HdkGtO5V0MdeI7GDhe/b9PJf5vho2Lr6vgtMcKKSiywMARd5NLtOGJAKh+N5jqe7C7L t2WA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc; bh=R09bAs3uJ8nLHqrj59JnIwkfDjPkzS+M6Zn3Me6TjBo=; b=wwSD8pTdM29XdL8eKfwJqkqxpRaTE8nymNmnQBCZJNIM96aDvDVxXvNKQ9DKBSVL95 eNB/ga8PzFqg5p1O2B2pJnSuUde/Gbo7IUeRADLfQaSRDMD280/hXEtzTsOnvYgIU/MP 4SvvY6xiEFnz+KUixJiYkc4Spjj+fLOyArcjLoa+hZVR7Vi5tm74g/eT3LgjnfcmC+qz /56p9zg2/Q1nIV7tPkXMgl8i0of3yY0NJtOlWG+Not/gy+NLqfKGMcVkAlQCegw13S8L Z+wOwtwHm6rOFtiuFMXm/ZYjPGmEM32ZR3TeMdzN+aUCSvsGoOXxVx30iTL8b9ZlGysM pYlA== X-Gm-Message-State: ACgBeo3OP8D9iLMZx9rFQYbqrTaAdcmhaIiwiOBcItwFY/faQTKwBpjg a/ceKwL6IBbOhdaM6VwxwKgekd1BLJkGj8tOp4Y= X-Google-Smtp-Source: AA6agR4CcBSodSc37d71c5LAOfyOazqYb7gBQojMe0U2EZFdsNnDTthAVqLapXWz58cFf680FVBq5AymUg4nh/OW0e8= X-Received: by 2002:a05:600c:3b9f:b0:3a6:53f:12fb with SMTP id n31-20020a05600c3b9f00b003a6053f12fbmr10466076wms.194.1661106475890; Sun, 21 Aug 2022 11:27:55 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Dave Taht Date: Sun, 21 Aug 2022 11:27:43 -0700 Message-ID: To: Qian Li Cc: bloat Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Bloat] less than best effort: TCP - flexis - A New Approach To Incipient Congestion Detection and Control 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: Sun, 21 Aug 2022 18:27:57 -0000 I have not had time to play with this much more, but it remains promising. Although you dismiss the ieas of not reducing the mss as not cost effective, I think for certain kinds of traffic it it worth pursuing. Also, based on some tests on a busy wifi network elsewhere, doing packet pacing on a per packet (rather than two packets at a time) seems interesting. What are you working on these days? On Fri, Apr 8, 2022 at 11:56 PM Qian Li wrote: > > Hello again, > > I have uploaded the source code to GitHub. You can find it here: > > https://github.com/tinalee77/FlexiS > > I have done some editing to the original code that was used to produce th= e results in the paper. First, I removed all debugging statements. Second, = I updated comments so that they are more readable. Third, I made variable n= ames consistent with the paper. And finally, I licensed it with Gnu GPL. > > Best regards, > Qian > > > > > > On Thu, Apr 7, 2022 at 10:35 PM Qian Li wrote: >> >> Hi Dave, >> >> I was just told that I am allowed to distribute the code freely. I will = upload it to GitHub and will send you the link as soon as I am done with it= . >> >> As for the AQM test, I set the QDisc to FQ-CoDel, CoDel, and CAKE, but n= one worked on CORE. In contrast, RED and PIE worked as expected. As far as = I know, the major difference between these two groups of AQMs is the time w= hen the packets are dropped. But I am not 100% sure it was the cause. I may= somehow test FlexiS or FlexiR (FlexiS adapted to the receiver side) on a t= estbed with various AQMs. But it will be toward the end of the adaptation I= guess :) >> >> Best regards, >> Qian >> >> On Thu, Apr 7, 2022 at 8:52 AM Dave Taht wrote: >>> >>> On Tue, Apr 5, 2022 at 8:44 AM Qian Li wrote: >>> > >>> > Dear Dave, >>> > >>> > Thank you for your interest in my work. >>> > >>> > I have read another paper authored by D. Rossi at el. presenting the = priority inversion problem of LEDBAT when it is used together with AQM. And= it has become one of the factors that motivated me to devise a new LBE CC = that can preserve low priority even when AQM is used. >>> >>> We'd given up hope circa 2014 as of the publication of the paper I >>> cited, and moved on. >>> >>> >However, I could not test FlexiS with CoDel on the CORE emulator proba= bly because CoDel drops packets at the dequeue time. >>> >>> I don't really understand that statement. >>> >>> > More tests should be done to verify that FlexiS does preserve low pri= ority in the presence of various AQM algorithms. >>> >>> Yes. until fairly recently I had had a testbed setup that allowed >>> testing of various tcps and aqm systems, but its been in storage since >>> covid. >>> >>> > I am now adapting FlexiS to the receiver side. The main motivation to= do so is that there might be HTTP/TCP proxies between the sender and the r= eceiver. A receiver side LBE CC and make the connection between the proxy a= nd the receiver LBE. In this work, I am going to tackle some open issues wi= th FlexiS. For example, I am going to test if trend analysis can be done ba= sed on one way delay so that the throughput is less affected by ack path co= ngestion. And I am going to evaluate various techniques to reduce rate belo= w 2 mss per RTT. This may include what you have suggested -- use small pack= ets and sub-packet window. I am also interested in using pacing to slow dow= n sending rate and maybe more alternative solutions. >>> >>> Cool! >>> >>> > >>> > I don't have a git tree for the source code mainly because I don't kn= ow if I am allowed to publish the code as open source. If you are intereste= d in the source code, I can ask the University of Oslo if I am allowed to d= istribute it freely? >>> >>> I would hope they would allow publication. The world is full of half >>> baked projects that if only someones new also stepped in, were >>> completed. An example of this is BBR which originally was about half >>> what it is today, until source was released among the right people. >>> >>> > >>> > Best regards, >>> > Qian >>> > >>> > >>> > >>> > On Sun, Apr 3, 2022 at 6:38 AM Dave Taht wrote: >>> >> >>> >> Dear Qian: >>> >> >>> >> Pretty promising paper. I liked that it tackled congestion on the ac= k >>> >> path, among other things. >>> >> >>> >> https://www.techrxiv.org/articles/preprint/TCP_FlexiS_A_New_Approach= _To_Incipient_Congestion_Detection_and_Control/19077161/1/files/33905018.pd= f >>> >> >>> >> I like also that you tackled, inter-rtt fairness, and, ledbat's >>> >> latecomer advantage problem, and in fig 9, the basic problem with >>> >> delay based LBE vs AQMs (in that ledbat degrades to reno)... [1] >>> >> >>> >> Towards your conclusion... >>> >> >>> >> I have always disagreed with the "don't reduce segment size" crowd, >>> >> btw. If you have a rate where you need to go below 2mss, it doesn't >>> >> hurt the network to reduce the size of the packet, and you can keep >>> >> the signal strength up by reducing that size and continuing to sampl= e >>> >> rtt, to respond quickly. >>> >> >>> >> Even if you are only passing a single byte of data, by lowering this >>> >> below everyone else's 2mss noise floor, you still eventually win, an= d >>> >> also you occupy space in packet fifos, reducing overall latency, as >>> >> bytes=3Dtime. IMHO. >>> >> >>> >> elsewhere, sub-packet windows are being experimented in bbrv2, I'm >>> >> told, but not in LBE. >>> >> >>> >> I'm also a big believer in packet pacing, and I think this is the >>> >> first paper I've seen that attempted LBE with it. Thx! >>> >> >>> >> Got a git tree? >>> >> >>> >> [1] do wish you'd had cited >>> >> https://perso.telecom-paristech.fr/drossi/paper/rossi14comnet-b.pdf >>> >> >>> >> -- >>> >> I tried to build a better future, a few times: >>> >> https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org >>> >> >>> >> Dave T=C3=A4ht CEO, TekLibre, LLC >>> >>> >>> >>> -- >>> I tried to build a better future, a few times: >>> https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org >>> >>> Dave T=C3=A4ht CEO, TekLibre, LLC --=20 FQ World Domination pending: https://blog.cerowrt.org/post/state_of_fq_code= l/ Dave T=C3=A4ht CEO, TekLibre, LLC