From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) (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 627FA3B29E for ; Sat, 4 Dec 2021 20:20:28 -0500 (EST) Received: by mail-io1-xd2a.google.com with SMTP id x10so8615756ioj.9 for ; Sat, 04 Dec 2021 17:20:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=LMoLLNqWwmPVWhbzjmq2kFbJfLXGvbN4jokydpODWD0=; b=cWWETczI11wjlYtAKRv9ig2C5Qe60U8BDrlbvSWCm/YTqY9rBLdnEtfbeppfS+B/Ha WOwpUX6KxKNs0CFwh29tG4QnVcC+zDBn0qVg4I3TdFKnKPr+tTuWKJqD9wqPgyWy9l1W zbTcJ1+grD1HbMp08jLJnVIjEd5L4oTFdyfBWbsirAuZ2DCLmFV3gAT+MGmDu/ly+Igi VX2KErmYThq9d03kR6pPV4Ya9vC1i/qf7unc1RDkYCE6jREfVE/keiDPW3PhhdnWD94n LcCZSvlGcPT3rBynbVBGlNwMP4XRC6AFbj+AwTrMcT8OWrn06/epWFG0/yJxL5wOYr7V vsWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=LMoLLNqWwmPVWhbzjmq2kFbJfLXGvbN4jokydpODWD0=; b=pqSdHFPUIsRS/3tREfHCZEpiemvbBlGpvjAadmeo2GsuN5xBoBGyoBzQrhhR26RCxg 1baJ0bFO3wwmLvXjJa0ibJjV4LKY/tfIHIYKGN4a8ZkQN3z+O2LpvULDRis3yQGR1esG KpuLbIS2DXB27mpoILOOz7bI6pnBWHZwwk6edpTUUrhT2g2GL5OpiQp1gbkj8PMSnf2y AlYTrquCyAlSsSXloSXYIDnuaiGRdAqKQ8rbnN9wugfTwVWnh87KwsTV1CJSlWIQRN+s ZwzgjYpMjOjgvbcbQK3X1MeOTpkqcAef2FQVvzUB54ie2eWqvuYfvml1+EIOQfBW9ji4 bUtg== X-Gm-Message-State: AOAM530nScfSPJC5KFMBOFGwhKjFDSl2rah1T67SWVgc/1Kp1Mpvcaea 8vYYBp6Ys+BvCwR3dlNBjpLasBECNaxpab34gnc= X-Google-Smtp-Source: ABdhPJyT1u6zyeqmT2OgrWWAU2YLtG/R1DyacjSzqMsJwgXVRyD1wlh0PCjUUCAYuxLpRIudSY7kmZGffpylxcfWNMg= X-Received: by 2002:a05:6602:2e81:: with SMTP id m1mr25313245iow.55.1638667227607; Sat, 04 Dec 2021 17:20:27 -0800 (PST) MIME-Version: 1.0 References: <0A6AB0B7-E010-42E3-BAEE-FCBFA5995117@gmail.com> <1638656999.711523536@apps.rackspace.com> In-Reply-To: <1638656999.711523536@apps.rackspace.com> From: Dave Taht Date: Sat, 4 Dec 2021 17:20:15 -0800 Message-ID: To: "David P. Reed" Cc: Jonathan Morton , jonathan.kua@deakin.edu.au, Cake List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] Understanding the Achieved Rate Multiplication Effect in FlowQueue-based AQM Bottleneck 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: Sun, 05 Dec 2021 01:20:28 -0000 On Sat, Dec 4, 2021 at 2:30 PM David P. Reed wrote: > > I just watched it. His assumption that "carrier networks can't solve the = problem because they can't control the hosts" is JUST WRONG! Step 1: Understand that microbursts exist: Win Step 2: Find a way to measure them at 100Gbit scale using the tofino switch and a viable data structure: Big win Step 3: Find a way to use that measurement in that switch to "do something":: ok, you object to this Step 4: Publish at conext: Normal Alternate step 3: Being able to leverage this tool to gain data about e2e behavior at these scales and make better applications is a huge win. From looking at the before sawtooth in what they did, they had a brick wall ecn configuration going against RFC3168 flows, and originally marked all packets over the threshold, leveraging RFC3168's non-response for more than one packet marked per RTT. The graph missing for me (and perhaps I should look again) was the effect of that, vs not marking at all, or marking more smartly, as they did. The second question for me has always been to what extent ECN of any form is being used in the datacenter today, in RFC3168 semi-compliant ways like this. It is, essentially, half on by default.... > > > The Internet solution is to require the flows' source hosts to regulate t= heir transmission based on dynamic feedback. >From where? tcp timestamps aren't granular enough. > > > > And this ignorance on his part is clearly his advisors' fault. > > > > The pattern here is: > > > > I make assumption that rules out better solutions. > > > > I then invent some complicated kludge "inside the network" and claim it s= olves the problem. > > > > Then I demand that networks put this kludge into the network. > > > > In other words, he takes an end-to-end problem (regulating source rates t= o achive low internal queue delay), and instead of implementing a solution = at the ends, he adds much more complexity inside the network. > > > > Violating the whole end-to-end argument. > > > > Or, simplifying the point: "we have smarts in the routers, that we aren't= using, so let's invent something to use them, even though there are better= solutions." > > > > Yuck! > > > > This is how we ended up with CISC computers, with operating systems that = shove huge amounts of function into protected mode with heavy use of shared= global variables protected by complicated locks. > > > > OK, this creates the need for complicated PhD theses where the coolness i= s how complicated the code was to get working. > > > > > > > > On Saturday, December 4, 2021 1:44pm, "Dave Taht" s= aid: > > > It was the conquest tool they referenced that really caught my eye > > > > https://www.youtube.com/watch?v=3DQ3FFzB0SUjc > > > > "ConQuest: Fine-Grained Queue Measurement in the Data Plane" > > > > On Fri, Dec 3, 2021 at 4:09 PM Jonathan Morton > > wrote: > > > > > > > On 4 Dec, 2021, at 12:27 am, Dave Taht > > wrote: > > > > > > > > > > https://jonathankua.github.io/preprints/jkua-ieeelcn2021_understanding_= ar_preprint-20jul2021.pdf > > > > > > > > I would love it if somehow the measured effects of chunklets agains= t > > cake's per-host/per flow fq was examined one day. > > > > > > I haven't actually measured it, but based on what the above paper say= s, I can > > make some firm predictions: > > > > > > 1: When competing against traffic to the same local host, the perform= ance > > effects they describe will be present. > > > > > > 2: When competing against traffic to a different local-network host, = the > > performance effects they describe will be attenuated or even entirely a= bsent. > > > > > > 3: They noted one or two cases of observable effects of hash collisio= ns in > > their tests with FQ-Codel. These will be greatly reduced in prevalence = with Cake, > > due to the set-associative hash function which specifically addresses t= hat > > phenomenon. > > > > > > - Jonathan Morton > > > > > > > > -- > > 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 > > _______________________________________________ > > Cake mailing list > > Cake@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/cake > > --=20 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