From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ot1-x342.google.com (mail-ot1-x342.google.com [IPv6:2607:f8b0:4864:20::342]) (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 D29743B29D; Sat, 4 Jul 2020 13:52:34 -0400 (EDT) Received: by mail-ot1-x342.google.com with SMTP id 95so18145891otw.10; Sat, 04 Jul 2020 10:52:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=CSMxriQ/IsQgxcv/52Eh4gWamuJ62uDIKUzC1tAUQ5U=; b=bO0zn67qBRTG/qsaPIFD61d4BnuX1L3kJjsluNDIZuYhq9+RQfJDbeVPV9jQIROoMQ xdLEij4i8okdWdMYe6bT2vTnCnM7fTAnvwPtyFB2ValyEsojyoR7I2mLPVjhPVT0hjV2 hGzo/ps7mJZOUAZVUes0AyqnFhq8j4IAwCrlEs094jSudzwl8IPWFODngWCqXNho1TQT dcadKW7GLFCXykQB00qYY54kPwtBpGzyM6VeIjdDY9a5f+5Gt0bH3yLsfmPYycwl6gV1 hTCKE5fqhhmNemenrQ4Z5U3JVeLZV7euFPIj6bLG7pTQkyR+zrIUpiQVaPcCxBPA5/nH KVzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=CSMxriQ/IsQgxcv/52Eh4gWamuJ62uDIKUzC1tAUQ5U=; b=AYfCaZ6x6aW6jyxpd3lWYsKWA9Lpo7HRuAfh1U9pwKRTHmcV4x1Geq9N+IsmAfgONd QL5d4I1HcO/dHi45D/zlr6Xv1FrsMH2f/gbO70oELSf+6JWdtCVRIbLBO3LcLv8BElzz eQ1YTZ31OxrVI99ssqSYhXX+10lrqyEtQbzAzgab697qKmndEPL+4mQRK3wIsRLS3Qth kgFspzIehLbWm4PLz4XTpio8frEZRBoiJ6JWMqTrW0NXob6wlYWp6NyIyQUdexHpTsdY 9iNYpYO0ltaRoW+6Bu1QoEs2gPZPQ3IshaAni8udApwxjfSATLK+4dwrD+wlCJDaOc85 tTDg== X-Gm-Message-State: AOAM531PWB/iVlx87q3j5GLocdoXjJk75q7koVWFWyRI9ieT4W27isGp sfE4lxHNmUsrLIpcisUtLz4aGtJrDt2/dbSI3+c= X-Google-Smtp-Source: ABdhPJx04zCVngSzoomEpRH5meODuZ9+CeSMynRyNU4RbCi+cOcQx6kXuIzum1Afp2DvjNVusI4JhaKoawSVHQ6+VuA= X-Received: by 2002:a9d:787:: with SMTP id 7mr23069235oto.333.1593885154006; Sat, 04 Jul 2020 10:52:34 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Daniel Sterling Date: Sat, 4 Jul 2020 13:52:16 -0400 Message-ID: To: Matt Mathis Cc: Dave Taht , Make-Wifi-fast , Carlo Augusto Grazia , jamshid@whatsapp.com, bloat Content-Type: text/plain; charset="UTF-8" X-Mailman-Approved-At: Mon, 06 Jul 2020 06:38:11 -0400 Subject: Re: [Make-wifi-fast] [Bloat] the future belongs to pacing X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Jul 2020 17:52:34 -0000 On Sat, Jul 4, 2020 at 1:29 PM Matt Mathis via Bloat wrote: "pacing is inevitable, because it saves large content providers money (more efficient use of the most expensive silicon in the data center, the switch buffer memory), however to use pacing we walk away from 30 years of experience with TCP self clock" at the risk of asking w/o doing any research, could someone explain this to a lay person or point to a doc talking about this more? What does BBR do that's different from other algorithms? Why does it break the clock? Before BBR, was the clock the only way TCP did CC? Also, I have UBNT "Amplifi" HD wifi units in my house. (HD units only; none of the "mesh" units. Just HD units connected either via wifi or wired.) Empirically, I've found that in order to reduce latency, I need to set cake to about 1/4 of the total possible wifi speed; otherwise if a large download comes down from my internet link, that flow causes latency. That is, if I'm using 5ghz at 20mhz channel width, I need to set cake's bandwidth argument to 40mbits to prevent video streams / downloads from impacting latency for any other stream. This is w/o any categorization at all; no packet marking based on port or anything else; cake set to "best effort". Anything higher and when a large amount of data comes thru, something (assumedly the buffer in the Amplifi HD units) causes 100s of milliseconds of latency. Can anyone speak to how BBR would react to this? My ISP is full gigabit; but cake is going to drop a lot of packets as it throttles that down to 40mbit before it sends the packets to the wifi AP. Thanks, Dan