From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) (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 AA1663CB35 for ; Mon, 10 Aug 2020 11:34:28 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1597073659; bh=4CPLen5PGflln45Ou9co2V50OocmXCV1SkP8rLq/Gp4=; h=X-UI-Sender-Class:Date:In-Reply-To:References:Subject:To:CC:From; b=f54ZlFVX+KMtUHLG6Mo5PcqL6mRW7lZ/7nU5bL80T0+lk9Kzm733BWbzoXcMPV25U qCgvMFpuH5OmpUrw1LqyDVKXkAyUcYvlHoqFN2gS5znTl5L/gSjEySNRT1Re5z2AFA bdDRcTze0Mq+Kjf5xrrL6ban4lPb2LA82qy4Sc+8= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [10.56.182.216] ([80.187.114.216]) by mail.gmx.com (mrgmx104 [212.227.17.168]) with ESMTPSA (Nemesis) id 1MbRjt-1kgPRL3F9t-00bsbB; Mon, 10 Aug 2020 17:34:19 +0200 Date: Mon, 10 Aug 2020 17:34:09 +0200 User-Agent: K-9 Mail for Android In-Reply-To: References: <225a9c89-ac76-f21e-1450-5deeb3cd23eb@tomh.org> <04949cee-c4de-900c-e1b1-4b1f227933eb@rogers.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable To: bloat@lists.bufferbloat.net, Tom Henderson , Daniel Sterling , davecb@spamcop.net CC: Jonathan Morton , "dave.collier-brown@indexexchange.com" , bloat From: Sebastian Moeller Message-ID: <87878C8E-88D6-4218-A3D9-1CAE99CB1B59@gmx.de> X-Provags-ID: V03:K1:tqGuzz5LB1zhVS30ReNzBK4Q0Tw3f0xfPud/DtgQzKyIbW1vy6q syFAeYhXjIlgVlldK3ovsyvzfQ7xwP2Tkad0fADQyTI94JA9oU4pEqT0BP7H5OKfYL67Izh 447vrNiNMAvG/eIlb0L01bd7VQl+OZoJ+NkkyzQ9evcTwr0EttA6emZTZtkTU0FLbabNamp /dB2La+mUwi/6BeCnWIUA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:twODe8XbWzU=:JcE24rVL8VqP0XDgz9Y/r1 f7Zkak63LJaINFybdcAJlyPlf0ShdAa56g4/yCBuoKDQyGQ6Er0z2Q8mykDluiqUCrPErFT95 /v+M+/KhAh6yfrdUYyLIyxQDnmfv8pZzni5LHfBk0EsHrKb5dHL7DUBiD+a4ngtHmRJuzswMO 68Cje6FFEzlxdrPGTezTdKWIBRJ6yr+Yl4NfYm6INs/JAVctmqYf52TRi01JiAFZ4vwz3OwWX 36PLEhwvjHGBXvQVm8XaYKIRFEQ90JvrmZh4w1IG+2m+0fIx+exvLkFfXFH+b85CyUlxIvQ6B TxyAWcxaf/+YTTtMBYR/Z+wzVL3w+SBw0nGxB4x4hkRmg36xXdswOb6lxoiXljyKhl3zi3lgF gAjsb+du3K0TDBGAsCPR4MsjuEvh/BHaJvJpFrfRkrbims5TCTso2DYnAxQFO64K14OUQsTln IeFptpEQj3kiF2fSQRxVVJza+c7FFEk67HhqDzVfmXLkkgxi0CG3DZ+lBhkqdBbIoKrsT97WB u9XGEdRAiuz0a956f1agQnzDVyl1y73XqwFcWjXz33XY7fhosPBhzJBK8SAh7XSvrEZQPqxsQ vS3A+ta6uf19yXm+TZFGJgaeGrz2fd1gVgR1R0nBLRwUGv9GepbxK61Ra2Iu4Hs9wmA9N0XJS GSD/9LPWTF9CRJ64sQbyCiAJQMVTaVDRY4DQuEpFja/6Jc/4jv9LNL6UrMV8A2lUJEl49sGVM 2YhDhI1hPpN0EFgP4b3qoEbmZDYmgLU+NU+LgmG8KUTUJh+5a+uigwwUQbtddeUWS5U14wYuX tMM4rSnAPi7sbi69LHoDN+F5HE97oWornq8lUxMAcLn/Pm6NbWGqWitNrR6bzCtL4rz69cjtn hREYb5TfQ9TMCp037eowJSmrONcYDbEFnefep2WPxKPJe7KTzpF+CaPCqXN+9sSFitpo3enP9 nTminsw2hC0cJIDUuA7P7aO3jFarWlHN75pledEHzJ/06iv1fJkoj0IDLj2PUO01GnuoAHYEa iaSmSJkGmFbzJm55q0bgxnCvXvOfS5A+RcxoWAa2F2vrQkgb67dP7LJU3iJ+2Gx+XyY8eFBx1 b1m5B7cqz6YqzyXQyf9Yz32GMQ452IgPCgholQJRIQlAnBUhCNNjsDr3EPZXnOPWWYSzLi6K+ 0AQG0W2sOsmXu1ghQgTuBV7RiS2QV1Rtnv3XuIZH04kxH7NgP0UCXUaskdvjLNWBYUo8hCJsd fgGaxkrrANLv84xf4 Subject: Re: [Bloat] How about a topical LWN article on demonstrating the real-world goodness of CAKE? 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: Mon, 10 Aug 2020 15:34:29 -0000 Hi Tom, On 10 August 2020 17:08:49 CEST, Tom Henderson wrote: > >> so after much tweaking, I've got cake set to 40mbit down, 20mbit up, >> enforced by two cakes (one for each NIC)=2E that's fairly low -- > >Thanks for sharing this configuration experience, but it leads me back=20 >to a question I have about best current practice for deployment=2E=C2=A0 = Can=20 >CAKE/SQM handle dynamic Wi-Fi bandwidth due to Wi-Fi rate control=20 >selecting lower MCS to increase range, or does it rely on first getting > >the Wi-Fi deployed so that it has strong signal everywhere, and then=20 >finding a CAKE shaping rate that shaves off a few Mb/s from the highest > >capacity MCS so that the bottleneck always lands on the CAKE AQM?=C2=A0 I= t=20 >seems like the deployment that you shared with a separate router will=20 >require a predictable Wi-Fi rate, but I am wondering more about the >case=20 >in which CAKE is deployed on the AP=2E > >- Tom No, neither cake nor SQM can deal all too well with variable rate links, i= f we talk about link rate variations in the second to second range=2E But i= n OpenWrt both the ath9k and the ath10k WiFi drivers gained airtime fairnes= s modes, which do a pretty good job at keeping link sharing fair and WiFi b= ufferbloat low=2E=20 The issue here is not really that closely related to cake or sqm, but that= WiFi without AQL (airtime queueing limits, analog to wired Ethernet's byte= queue limits) does not give the required pushback for an upstream qdisc to= keep the WiFi queues at an acceptable/reasonable size and it also does not= really offer a reliable fast estimator of achievable rate, as far as I can= tell=2E The current best practice seems to be to instantiate cake/SQM on a reasona= bly fixed rate wan link and select WiFi cards/socs that offer decent airtim= e fairness=2E Works pretty well in practice=2E=2E=2E Best regards Sebastian > >_______________________________________________ >Bloat mailing list >Bloat@lists=2Ebufferbloat=2Enet >https://lists=2Ebufferbloat=2Enet/listinfo/bloat --=20 Sent from my Android device with K-9 Mail=2E Please excuse my brevity=2E