From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x141.google.com (mail-il1-x141.google.com [IPv6:2607:f8b0:4864:20::141]) (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 779E63B29E for ; Wed, 22 Apr 2020 10:48:55 -0400 (EDT) Received: by mail-il1-x141.google.com with SMTP id q10so2163206ile.0 for ; Wed, 22 Apr 2020 07:48:55 -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:content-transfer-encoding; bh=TtBCB8njmpe9mzIch1+nmXVb9LlGaFDyR5dLKn18OU0=; b=OPWvym6b8h/Xk/xSdV3Tyyxz897qqPGJtXLEE7matoNpMX6ViIUyNTbgkx3ZD0FWf8 f+Tf7NH1wRMhyH9YyqA+DAQwpD/I3XsJRANiHdk4T7HBzLZPGSIlrUXt10EAnkxd0bh0 iI2C0VUniJmL8V7YATVWACUjUaYTJXEACK0so0spkMzL+xYPIkdXlizVFfroVZKAg/z9 1rJp/y0KW6HWaVJDDm+wEuDsnIMFaav3tVEEb4VD8vOCdWupNz7e0949VXrkgthjgkcc AWUZZBFstVyNpVduWOibdEwR4Cl4Y5KVNsGnGrAyUAaYOeXHqCI3unFyfdEapfXbH9cs NCFg== 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:content-transfer-encoding; bh=TtBCB8njmpe9mzIch1+nmXVb9LlGaFDyR5dLKn18OU0=; b=DWf8QqADy9IeLgFyV3h9G6MWSO5kklNzZYYJCIgIbIHo4+vohCFha3v1nOJjIo+33B Adw6X3buFN7QHM8Aq/zIepWZnIiCge3S4ugYjbS9P7hpWDwky8S8lc33xkucOgbP40wL paHCfvoNzVTtEJPfjeRaLzKF9dIjXZXMjHS3CWPWpzk55d1a23R0ud7ZYxk9bkQszrFl wVcED2+379VVoRWrqp8/zS34m8Jae4fj3zNs0S6eujbD7HNlo3+T4hjoLL+tBVv/OVJh gU8YV7WVjXcdg7IUjlX5ME4APMs7mwzHuKWzAF37htsF+CPbHQVv81LfyA2GGYhU2BL+ YOMw== X-Gm-Message-State: AGi0PuZJuWJeiXsDxIubtHW69WtmeZbP0ntltn1TnSZd4RiYOBnEktm3 jhtNjOiEu6vcyenI9sXRC6mGC0H4FlRoIeCMgzk= X-Google-Smtp-Source: APiQypIRV0sRhg12cCdWptQNoKbZUwixdBZnskNTj9hElAKfZdRdd7iuM+UEibl00aV39OropN+KswWT/mjsWkmjK64= X-Received: by 2002:a92:c7a9:: with SMTP id f9mr13013745ilk.0.1587566934777; Wed, 22 Apr 2020 07:48:54 -0700 (PDT) MIME-Version: 1.0 References: <75FEC2D9-BFC8-4FA2-A972-D11A823C5528@gmail.com> <603DFF79-D0C0-41BD-A2FB-E40B95A9CBB0@gmail.com> In-Reply-To: From: Dave Taht Date: Wed, 22 Apr 2020 07:48:43 -0700 Message-ID: To: Luca Muscariello Cc: Jonathan Morton , Cake List , Maxime Bizon Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] Advantages to tightly tuning latency 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: Wed, 22 Apr 2020 14:48:55 -0000 On Wed, Apr 22, 2020 at 2:04 AM Luca Muscariello wro= te: > > > > On Wed, Apr 22, 2020 at 12:44 AM Dave Taht wrote: >> >> On Tue, Apr 21, 2020 at 3:33 PM Jonathan Morton = wrote: >> > >> > > On 22 Apr, 2020, at 1:25 am, Thibaut wrote: >> > > >> > > My curiosity is piqued. Can you elaborate on this? What does free.fr= do? >> > >> > They're a large French ISP. They made their own CPE devices, and debl= oated both them and their network quite a while ago. In that sense, at lea= st, they're a model for others to follow - but few have. >> > >> > - Jonathan Morton >> >> they are one of the few ISPs that insisted on getting full source code >> to their DSL stack, and retained the chops to be able to modify it. I >> really admire their revolution v6 product. First introduced in 2010, >> it's been continuously updated, did ipv6 at the outset, got fq_codel >> when it first came out, and they update the kernel regularly. All >> kinds of great features on it, and ecn is enabled by default for those >> also (things like samba). over 3 million boxes now I hear.... >> >> with <1ms of delay in the dsl driver, they don't need to shape, they >> just run at line rate using three tiers of DRR that look a lot like >> cake. They shared their config with me, and before I lost heart for >> future internet drafts, I'd stuck it here: >> >> https://github.com/dtaht/bufferbloat-rfcs/blob/master/home_gateway_queue= _management/middle.mkd >> >> Occasionally they share some data with me. Sometimes I wish I lived in >> paris just so I could have good internet! (their fiber offering is >> reasonably buffered (not fq_codeled) and the wifi... maybe I can get >> them to talk about what they did) >> >> When free.fr shipped fq_codel 2 months after we finalized it, I >> figured the rest of the world was only months behind. How hard is it >> to add 50 lines of BQL oriented code to a DSL firmware? >> > > Free has been using SFQ since 2005 (if I remember well). > They announced the wide deployment of SFQ in the free.fr newsgroup. > Wi-Fi in the free.fr router was not as good though. They're working on it. :) > In Paris there is a lot of GPON now that is replacing DSL. But there is > a nation-wide effort funded by local administrations to get fiber > everywhere. There are small towns in the countryside with fiber. > Public money has made, and is making that possible. > There is still a little of Euro-DOCSIS, but frankly compared to fiber > it has no chance to survive. I am very, very happy for y'all. Fiber has always been the sanest thing. Is there a SPF+ gpon card yet I can plug into a convention open source router yet? > > I currently have 2Gbps/600Mbps access with orange.fr and free.fr has a su= bscription > at 10Gbps GPON. I won't tell you the price because you may feel depressed > compared to other countries where prices are much higher. I'd emigrate!!! > The challenge becomes to keep up with these link rates in software > as there is a lot of hardware offloading. At this point, I kind of buy the stanford sqrt(bdp) argument. All you really need for gigE+ fiber access to work well for most modern traffic is a fairly short fifo (say, 20ms). Any form of FQ would help but be hardly noticible. I think there needs to be work on the hop between the internet and the subscriber..= . Web traffic is dominated by RTT above 40mbit (presently). streaming video traffic - is no more than 20Mbit, and your occasional big download is a dozen big streams that would bounce off a short fifo well. gbit access to the home is (admittedly glorious, wonderful!) overkill for all present forms of traffic. I'm pretty sure if I had gig fiber I could come up with a way to use it up (exiting the cloud entirely comes to mind), but lacking new applications that demand that much bandwidth... I of course, would like to see lola ( https://lola.conts.it/ ) finally work, and videoconferencing and game stream with high rates and faster (even raw) encoding also has potential to reduce e2e latencies enormously at that layer. > > As soon as 802.11ax becomes the norm, software scheduling will become > a challenge. Do you mean in fiber or wireless? wireless is really problematic at ANY spe= ed. at gfiber, the buffering moved to the wifi, and there are other problems that really impact achievable bandwidth. When I was last in paris, I could "hear" 300+ access points from my apt, and could only get 100-200kbit per second out of the wireless n ap I had, unless I cheated and stuck my traffic in the VI queue. A friend of mine there, couldn't even get wifi across the room! Beacons ate into a lot of the available bandwidth. Since 5ghz (and soon 6ghz - is 6E a thing in france) is shorter range I'm hoping that's got better, but with 802.11ac and ax peeing on half the wifi spectrum by default, I imagine achievable rates in high density locations with many APs will be very low... and very jittery... and thus still require good ATF, fq, and aqm technologies. I have high hopes for OFDMA and DU but thus far haven't found an AP doing it. I'm not sure what to do about the beaconing problem except offer a free tradein to all my neighbors still emitting G style frames.... And in looking over some preliminary code for the mt76 ax chip, I worry about both bad design of the firmware, and insufficient resources on-chip to manage well. How is the 5G rollout going in france? I recently learned that much of japan is... wait for it... wimax. > > Luca --=20 Make Music, Not War Dave T=C3=A4ht CTO, TekLibre, LLC http://www.teklibre.com Tel: 1-831-435-0729