From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x244.google.com (mail-oi0-x244.google.com [IPv6:2607:f8b0:4003:c06::244]) (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 A047A3B260; Mon, 2 May 2016 10:18:34 -0400 (EDT) Received: by mail-oi0-x244.google.com with SMTP id i2so27293554oib.3; Mon, 02 May 2016 07:18:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-transfer-encoding; bh=dKE6g4HhOf6+8afFsJG8dZBxCDMJuNmnGp4BWTOY+Uw=; b=qiBnoZt16RmXFQJHFytRm5jduTjHt1y68uG7MzG84S/i9dA+Lr2yiaCr9/NIiVgMqv hDhI7Q77vpWpJ4/Lhgv9wlcjrxFRUgXTjzHjR77MpJcpzg5e4U1ejk27UFZCpIGwZsKS 6A7+NIxXixjLkPYm5VQkS5HqEC7QavHQ1sAmn5ofvt71JJEoSZKCo/rjmV2oGHUgwVVA He8W6CVQXB3c86BSwu+k0P/axsbjtmZpvINfDRoLLs6NRrhfQi4xY24qGfu7o+GkSQI5 HBoo2eFnCTV3aQqi8SfrFWfZUZ+8OqpWPm8/v8+2n4wu54Ojgh6iIbvqrbnBfGgbmM4b WyIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-transfer-encoding; bh=dKE6g4HhOf6+8afFsJG8dZBxCDMJuNmnGp4BWTOY+Uw=; b=a7MmQuoM4iC8mMY4yrxH1WHlCjlqajn0VALPzW/Y/p/cleH4WCEv4OoXML3XVG+Vb3 sc2I6/8anF8C+CO4lJ5yNa0StUYpARXKNWN7k12xGAdc72PHk4gMW1Rl2d5srNZzfLIP rMH8A+vaC9UpVxppmh4o93yoqVyI1F1TdikHs2nR566kY1wXwdpocrOngB0yp8P9ggBO awhoOnr5S/r0Sa6t7QJ3NzMkHGurYLklLNNRmMdpMw8FpJv/Vpx+4z5ePIZzx8OET6F0 k9Pmr9ZzH6hrR4F0mjqr3OFU2gaIsQSAPm2Hdhzlq6CUSGiweZuHlxlwA1OINU26I2rt rxzA== X-Gm-Message-State: AOPr4FXDZEZaLQZtkqIuRGjegkWfO/Be5+Swf2kYugpTtdO91X6sqfsqGYJBbdmQsEIxTt3w6e7Wra0cbHNU3Q== MIME-Version: 1.0 X-Received: by 10.202.78.68 with SMTP id c65mr9746316oib.47.1462198714215; Mon, 02 May 2016 07:18:34 -0700 (PDT) Received: by 10.202.79.195 with HTTP; Mon, 2 May 2016 07:18:34 -0700 (PDT) In-Reply-To: <1462136140.5535.219.camel@edumazet-glaptop3.roam.corp.google.com> References: <1462125592.5535.194.camel@edumazet-glaptop3.roam.corp.google.com> <865DA393-262D-40B6-A9D3-1B978CD5F6C6@gmail.com> <1462128385.5535.200.camel@edumazet-glaptop3.roam.corp.google.com> <1462136140.5535.219.camel@edumazet-glaptop3.roam.corp.google.com> Date: Mon, 2 May 2016 17:18:34 +0300 Message-ID: From: Roman Yeryomin To: Eric Dumazet Cc: Jonathan Morton , make-wifi-fast@lists.bufferbloat.net, "codel@lists.bufferbloat.net" , Dave Taht , ath10k Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] [Codel] fq_codel_drop vs a udp flood 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: Mon, 02 May 2016 14:18:34 -0000 On 1 May 2016 at 23:55, Eric Dumazet wrote: > On Sun, 2016-05-01 at 23:35 +0300, Jonathan Morton wrote: >> > On 1 May, 2016, at 21:46, Eric Dumazet wrote: >> > >> > Optimizing the search function is not possible, unless you slow down t= he >> > fast path. This was my design choice. >> >> I beg to differ. Cake iterates over the queues in the bulk and sparse >> lists, rather than all queues full stop. That=E2=80=99s a straightforwa= rd >> optimisation which covers the case in question here, and has no effect >> on the fast path. > > > Thats not going to help, sorry, if you have hundreds of flows in these > queues. (I had 200 TCP_STREAM running in my test, plus one hostile > UDP_STREAM) > > It is going to be _much_ slower, since you'll bring in cpu caches way > more memory, while disc spinlock is held. > > Better have a known cost of 1 cache line miss per drop, instead of 200 > cache line misses per drop. > > (4096 bytes to store q->backlogs[] array -> 64 cache lines. > If we drop 64 skb per pass, this averages to 1 cache line miss per drop) > > Listen, I never thought people were going to use fq_codel in some > hostile env. > > I simply designed it to be used in home routers, so I would not imagine > someone would be trying to kill its own Internet connection. Imagine you are a video operator, have MacBook Pro, gigabit LAN and NAS on ethernet side. You would want to get maximum speed. And fq_codel just dropped it down to 550Mbps for TCP (instead of 750Mbps) and to 30Mbps for UDP (instead of 900Mbps). So, again, it looks broken to me. Regards, Roman