From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x241.google.com (mail-oi0-x241.google.com [IPv6:2607:f8b0:4003:c06::241]) (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 5E02F3B260; Mon, 2 May 2016 10:09:49 -0400 (EDT) Received: by mail-oi0-x241.google.com with SMTP id w198so22993498oiw.2; Mon, 02 May 2016 07:09:49 -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; bh=+dLo2rwmUoTW/D1Bl7C1O0E9bLlCrvYAqvvV64c3MOg=; b=IqhFvFAsxV8XS75eMBQ4eip8nMAnsVvl1BhF6l71/HXGxU4ZJJSiJNzAMlOPul3F36 HRblhfpe1aasSXfhjO0z6fer+5QlsjL8jjTPBQr4XJFlcqbgvCIftNKI29QgRn4gqstb olQhsaEYXypyWOVAVdyZlBAUDXjP6H5WS2jzzRWICTlliUwXJYOZNQrGj+MAzj350kvG aQKBZ0bOCJ+A1iPmdDp+paibZ1cRTzZOZVYc9DpVlvL1YCWTZS5FI6mHl7JZDGPszHHE /TTgOpsZfFApCqlhknj8t/NuY6So+il+hl5dM2ThWo3BSv3zdywU9xo2pW4I0hqTYzXS hrfQ== 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; bh=+dLo2rwmUoTW/D1Bl7C1O0E9bLlCrvYAqvvV64c3MOg=; b=Vy1BbRKwOQ3PSTMaz6OxSEOe2R7mbm1YXlsz7Kr2aW/vVeEn+oGRNu2QbchHZznfgw eQhHanPqrB5zF3DQF0ecECDQReOwwb3V7KCZ/yCoesdRj3kUGveiP3mjQJg8aVdDiUoh dUxoVW4GE5FMd/aBk54mkqrB4Qw9Evcc4xI6nF2v+jGl+YwGrVvEE9zaNsw1fAwzI1dI euwk45+M/67J3hz9Vx7RVgblWW6bNp3NTKNK28baIDKBZJtDue563mbALfNTMWBfGSq4 2JOuuAAtlS8qzawx1KNOb/xdZqmhK1kHKGD/3F37bRqO8aCgMNxEKwUjlM/g4biswIHi c9ZQ== X-Gm-Message-State: AOPr4FV+u2mvYPmPJqflw81nBlAntjvux0plgDzOR1eZUrxpEqy4kX+bE+V3fkROb9QTVECMc0fqUsoXkcZLAA== MIME-Version: 1.0 X-Received: by 10.157.7.86 with SMTP id 80mr13666550ote.168.1462198188851; Mon, 02 May 2016 07:09:48 -0700 (PDT) Received: by 10.202.79.195 with HTTP; Mon, 2 May 2016 07:09:48 -0700 (PDT) In-Reply-To: <1462125592.5535.194.camel@edumazet-glaptop3.roam.corp.google.com> References: <1462125592.5535.194.camel@edumazet-glaptop3.roam.corp.google.com> Date: Mon, 2 May 2016 17:09:48 +0300 Message-ID: From: Roman Yeryomin To: Eric Dumazet Cc: Dave Taht , make-wifi-fast@lists.bufferbloat.net, "codel@lists.bufferbloat.net" , ath10k Content-Type: text/plain; charset=UTF-8 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 14:09:49 -0000 On 1 May 2016 at 20:59, Eric Dumazet wrote: > On Sat, 2016-04-30 at 20:41 -0700, Dave Taht wrote: >> >>> >> >>> 45.78% [kernel] [k] fq_codel_drop >> >>> 3.05% [kernel] [k] ag71xx_poll >> >>> 2.18% [kernel] [k] skb_release_data >> >>> 2.01% [kernel] [k] r4k_dma_cache_inv >> >> The udp flood behavior is not "weird". The test is wrong. It is so filling >> the local queue as to dramatically exceed the bandwidth on the link. > > Well, just _kill_ the offender, instead of trying to be gentle. > > fq_codel_drop() could drop _all_ packets of the fat flow, instead of a > single one. > > It is too cpu intensive to be kind to the elephant, since under pressure > fq_codel_drop() needs to be called for every enqueue. > > Really, we should not try to let inelastic flows hurt us. > > I can provide a patch. > So if I run some UDP download you will just kill me? Sounds broken. Regards, Roman