From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x22d.google.com (mail-ob0-x22d.google.com [IPv6:2607:f8b0:4003:c01::22d]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id D472821F347; Sun, 14 Jun 2015 11:24:53 -0700 (PDT) Received: by obbgp2 with SMTP id gp2so50883358obb.2; Sun, 14 Jun 2015 11:24:52 -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-type:content-transfer-encoding; bh=QO2uoOzepKvIfyzpRR0goLTt39ikomrYLRi/75SMcno=; b=qRRGW22JD6V2C5UpEAv7vKOtgSbTo2m/5oCxbtmjpkwbajutIHnvlbmrh9ptxksl0N LZE+nueEBO45VXpxe2GTApidNnlMpNtGweakLA0nTAPknbP3ptxc+cTUUFVrnKB5eWC/ Hwh82hNCTR5QhlLoinP4aePAi7fLBNw4DfYhKe89hSwb+06Qui8CQTGyDguDPJTbL0MM HzoQOADydzyNctaAtyN84TUcYnsZk1jdvwlWmpFBZ9rMgv30N8pYHLxBowTAnBNo0/Nx jFkNkxhQ8tt/zhvtzkJS7nowcdaSH+BS9zSPNEfrxIvlGslaj4JuQGmL4Mh4Ml2b1o0q Xlrw== MIME-Version: 1.0 X-Received: by 10.202.91.212 with SMTP id p203mr19252207oib.108.1434306292914; Sun, 14 Jun 2015 11:24:52 -0700 (PDT) Received: by 10.202.105.129 with HTTP; Sun, 14 Jun 2015 11:24:52 -0700 (PDT) In-Reply-To: References: <0CFA8991-9F5E-4988-82ED-6CA0E4E08676@gmail.com> Date: Sun, 14 Jun 2015 11:24:52 -0700 Message-ID: From: Dave Taht To: Jonathan Morton Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: cake@lists.bufferbloat.net, Alan Jenkins , "codel@lists.bufferbloat.net" , "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Cerowrt-devel] [Cake] openwrt build available with latest cake and fq_pie X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 14 Jun 2015 18:25:23 -0000 On Sun, Jun 14, 2015 at 11:07 AM, Jonathan Morton w= rote: > >> On 14 Jun, 2015, at 20:38, Dave Taht wrote: >> >>> Every time Codel triggers the dropping state, it will mark or drop at l= east one packet, and increment count by that number. With count decremente= d only by 1 on recovery, it will effectively remain constant *if*, by some = miracle, the queue empties before the second signal was sent; it cannot dec= rease between episodes unless it resets or wraps. >> >> It aint a miracle, it is hopefully within an rtt. > > No, it is *at minimum* one RTT. It takes that long for the congestion si= gnal to reach the receiver, be reflected back to the sender, the sender=E2= =80=99s reaction to *begin to* appear at the queue. Then the queue *starts= * to empty, if the signal is what=E2=80=99s required to make it do so. Flows, btw, do end quite rapidly in the real world. What was it, 95% of all web flows ended inside of IW10? Dropping a packet at the tail end of an ending flow forces a retransmit. Far too much of our testing and thinking is oriented to full rate flows. That is what I meant by "hopefully". I would like to build a test that consisted primarily of short flows, one that hopefully looked more like normal traffic. >> When resuming the drop phase of codel, it is almost *already* too late >> to catch that burst incurring the latency. > > Yes, but that=E2=80=99s what FQ is for. And ELR, if we ever get that pro= perly started. > >> Sometimes I think we need to do away with the count idea and measure >> slopes of curves instead, and "harmonics=E2=80=9D. > > >> Is there any reason why the decrease couldn't be some sort of decay? >> I.e. a function of how long ago the drop state was exited? > > Such things are theoretically possible, but require further thought to de= termine how best to do them. > > - Jonathan Morton > --=20 Dave T=C3=A4ht What will it take to vastly improve wifi for everyone? https://plus.google.com/u/0/explore/makewififast