From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x236.google.com (mail-ob0-x236.google.com [IPv6:2607:f8b0:4003:c01::236]) (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 628D921F72D for ; Fri, 30 Oct 2015 14:34:12 -0700 (PDT) Received: by obbwb3 with SMTP id wb3so55048264obb.0 for ; Fri, 30 Oct 2015 14:34:12 -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=kmQzLwpgUMkMqpJvH53UR91Ok0FX8kkpSYUwopNrsl4=; b=BgYQw/m1NeysVxLYjc6wW6Mx9S/cOxah3VWONggkRwC27csZy19mez9xCH21EnnGEu TCpxUpbyHEQ0iE8dFwMlkF0zbD/JHKRa+a13GSqF1Yo7HRVNcpgv5FS9b86MstkKPvav 5F335Z3EZcXTsyWEYWm2+kCY2XIvJHJA6XWBuvw7XcwsXfYoC7CbOXYveAPuCNTrdpbv Jr0tAUIvs9XdPNEeeLG6tHAhR4ffcjNaRmHH4rSQ3T1m1lzt7ezVUoOdIxii9PpO66rq XXVFvG+9OVNyVts9sO/4yiML9hI12IgunAB41aDY5FnMgHa+SsALfftqup5SpLrKOkuQ XVyw== MIME-Version: 1.0 X-Received: by 10.60.176.36 with SMTP id cf4mr7745283oec.9.1446240852242; Fri, 30 Oct 2015 14:34:12 -0700 (PDT) Received: by 10.202.61.133 with HTTP; Fri, 30 Oct 2015 14:34:12 -0700 (PDT) In-Reply-To: <5632591A.5040403@darbyshire-bryant.me.uk> References: <87a8r4mji9.fsf@toke.dk> <5632591A.5040403@darbyshire-bryant.me.uk> Date: Fri, 30 Oct 2015 17:34:12 -0400 Message-ID: From: Dave Taht To: Kevin Darbyshire-Bryant Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: cake@lists.bufferbloat.net Subject: Re: [Cake] Running Cake at long RTTs X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Oct 2015 21:34:35 -0000 Good spot, thx! Dave T=C3=A4ht I just invested five years of my life to making wifi better. And, now... the FCC wants to make my work, illegal for people to install. https://www.gofundme.com/savewifi On Thu, Oct 29, 2015 at 1:36 PM, Kevin Darbyshire-Bryant wrote: > > > On 27/10/15 15:14, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >> So Dave and I did a bit of testing of Cake at a 1-second base RTT. That >> showed that, compared with a straight FIFO queue (with a sufficiently >> large buffer), throughput was suffering quite a bit under Cake, >> especially at large bandwidths. We did two changes to fix this: >> >> - Turn the hard packet queue size into a lower bound rather than an >> upper bound. >> >> - Scale the target to be 1/16th of the interval. >> >> The first change allows Cake to actually reach the target throughput, >> but it still takes a long while to get there. With the second change, we >> actually get the desired behaviour. The attached plot shows the >> difference, with the solid line being before the change and the dashed >> line being after the change. >> >> Patch attached. >> >> -Toke > > That patch is really going to behave strangely indeed. You end up with > b->cparams.interval =3D max(rtt_est_ns + b->cparams.target - > ns_target,b->cparams.target * 8); > b->cparams.target =3D max(max(byte_target_ns, ns_target), > b->cparams.interval >> 4); > > So interval no matter what happens takes note of 'cparams.target' which > hasn't yet been set (on first run is 0) > And target wants to take interval/16, which may be based on the previous > calculation. Erm. Needs more thought. > > My brain isn't working at the moment due to illness, but recursively > playing with bandwidth settings on cake is most entertaining at the > moment ;-) > > Kevin (dead with cold/high as a kite on cold drugs) > > > > > > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake >