From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-x22c.google.com (mail-ob0-x22c.google.com [IPv6:2607:f8b0:4003:c01::22c]) (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 820D521F555; Tue, 16 Jun 2015 23:16:29 -0700 (PDT) Received: by obcej4 with SMTP id ej4so26717005obc.0; Tue, 16 Jun 2015 23:16:27 -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=pE8wPpC7XkhbOt0NKsyPHPs71H3yW6XYfRfzDILA3FI=; b=EYn8UbxoA2V3ktDYSunDytq3zyCirCSnYBIFjR4+LQ2KQl8XKcu1oLwFkbnncDEdaw ytYTesi5zhe+DkQFT0G5LpCqDjW7yi5ImNL7uD1Tyr9GVJSbQVZAb1hhxxXUuLcqHdSb ku+PKe7YlpFP7nangNVSxWCYvkQze0oSgNx/A7cIllW5rQccLe4CV3nFM23sym+wJkPR L4/96sb9gbzHaS3MfKcsw90oeEPIwpvkbU90iiiOZAg7TQWZqbF+gdG+AOzPq1NmvRwy TF/KSdeu10KBbIo8Lr6Qiuy/1TU0BZ7FZ8TWrG0R22i/hMLpoA2u5VvOKx6a17W9t0m4 /rhQ== MIME-Version: 1.0 X-Received: by 10.202.92.68 with SMTP id q65mr3106023oib.11.1434521787526; Tue, 16 Jun 2015 23:16:27 -0700 (PDT) Received: by 10.202.105.129 with HTTP; Tue, 16 Jun 2015 23:16:27 -0700 (PDT) In-Reply-To: <00270BE3-4932-4294-8917-8A9C2B462FCF@gmail.com> References: <00270BE3-4932-4294-8917-8A9C2B462FCF@gmail.com> Date: Tue, 16 Jun 2015 23:16:27 -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, "codel@lists.bufferbloat.net" , bloat Subject: Re: [Cake] Today's cake 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: Wed, 17 Jun 2015 06:16:57 -0000 Just when I thought it was safe to flash a router. Honestly. Your email landed not less than 5 seconds after I finished a build. On Tue, Jun 16, 2015 at 10:49 PM, Jonathan Morton w= rote: > I just put in three quite small tweaks to cake: > > 1) Codel now has a saturating increment for count, rather than a wrapping= one. > > 2) The active flow counter is now an atomic-access variable. This is rea= lly just an abundance of caution. It is not clear to me if this is needed, either. > 3) The overload drop routine should now be somewhat more efficient in mos= t cases, since it iterates over the active flows rather than the entire arr= ay. I haven=E2=80=99t measured how much of a difference it makes in practi= ce, but it should be positive. I was thinking that tracking the fattest 3 or so flows would suffice, there would be constant overhead in keeping that statistic handy and correct but constant overhead on figuring out where to drop on overload, also. > > Point 1 turns out to matter rather a lot under unresponsive loads, given = that count is only 16 bits. > > The =E2=80=9C50 up 1 down asymmetric=E2=80=9D test now produces the desir= ed results for the download stream *without* the need to prioritise the ack= s; Codel now reaches a steady-ish state where it drops enough of them to ke= ep everything moving, and this leaves more bandwidth in the up direction fo= r the 50 streams. > > The version of that test with a prioritised download stream reveals that = quite a lot of drops (as well as marks) are still occurring in the 50 strea= ms. This, to my mind, is a sign of too much aggression in the switch from = marking to dropping, but I need to work out the numbers to be more confiden= t about adjusting that. k. What bandwidth? I still disagree with you on count/2 because you are trying to hit the next harmonic, and agree with you that count-1 is unstable, but I will try to get some data instead. > > - Jonathan Morton > > _______________________________________________ > Cake mailing list > Cake@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cake --=20 Dave T=C3=A4ht What will it take to vastly improve wifi for everyone? https://plus.google.com/u/0/explore/makewififast