From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vn0-x22c.google.com (mail-vn0-x22c.google.com [IPv6:2607:f8b0:400c:c0f::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 027B621F279; Thu, 30 Apr 2015 07:52:49 -0700 (PDT) Received: by vnbf1 with SMTP id f1so7480842vnb.5; Thu, 30 Apr 2015 07:52:42 -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; bh=w0Sv4ou1DMBVjdQ0URhBCQv80fPNLAIRH3QTVuvfd1Y=; b=B5/rstmnax3qi4Q3JK4gZgfAEI1dv/hKd1NbnQFMjY0se6eJ8ZP3BahzWVwWdq+Cv7 e24YUrRm/UtfgHFho+QMEFSKbzclA7Pe/507Y5ZPCLuovDISsPBYi8H87cwuGfvttTKf amSqdH75AeuoFSEGXKrubJWRlje4SosQj/YiDeCo9PSwlwsabYFDjwg0AXYw4LczKfTI H9a6pOWRNQ+IEq+B6sw4lPIuA+scCOro/O9x7WtVWBKmNTDuBjkNvEJbvlHqgkPQsZSd 6d8gui8QJbo3ZPsU9RZVuRE6SON52QmLr1HEn3SelHnXkDxxFBL4+O5NlIO2H7CmKACe q/rQ== MIME-Version: 1.0 X-Received: by 10.52.33.180 with SMTP id s20mr8211920vdi.35.1430405562551; Thu, 30 Apr 2015 07:52:42 -0700 (PDT) Received: by 10.52.12.167 with HTTP; Thu, 30 Apr 2015 07:52:42 -0700 (PDT) Received: by 10.52.12.167 with HTTP; Thu, 30 Apr 2015 07:52:42 -0700 (PDT) In-Reply-To: References: Date: Thu, 30 Apr 2015 17:52:42 +0300 Message-ID: From: Jonathan Morton To: Dave Taht Content-Type: multipart/alternative; boundary=20cf3079baae70d5410514f23fcd Cc: cake@lists.bufferbloat.net, "cerowrt-devel@lists.bufferbloat.net" , bloat Subject: Re: [Cerowrt-devel] [Cake] documentation review request and out of tree cake builds for openwrt/etc. 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: Thu, 30 Apr 2015 14:53:24 -0000 --20cf3079baae70d5410514f23fcd Content-Type: text/plain; charset=UTF-8 I'm not concerned about aggregation effects on cable, because it's not station specific as it is on Wi-Fi. It might be a source of one extra access grant delay at most; after that there'll be enough packets in the modem's FIFO to justify a full sized grant. Here the modem's buffer really does exist for a good reason, and we can rely on it to do the job. I'm also not concerned about ack bunching, because realistically that isn't really caused by FQ. Given a 10:1 bandwidth ratio, and a 3:1 delayed ack factor, there'll be 3.33 acks for each data packet in the slow direction, while at our default 300 quantum the DRR will cycle five times per data packet. So acks for a given flow will only be delivered bunched if they arrived bunched. - Jonathan Morton --20cf3079baae70d5410514f23fcd Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

I'm not concerned about aggregation effects on cable, be= cause it's not station specific as it is on Wi-Fi. It might be a source= of one extra access grant delay at most; after that there'll be enough= packets in the modem's FIFO to justify a full sized grant. Here the mo= dem's buffer really does exist for a good reason, and we can rely on it= to do the job.

I'm also not concerned about ack bunching, because reali= stically that isn't really caused by FQ. Given a 10:1 bandwidth ratio, = and a 3:1 delayed ack factor, there'll be 3.33 acks for each data packe= t in the slow direction, while at our default 300 quantum the DRR will cycl= e five times per data packet. So acks for a given flow will only be deliver= ed bunched if they arrived bunched.

- Jonathan Morton

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