From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x229.google.com (mail-qk0-x229.google.com [IPv6:2607:f8b0:400d:c09::229]) (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 DB6AD3BA8E; Wed, 29 Nov 2017 13:48:48 -0500 (EST) Received: by mail-qk0-x229.google.com with SMTP id d66so5758320qkg.1; Wed, 29 Nov 2017 10:48:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=CZUsMDYk375ltBjQn6l4qkULMBfCXi5WWbSVEWnCPnM=; b=o7IyVZBFckmaEDpTcQj++W181BxLcMQQXazU2WsXTZesLd1lZOmbhnsxOWpup5SzLL XSOJa3BQHjoeYP2Xh8jKrOGZRn1N8FA3dx4kCyVeQvwyhmPzBaDsc6BYAV36WjK8N84W PkELlyvWIueLpl0ZunP7LRVT9HV7aw9KIGsAc6UhA3jhsPFdaFP2V9HIT9WfNkEfEu8O f62TFu5SpBQl/wQl8cTcJzklVj4caTAmXrHq4IR6aIInMhhXlOztQdJIrIOBLCRdvDh4 ad6oSK7eBP0+ku3/xxQWEjbij1gNfZwToOW74tWKaY4arj6aBf8DvXCMQzeap0+0Nd5d 4J/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=CZUsMDYk375ltBjQn6l4qkULMBfCXi5WWbSVEWnCPnM=; b=dBW88muYg4QPO4/jkqnGEmR7F6hjkF1Dnyw1SaQc8LEMZ6UAM3AHG84tETPtBKhVSC harchOTElZoyTZnhqBytbbbnvmgmiJAwd7YX136vFZoHZXIOvPqQoU0CifVYAu702E2C i7HiWXcHmqgnIqRFVbRl84lGiy4yed5tDsvayeOVWIrjXwxvJgqhkrgx6vvGLnF+9y0L xfVXe5Pg9mgWvqzSjs0oQT1C6k5Xn6J8aeho8lYHG7jkFk0GnYrcKPWBFIAHiuFhnorH IbvmmavDCCN8JVpB6pEGD4S6dBFUl5s3n6i/diM46QRA1J/ap/QEKb4eGL8ZSgBbN54/ G0Nw== X-Gm-Message-State: AJaThX5I4UakaT5B+0G2635ouguUlcGnIEfeL1oZQeoMOk8+MfjGZUSe osEn/PRLBOb/y115JJFHFAk6nSuHOasV6Wr+55Y= X-Google-Smtp-Source: AGs4zMbJAS5WmORqhC94xn5bJQ3G4IXe9+2IyYhA8+0svpGhUfzYTPMtnLvpK3qiOm4YY9TWBKfy7N0umdWEJus856M= X-Received: by 10.55.154.85 with SMTP id c82mr5966231qke.327.1511981328471; Wed, 29 Nov 2017 10:48:48 -0800 (PST) MIME-Version: 1.0 Received: by 10.12.193.93 with HTTP; Wed, 29 Nov 2017 10:48:48 -0800 (PST) In-Reply-To: <7izi75q6rj.wl-jch@irif.fr> References: <7izi75q6rj.wl-jch@irif.fr> From: Dave Taht Date: Wed, 29 Nov 2017 10:48:48 -0800 Message-ID: To: Juliusz Chroboczek Cc: bloat , Cake List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Cake] [Bloat] benefits of ack filtering X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 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, 29 Nov 2017 18:48:48 -0000 On Wed, Nov 29, 2017 at 10:28 AM, Juliusz Chroboczek wrote: >> Recently Ryan Mounce added ack filtering cabilities to the cake qdisc. >> The benefits were pretty impressive at a 50x1 Down/Up ratio: > > If I read this posting right, you're only measuring bulk performance. > What about interactive traffic, when there's only one or two data segment= s in > flight at a given time In this design, you can only filter out an ack when you have a queue of the= m. I am thinking saying "filter" has been misleading. Tho plenty stateless ack filters exist. ack-queue-compression? >> I'd rather like to have a compelling list of reasons why not to do >> this! > > I haven't looked at Cake in detail, and I haven't put much thought into > ACK filtering, but off the top of my head: > > - not risking breaking any of the TCP-related algorithms that depend on > ACKs arriving in a timely manner (AIMD, Nagle, Eifel, etc.), > especially in the case of just one segment in flight; > - not contributing to the ossification of the Internet by giving an > unfair advantage to TCP over other protocols; > - limiting the amount of knowledge that middleboxes have of the > transport-layer protocols, which leads to further ossification; > - avoiding complexity in middleboxes, which leads to a more brittle > Internet; > - not encouraging ISPs to deploy highly asymmetric links. I'll add these to my list! > > This is not my area of expertise, and therefore I don't feel competent to > have an opinion, but I think that before you deploy ACK filtering, you > really should consider the worries expressed above and whatever other > worries more competent people might have. been worrying ever since I touched the wet paint! > -- Juliusz --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619