From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ia0-x233.google.com (mail-ia0-x233.google.com [IPv6:2607:f8b0:4001:c02::233]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id AF69721F1A6; Wed, 8 May 2013 15:55:00 -0700 (PDT) Received: by mail-ia0-f179.google.com with SMTP id g4so2483104iae.24 for ; Wed, 08 May 2013 15:55:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:message-id:subject:from:to:cc:date:in-reply-to :references:content-type:x-mailer:content-transfer-encoding :mime-version; bh=kwQGkhq9VBRK8r91/ssPFOFpnld0vUQUFtWNwN1PY9I=; b=l0oVZGO9wR31uWrxLzYyIO/Nm8WqAQP4gTSYAt7KrrQv+7fsLv4ERb4rxUq2qwns1o xqN+2nMr1YZ23uDwW+9FsqH2ySOS8h6NoTaie8TcMouaxe5Af2fLkUsoiCIUKuLiFw3k sLipLB2d//RUFrzvuecmwPjcqQlUO7zk65WYbhliB+ZLgOntS7znNZ9MOELpjYFccO7n eaOljW6fPqEOP2gPBJ/DL+/t9z93jsxBEqCY7sb77kLd0YI84o1JZpaBva7jUPrjx6Dm 2ipGmiu/ggjwqsjmULAe8RLyHVjfcwhOgH1Y62vIYyhZFh6akwn//2QrBQYf15FTMfUl 2uXw== X-Received: by 10.42.90.72 with SMTP id j8mr2860932icm.34.1368053700118; Wed, 08 May 2013 15:55:00 -0700 (PDT) Received: from ?IPv6:2620:0:1000:3304:6df9:2c99:8b77:70ad? ([2620:0:1000:3304:6df9:2c99:8b77:70ad]) by mx.google.com with ESMTPSA id d9sm3612883igr.4.2013.05.08.15.54.58 for (version=SSLv3 cipher=RC4-SHA bits=128/128); Wed, 08 May 2013 15:54:59 -0700 (PDT) Message-ID: <1368053697.13473.28.camel@edumazet-glaptop> From: Eric Dumazet To: Dave Taht Date: Wed, 08 May 2013 15:54:57 -0700 In-Reply-To: References: <19404.1367933465@sandelman.ca> <1367958622.13473.10.camel@edumazet-glaptop> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Cc: Wes Felter , codel@lists.bufferbloat.net, cerowrt-devel@lists.bufferbloat.net, bloat@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] [Bloat] Latest codel, fq_codel, and pie sim study from cablelabs now available 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: Wed, 08 May 2013 22:55:01 -0000 On Wed, 2013-05-08 at 15:25 -0700, Dave Taht wrote: > Heh. I am hoping you are providing this as a negative proof!? as the > strict prioritization of this particular linux scheduler means that a > single full rate TCP flow in class 1:1 will completely starve classes > 1:2 and 1:3. > > Some level of fairness between service classes is needed too. My most > common setting for the "cake" shaper has been 20% minimum for the > background traffic, for example. I am unsure if codel is really the > right thing for the highest priority qdisc, as everything > PRIO qdisc does strict priority, like pfifo_fast. If your high prio traffic is also using 100% of the bandwith, then there is a fundamental problem about classifying this so called high prio traffic. On my hosts, high prio traffic uses less than 0.1 % of the bandwidth, so I do not need to have DRR kind of setup. And the low priority traffic has no minimum guaranteed bandwidth. There is no 'magic solution' for every needs. The solution I gave is good enough if you need to have some strict priorities, as a replacement to current pfifo_fast, and if all traffic is not miss classified. A setup using DRR instead of PRIO is also possible.