From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x242.google.com (mail-lf0-x242.google.com [IPv6:2a00:1450:4010:c07::242]) (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 9A2AE3B29E for ; Sat, 15 Apr 2017 10:54:18 -0400 (EDT) Received: by mail-lf0-x242.google.com with SMTP id i3so12347225lfh.2 for ; Sat, 15 Apr 2017 07:54:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=a7iQXteMee0isyRIi74KVOeku8b+wA5l3tuDNljacUI=; b=thMfoFZd5R1ROlAdrfmwLBqcO2BWFwVk2hw8zP0NMHCw12gJVjA+vWWXMyBjuSFwiU ZbpiONjoOL2pBzxuF/jijNpow8mBwJFCIRLKAjIJCTfp4loeLFMJVWClOyjSG617/hYs yqXESOaQEpnQKM/JfmlpIqZC7bouNVA8LjOdOZKyx1Vmv7ewXzFC4J9RGEWS3091xmu9 bCWjov4ZTNN5QP6V8fKVaJZlsBQ87NIvcL9yy9zdboZoGGfuhmxyTPWqrUOfNgGXrkyY HhM/GLf4sbN9M034iw8rbwvSx1OYQPJirADX1Yecn3nvM/4qzu8kQJ/t1vEw9VKGw2DB HP8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=a7iQXteMee0isyRIi74KVOeku8b+wA5l3tuDNljacUI=; b=WVJ9wNox8pGWuT0SQEqgJgEMbl8odU2MxRJ4AuYimMw0OSzkK94nQutCkw55h3hzry bQ2vothbqtgHiN6Te/gWWM7eMDLJ/RWkLt/OfRVq6SK1ifCsKANu2cV7dyGKexef0TVB Tz1dhbDAJOYC76NaMFgD7X+jzRz6chXiHg+TeKJAPEv9UsBMado+PzZc2QvHqR4eS0VM 7ojwlRiWy/zAytbVqBRUBttjuT8t7A3+aV5zCDG6Xs60ktc2eroRerQz/f/ma6UqdeJC Ophlze2JUoOqX/X55r4TmQyHlkpBh/Yl7kp7e5vWYEiers4xxO2LL5FJvxc+GoOtMb4S /fLg== X-Gm-Message-State: AN3rC/5AuNhI3cAciGqSzbzXKUn5sqxppRbTDpHX4a7eHNWFGjYyT2ef Y08GW6TLmu9YvA== X-Received: by 10.25.193.207 with SMTP id r198mr858624lff.62.1492268057094; Sat, 15 Apr 2017 07:54:17 -0700 (PDT) Received: from dmd8p3cg9n82sf-9wlp-4.rev.dnainternet.fi (dmd8p3cg9n82sf-9wlp-4.rev.dnainternet.fi. [2001:14bb:50:f8cb:88bd:5f2c:f27f:b24b]) by smtp.gmail.com with ESMTPSA id i23sm982668ljb.63.2017.04.15.07.54.15 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 15 Apr 2017 07:54:16 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Jonathan Morton In-Reply-To: Date: Sat, 15 Apr 2017 17:54:12 +0300 Cc: cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Harsh Lara X-Mailer: Apple Mail (2.3124) Subject: Re: [Cake] Cobalt Initial Target Value 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: Sat, 15 Apr 2017 14:54:18 -0000 > On 15 Apr, 2017, at 11:50, Harsh Lara wrote: >=20 > I was reading the code for the Linux implementation of COBALT. I = wanted to know where the target queue delay is being set initially in = the code. Both =E2=80=98target=E2=80=99 and =E2=80=98interval=E2=80=99 are treated = as parameters to COBALT in the same way as for Codel. They are thus = normally initialised in cake_set_rate(), rather than in COBALT itself. > Also, is there any recommended value for target? As a rule of thumb, set =E2=80=98interval=E2=80=99 to your expected = average path RTT (assume 100ms for general Internet traffic) and = =E2=80=98target=E2=80=99 to 1/20th of that. However, =E2=80=98target=E2=80=99 should also be high enough to permit = ordinary serialisation delay of an MTU-sized packet without triggering = the AQM. This clamping is part of what cake_set_rate() does, ensuring = =E2=80=98target' corresponds to at least 1.5 MTUs at the shaped rate. - Jonathan Morton