From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-x233.google.com (mail-lf0-x233.google.com [IPv6:2a00:1450:4010:c07::233]) (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 6C6143CB3D for ; Thu, 19 Apr 2018 05:32:39 -0400 (EDT) Received: by mail-lf0-x233.google.com with SMTP id d20-v6so6799929lfe.3 for ; Thu, 19 Apr 2018 02:32:39 -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=cLge1WjjihOU7JzJG3i7noruP11RVEcQXoWO+RfJ+gA=; b=D0JyVUUhuWsF401ApslGbv2WotoY7zEsZxfrJsX3nOr0AIJq2IhfjTjq31HdD9vZVf S9/eVwKYNkehpTGvXOAzBiBMUiaOzMEVX8u0IvBLgsSOGxNyGnlel2IibOYQEKDKvF2l XamkNcBNx4Cn8wQ8NQciJrxDgVwaJ4X8BsL+ugpO1N4t26yrare4QSXmcFP7fIKJgaN0 VClix4BHxvPx7JTVDGUgwNzuJbVhrYyXIe3pDWcCDwS/2Po/9IPCMn0V8BXr9RJAhONc XwgJZBHSeRlW+PZcfTlIxIWdKFEHQHDZDIs7BV/aZ0EDlbsG9ncxeG5o7gCd8vJoBmjD iMJg== 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=cLge1WjjihOU7JzJG3i7noruP11RVEcQXoWO+RfJ+gA=; b=X/7Mmse3yjDPYXXPbXDTyx8FWt741H11aQXMHqAb1d+7sFE0vOMDEuSd8BtKvLijO/ 87eKLcvqmDlRAmHbROBLsieTkjfDLnKFjsILy8Ra4K+NGdjPmRX/LJ5Ty9SNgEGrF8o4 ljjY3N5ZuSjJTCibSDth3PMsl9DNdEOmr6iJDTvJaWZ5wMPDe+FJQi1H69aUdHA8pOvn uZqfXVRUqv8AsHH8F8RCQHWSi5ZPkg+q2rHAeeUd+e+NgqSUFiiuTs/IdRSpZx/aLNtt uwSAQB+3HtnzVA0Mlg1cytcxwewgHRBV/Zg2hwhLj7+qPoouwiwVSh0j+xx9MxPw9Boz amSA== X-Gm-Message-State: ALQs6tCBYJaq8IsHqz9sevEpYEkpzMf8afdIAOajXuLWE10p4cLssrLZ MAVe0ExpD2gvHdI1YgJzR7Y= X-Google-Smtp-Source: AIpwx48FuLJr4GxAuYqwrXmFGhaRJRyaB4khOdhwi0mgRjyPGw+z+ESZP45Q8EWYR8KGNPmhzxZg8g== X-Received: by 10.46.147.78 with SMTP id m14mr3634330ljh.120.1524130358248; Thu, 19 Apr 2018 02:32:38 -0700 (PDT) Received: from [192.168.239.216] (83-245-234-255-nat-p.elisa-mobile.fi. [83.245.234.255]) by smtp.gmail.com with ESMTPSA id o203-v6sm653789lff.25.2018.04.19.02.32.36 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 19 Apr 2018 02:32:37 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) From: Jonathan Morton In-Reply-To: <871sfb1rg5.fsf@toke.dk> Date: Thu, 19 Apr 2018 12:32:35 +0300 Cc: David Lang , cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <130F35DD-8AC7-4AE8-B7AB-82AE5B2F7653@gmail.com> References: <87vacq419h.fsf@toke.dk> <874lk9533l.fsf@toke.dk> <87604o3get.fsf@toke.dk> <578552B2-5127-451A-AFE8-93AE9BB07368@gmail.com> <87r2nc1taq.fsf@toke.dk> <0BB8B1FD-6A00-49D6-806E-794BD53A449F@gmx.de> <3457DD8E-0292-4802-BD1E-B37771DCADA2@gmail.com> <87fu3s1om2.fsf@toke.dk> <5BD20E12-2408-4393-8560-3FDA52D86DB3@gmail.com> <7EC1A95B-B398-451D-A234-E9C43DC34829@gmail.com> <871sfb1rg5.fsf@toke.dk> To: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= X-Mailer: Apple Mail (2.3445.6.18) Subject: Re: [Cake] A few puzzling Cake results 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: Thu, 19 Apr 2018 09:32:39 -0000 > If you turn off the AQM entirely for the > first four packets, it is going to activate when the fifth packet > arrives, resulting in a tail loss and... an RTO! That isn't what happens. First of all, Cake explicitly guards against tail loss by exempting the = last packet in each queue from being dropped. If a tail loss and RTO = actually occurs, it's extremely unlikely that Cake caused it, unless = it's been driven far beyond its design load in terms of flow count. Secondly, and as you should very well know, Codel only starts marking or = dropping when the *standing* queue exceeds the threshold set. COBALT = implements that logic in a different way to the reference version, but = it's still there. It's not a case of the fifth packet in a flow getting = dropped, but of a five-packet standing queue being the smallest that = *can* experience drops. So please don't strawman this. - Jonathan Morton