From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-x129.google.com (mail-lf1-x129.google.com [IPv6:2a00:1450:4864:20::129]) (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 35C2F3B2A4 for ; Mon, 10 Dec 2018 10:15:55 -0500 (EST) Received: by mail-lf1-x129.google.com with SMTP id v5so8249561lfe.7 for ; Mon, 10 Dec 2018 07:15:55 -0800 (PST) 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=VhUsy3gu/+LlYIQJoyeLQwbKBldjPiIvNQjrPi2cYbg=; b=YBfC68i83/4mS2LqDqgIxCE64ndsIuIE/6g4xGwHs25SCv0C8wCGM2cQmiBnsYD8k6 YqcuXHhC8tQtt69QJoKHh2vzppEAJlDWXg4Hq9H2/+/DvhfYIWfM0V6C9su2JK4gT8t9 YM0hNq9mLkzQCzoNibbqPBRW6fxVD6wR2F1HqGQxiVT3DHChvuVMzsBRuNYWl7YS1ZGM 26sKBUZdkoPtoGupqrzKChoXH+SxDJr2eJoVKnC965mYjZyXN7pZYYiq1ODPq3zkuyrY Am1gacLeVhSHs4Ru/Xfa+AYq1xh0o23PSanC6cJRZ8ZF8cyAtc9Sh/J/hBWJznQ3z+ZE VwoA== 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=VhUsy3gu/+LlYIQJoyeLQwbKBldjPiIvNQjrPi2cYbg=; b=J4lZk5UWZYgEmy3e8I/i0b6aZWSwS1olb3m4LxqRSj9MClHwReZ8TYEpiRDJquB93h NoMjFyGmrsJb0Gr3JvSkH/5Dm2Zn4a5OPO5NbQj9nO2+9KPVbtytbOIGrvwhDfuEUoHf vAOcorkIsm6jn6iXlXYEkTh4DhKzVs8U9YcShqsdy7jserz78e2D2gRMo1LvoXP6DEWR HdQxRCCI7WGZj2cHsSDlkgFQSm7x1gCRIbKCTx4C8qDMwMNeCZr7O6P9BOnA+Q+wrsFp sMEHwDmAQDdCABgzhY0gopq7wkkR/P+pfPzZiqWG3Qn0m/dr8389Sl0uX4YECwz1dzj6 Eb/w== X-Gm-Message-State: AA+aEWafU9ymwrdNgtzYi0lMZTiLyDNZLTgpPAPoG6ViNmBU5/BSyUGj IeXRzL5SWfO1v6Zxkgl1gU4= X-Google-Smtp-Source: AFSGD/VxcTELtyCv+4nRZH8phGpSr1Z1U+gJDz7IKCHPf1kF31IXgu8WJR1EbuFTyFoJvDL3zThu9A== X-Received: by 2002:a19:c115:: with SMTP id r21mr6926303lff.144.1544454953499; Mon, 10 Dec 2018 07:15:53 -0800 (PST) Received: from jonathartonsmbp.lan (83-245-234-248-nat-p.elisa-mobile.fi. [83.245.234.248]) by smtp.gmail.com with ESMTPSA id o88sm2187956lfk.38.2018.12.10.07.15.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Dec 2018 07:15:52 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) From: Jonathan Morton In-Reply-To: Date: Mon, 10 Dec 2018 17:15:50 +0200 Cc: Dave Taht , dave@taht.net, cake@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <4487BE09-D5D9-4F54-B652-409E50CB4BF4@gmail.com> References: <87va4nzsn4.fsf@taht.net> <6578A0D1-FF6A-474E-A6D5-98185F98CB45@gmail.com> <08381337-F99A-46D1-87AF-B0F71A8753BC@gmail.com> <949D58FF-9C2F-4516-8547-20A712EC0C92@gmail.com> <271B3584-068F-4FED-B037-B8E920A9EE55@gmail.com> <70BDD881-B509-43FE-81BB-E9C4B1145FA1@gmail.com> <8467184E-7C35-4AFE-9CC6-292215022FDB@gmail.com> To: Jendaipou Palmei X-Mailer: Apple Mail (2.3445.9.1) Subject: Re: [Cake] COBALT implementation in ns-3 with results under different traffic scenarios 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: Mon, 10 Dec 2018 15:15:55 -0000 > On 10 Dec, 2018, at 2:30 pm, Jendaipou Palmei = wrote: >=20 > As suggested, we changed the NIC buffer size to 1 packet for the = simulation and also tried these different buffer sizes: 10, 50 and 75. >=20 > The default NIC buffer size in ns-3 is 100 packets. >=20 > Additionally, we also enabled BQL and tried. >=20 > We see that the link utilization gets significantly affected when we = keep the NIC buffer size small. Yes, that's what I'd expect to see from Reno-type congestion control, = and is one good reason why alternatives to Reno were developed (eg. = Compound, CUBIC, BBR). You may wish to explore what happens with = Compound and CUBIC, once your basic measurement methodology has matured. I would suggest using BQL, since it's available and represents a = realistic deployment. If you were to add TCP (or parallel UDP/ICMP) RTT measurements, you'd = see that the peak latency was correspondingly improved by removing the = dumb FIFO hidden within the NIC. I estimate that a 100-packet buffer = accounts for about 120ms of latency at 10Mbps, which should definitely = be visible on such a graph (being almost 250% of your baseline 50ms = latency). Since latency is the main point of adding AQM, I'm a little surprised = that you haven't already produced graphs of that sort. They would have = identified this problem much earlier. At present you only have COBALT graphs with the small NIC buffer. For a = fair comparison, Codel and PIE graphs should be (re-)produced with the = same conditions. The older graphs made with the large NIC buffer are = potentially misleading, especially with respect to throughput. - Jonathan Morton