From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-x22c.google.com (mail-lj1-x22c.google.com [IPv6:2a00:1450:4864:20::22c]) (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 6C3E43B2A4 for ; Wed, 15 Jul 2020 20:37:33 -0400 (EDT) Received: by mail-lj1-x22c.google.com with SMTP id q4so5035098lji.2 for ; Wed, 15 Jul 2020 17:37:33 -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=+SWcUEhp+Po4EL2337nSm3RMYdecV4BPvYMTfCjXUtE=; b=GCxmeaaOmP23VWhF6v6ikabxNv/cadkB0JO4GsXTUAapoQjBJ0pqYmJ+YfZH19Dy/W BI1sPQ5KnF/Y00myEJWn8ViZysGhYfeJT7TmAyxHIYT8c+J82MpMP5HprIpXPYAHkv+w UChBepaSHsOvaIzIHvr9W8kFDzf7tKbN7m8ntDbLAol33yIBQtvO6zeXLzNden67R2zc FB1VQvpLeAHd52XkcYfiZPAd7suVoA+yNVddYjJWUJBE0Wg0tmjB6szacXWMH7PsjNAt dsHfbG12jRNf43Qn+qf9OSYxbwY9h8zngzUKodeG4yuUBvdyHoMNidF0T2vYLSuCe+VL lpMw== 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=+SWcUEhp+Po4EL2337nSm3RMYdecV4BPvYMTfCjXUtE=; b=C0kn6En92owfnty5YY1a+Mh83sAGQw5pAp3TxulCS0FBQtk+Tzx1GrxU/QIdbNkJzP B6G0mFnJS3Xw4y739NS+40NXvzvnP3WWnFYVs/fP7q2zC2wMvdLl208xkKjTh3/UW2ru CRZ+ftU302WaMjE9Yzs4xe3Uk9sOqkmM8cMO09YdBAPAnYrN8g2FYLphBwwqnehrYr23 qVwTq91+zUiU35So67JlxfcrKi63KqfnuduYEny/S40Nr9I/mfY/+BebCEoRDvcuhiWO EkTTqVO0H9zEAgmQeXNbX8e39AkvXiKJ0aY5AGWLd3LHIMQpeI4xs1+vTgXQld+hF5Wb uPvw== X-Gm-Message-State: AOAM530gJkbw22Rq8deLEoL24Wv0Tn4dKbM+Zgop6eJDbjbNqD5omQzQ Pd5bez2MU+5GccaOO6++HEE= X-Google-Smtp-Source: ABdhPJzJZ1wZb2MAQu1R0wvQ7HDLovesG70J9MI7z+9LKrE3ml5P7w/xmmxpXysVTg3gGO2HEwfdLQ== X-Received: by 2002:a2e:9a47:: with SMTP id k7mr761031ljj.96.1594859852238; Wed, 15 Jul 2020 17:37:32 -0700 (PDT) Received: from jonathartonsmbp.lan (83-245-252-162-nat-p.elisa-mobile.fi. [83.245.252.162]) by smtp.gmail.com with ESMTPSA id v19sm811059lfi.65.2020.07.15.17.37.31 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Jul 2020 17:37:31 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.5\)) From: Jonathan Morton In-Reply-To: Date: Thu, 16 Jul 2020 03:37:30 +0300 Cc: "bloat@lists.bufferbloat.net" Content-Transfer-Encoding: quoted-printable Message-Id: <156954CF-BCBC-4B0C-9C42-A2A6F2450185@gmail.com> References: To: Michael Yartys X-Mailer: Apple Mail (2.3445.9.5) Subject: Re: [Bloat] Phoronix: Linux 5.9 to allow FQ_PIE as default X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Jul 2020 00:37:33 -0000 > On 16 Jul, 2020, at 12:58 am, Michael Yartys via Bloat = wrote: >=20 > Are there any major differences between fq_codel and fq_pie in terms = of their performance? I think some tests were run some time ago which showed significantly = better behaviour by fq_codel than fq_pie. In particular, the latter = used only a single AQM instead of an independent one for each flow. I'm = not sure whether it's been changed since then. The only advantage I can see for PIE over Codel is, possibly, a = reduction of system load for use of the AQM. But fq_codel is already = pretty efficient so that would be an edge case. In any case, it is already possible to chose any qdisc you like (with = default parameters) as the default qdisc. I'm really not sure what the = fuss is about. > And how does the improved fq_codel called cobalt, which is used in = cake, stack up? COBALT has some modifications to basic Codel which, I think, could = profitably be backported into fq_codel. It also has a particular extra = mode, based on BLUE, for dealing with unresponsive traffic (that = continued to build queue even after lots of ECN signalling and/or = Cdel-scheduled packet drops). It is the latter which inspired the name. For the other major functional component of fq_codel, Cake also has a = set-associative hash function for allocating flows into queues, which = substantially reduces the probability of hash collisions in most cases. - Jonathan Morton=