From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x231.google.com (mail-qk0-x231.google.com [IPv6:2607:f8b0:400d:c09::231]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 01EB221F412; Thu, 9 Apr 2015 14:35:14 -0700 (PDT) Received: by qku63 with SMTP id 63so381832qku.3; Thu, 09 Apr 2015 14:35:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:content-type:message-id:mime-version:subject:date:references :to:in-reply-to; bh=215+28jtkLneqRUA0FPXtLInKb/A76QEsY3pe0sBNEo=; b=sG8BU4wzc52X88Q0hEFDPAXCdQLNVZxft7TcSiOOeHKNrDe0/5iHLCcmLQPmNMv/ZW iFFT31w5Tb7QR8bwVaBPQ22/gATP7tdj4LzKA0q+bU7HCvK10IBcTKo8B5/GL/NOky3j v2N+11EJVvtM8hTxihsUsKREgx8cR73tt5VQbhzn0yeC1R2tzIxwhdrnFf5IOYYS7hJN uoYrC1bRQi/1L6ZsQXTDA/YA4ccRvDPmzQoqx9bGpjMLnkgiWsx2ik5x2O2ZDl9PvW5L v1kk0CyHL157vSTCT1UCJkj8zMEV0lV6xtKITyUYGDoDyTzU0/JMxni7nV2eWMZ6dXH0 taoQ== X-Received: by 10.140.49.11 with SMTP id p11mr15873062qga.60.1428615313368; Thu, 09 Apr 2015 14:35:13 -0700 (PDT) Received: from richs-mbp-11656.home.lan (pool-71-241-215-163.port.east.myfairpoint.net. [71.241.215.163]) by mx.google.com with ESMTPSA id 69sm10818834qkr.41.2015.04.09.14.35.12 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 09 Apr 2015 14:35:12 -0700 (PDT) From: Rich Brown Content-Type: multipart/signed; boundary="Apple-Mail=_A577639C-B154-4CD1-BAD1-A3B8FE688F8C"; protocol="application/pgp-signature"; micalg=pgp-sha512 Message-Id: <67BE685A-724C-45D7-A619-EC49498AF165@gmail.com> Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Date: Thu, 9 Apr 2015 17:35:09 -0400 References: <2E760E83-7224-4B9B-B918-B3EAD578E831@gmail.com> To: bloat , cerowrt-devel In-Reply-To: X-Mailer: Apple Mail (2.1878.6) Subject: [Cerowrt-devel] Questions about the use of HTB & fq_codel in simple.qos, simplest.qos 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: Thu, 09 Apr 2015 21:35:43 -0000 --Apple-Mail=_A577639C-B154-4CD1-BAD1-A3B8FE688F8C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 I've been thinking about the message we're sending re: = QoS/prioritization vs SQM, and I'm not clear on what our story is. = Here's what I understand: - On one hand, we say that good SQM algorithms (fq_codel, for example) = will do an astonishingly good job of minimizing latency without any = parameters (except perhaps link speed for slow bottlenecks) - On the other hand, our example sqm-scripts (simplest.qos, simple.qos) = have a HTB based shaper installed that (if I understand Dave T=E4ht's = description below) seems designed to limit the rate of various kinds of = traffic before it gets to fq_codel. (The HTB shaper would, a priori, = require some kind of configuration/parameter.) My questions: - Why do we provide an HTB-based shaper in simple.qos and simplest.qos? - Do the shapers in these sqm-scripts actually limit bandwidth for = various kinds of traffic? Might that not leave unused bandwidth? - Or do they just shunt certain packets to higher or lower priority = fq_codel tiers/bands/levels (terminology used in Dave's note below)? - And if the latter, how does the "link" (I'm not sure of the proper = term) know which of the tiers/bands/levels to dequeue next? I'll state up front that I'm not entirely clear on the distinction = between shapers, qdisc's, IFBs, etc. But I'm groping around for a = simple, clear recommendation for what we should tell people to do so = they can: a) Make their router work very well, with minimal latency b) Spend their time more usefully than tweaking QoS/priority = settings (for example, by actually playing the game that whose lag = you're trying to minimize :-) Many thanks! Rich On Dec 29, 2013, at 2:24 AM, Dave Taht wrote: >> QUESTION #4: What are the major features of (and/or differences = between) the simple.qos, simplest.qos, and drr.qos scripts? >=20 > Simplest.qos is the simplest possible htb based shaper, with only a > single fq_codel qdisc (with 1024 queues) Advantages are that it does > optimal mixing and uses the least memory. (it works pretty good down > to about 16 queues actually) >=20 > Simple.qos is a three tier system that can use diffserv and simple > prioritization to give or remove priority to certain kinds of > identifiable flows. Right now it gives priority to locally generated > dns and ntp packets, and a couple diffserv markings, and deprioritizes > CS1. It would be nice if it was feature-competitive with qos-scripts, > which have (for example) l7 inspection to find common torrent-like > protocols, and a gui with lots of knobs to control that aspect. >=20 > I waffle on calling things "tiers" rather than "queues". "levels?" > "Bands?" Band is used in the pfifo_fast and prio qdiscs, maybe we > should call it that. A queue can be a queue, but an fq_codel queue > consists of up to 64k flows which can also be considered queues. And > it's turtles all the way down. > ... Dave notes that inclusion of ddr.qos was a build error... --Apple-Mail=_A577639C-B154-4CD1-BAD1-A3B8FE688F8C Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQEcBAEBCgAGBQJVJvCOAAoJEH4agC/0z73/SRYIAIaRuntd83EhLsRVvmzuwWao 4x1sx/kj88vOFhdKhmpckhD8tzify7xsmsqJkVBFylFMaYH9MZVZkdX0qpPuI9qF lCjVSpe1i5yP9C24E6Y8Lybi09EbLT/cf/RRpvQc8qBjGeqwpTTr9a3nTXefbXJs rQaNbALM2sOvJVs0N33R6pL0THKD10l8I6ypOUO1bKDNfzjr70R/9tASLO+IL/W1 RquZKEwCmCyFsiii0eefg5jJeCX2f4EaL97Q2fUGDjqFO+VdNxqw2S1+2O1M+1oS oJMgBxorMLr6QBne3HCaQ5dPL5dmJlVac8kyUY9tZFbH0qo+WI03w/J5FFkWD8U= =jxFJ -----END PGP SIGNATURE----- --Apple-Mail=_A577639C-B154-4CD1-BAD1-A3B8FE688F8C--