From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bifrost.lang.hm (mail.lang.hm [64.81.33.126]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 6CF2321F265 for ; Sun, 22 Mar 2015 18:45:54 -0700 (PDT) Received: from asgard.lang.hm (asgard.lang.hm [10.0.0.100]) by bifrost.lang.hm (8.13.4/8.13.4/Debian-3) with ESMTP id t2N1jpBu027097; Sun, 22 Mar 2015 17:45:51 -0800 Date: Sun, 22 Mar 2015 18:45:51 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Jonathan Morton In-Reply-To: <08BAF198-87C5-42B8-8899-53F34E47156E@gmail.com> Message-ID: References: <08BAF198-87C5-42B8-8899-53F34E47156E@gmail.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="680960-1711802326-1427075151=:22474" Cc: "cerowrt-devel@lists.bufferbloat.net" Subject: Re: [Cerowrt-devel] archer c7 v2, policing, hostapd, test openwrt build 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: Mon, 23 Mar 2015 01:46:23 -0000 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --680960-1711802326-1427075151=:22474 Content-Type: TEXT/PLAIN; charset=utf-8; format=flowed Content-Transfer-Encoding: 8BIT On Mon, 23 Mar 2015, Jonathan Morton wrote: >> On 23 Mar, 2015, at 02:24, Dave Taht wrote: >> >> I have long maintained it was possible to build a better fq_codel-like >> policer without doing htb rate shaping, ("bobbie"), and I am tempted >> to give it a go in the coming months. > > I have a hazy picture in my mind, now, of how it could be made to work. > > A policer doesn’t actually maintain a queue, but it is possible to calculate when the currently-arriving packet would be scheduled for sending if a shaped FIFO was present, in much the same way that cake actually performs such scheduling at the head of a real queue. The difference between that time and the current time is a virtual sojourn time which can be fed into the Codel algorithm. Then, when Codel says to drop a packet, you do so. > > Because there’s no queue management, timer interrupts nor flow segregation, the overhead should be significantly lower than an actual queue. And there’s a reasonable hope that involving Codel will give better results than either a brick-wall or a token bucket. are we running into performance issues with fq_codel? I thought all the problems were with HTB or ingress shaping. David Lang --680960-1711802326-1427075151=:22474--