From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (mail.toke.dk [IPv6:2a0c:4d80:42:2001::664]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 22D0A3B2A4; Fri, 9 Jul 2021 19:37:22 -0400 (EDT) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1625873838; bh=hD53ZZX4RMQeMQTMoVcHvmlXochqpRPdC0IOq+IH33Q=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=HtDKcGOoyfz2un//+OdaJ5FJUoUMESdaxJZjGkHZg1Qvfmxr1S5GBm+cKdP2kDbEo H/d6oA4UwlyuEhdXifJGnIbZrkBxYbwY4+Pthy4LzUvLUVaSTxAxE40zVWhA3VW7jz INr+/qjQmtnUkpgFHiwyaxu6C2+C8GaEHE20Y0xcBZKteckkV6FdBvo1bGikYNzsuB +EVDpwVwX3mzlAzic47XeQd0Y8iIDNTYGYf5cmXwujcmARbuHGHHHoy7KOBrkPBVXn pMrxFz8K6wmBt9Sc0Oq/3mtlZej5DASF62fbvnv6uY5VXdAo1Et84IuCLlLfXSvumP HVjHoRFnV6UOA== To: "Holland, Jake" , "David P. Reed" , Luca Muscariello Cc: "starlink@lists.bufferbloat.net" , Make-Wifi-fast , Leonard Kleinrock , Bob McMahon , Cake List , "codel@lists.bufferbloat.net" , cerowrt-devel , bloat , Ben Greear In-Reply-To: References: <1625188609.32718319@apps.rackspace.com> <989de0c1-e06c-cda9-ebe6-1f33df8a4c24@candelatech.com> <1625773080.94974089@apps.rackspace.com> <1625859083.09751240@apps.rackspace.com> Date: Sat, 10 Jul 2021 01:37:16 +0200 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87a6mvdpoz.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Codel] [Bloat] Little's Law mea culpa, but not invalidating my main point X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Jul 2021 23:37:22 -0000 "Holland, Jake via Bloat" writes: > Hi David, > > That=E2=80=99s an interesting point, and I think you=E2=80=99re right tha= t packet > arrival is poorly modeled as a Poisson process, because in practice > packet transmissions are very rarely unrelated to other packet > transmissions. > > But now you=E2=80=99ve got me wondering what the right approach is. Do you > have any advice for how to improve this kind of modeling? I actually tried my hand at finding something better for my master's thesis and came across something called a Markov-Modulated Poisson Process (MMPP/D/1 queue)[0]. It looked promising, but unfortunately I failed to make it produce any useful predictions. Most likely this was as much a result of my own failings as a queueing theorist as it was the fault of the model (I was in way over my head by the time I got to that model); so I figured I'd mention it here in case anyone more qualified would have any opinion on it. I did manage to get the Linux kernel to produce queueing behaviour that resembled that of a standard M/M/1 queue (if you squint a bit); all you have to do is to use a traffic generator that emits packets with the distribution the model assumes... :) The full thesis is still available[1] for the perusal of morbidly curious. -Toke [0] https://www.sciencedirect.com/science/article/abs/pii/016653169390035S [1] https://rucforsk.ruc.dk/ws/files/57613884/thesis-final.pdf