From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vx0-f171.google.com (mail-vx0-f171.google.com [209.85.220.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 3C0D9200B10 for ; Wed, 4 Jan 2012 07:25:52 -0800 (PST) Received: by vcbfl11 with SMTP id fl11so22317693vcb.16 for ; Wed, 04 Jan 2012 07:25:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=sender:message-id:date:from:organization:user-agent:mime-version:to :cc:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=rTLEbm7eBPO1Sm1YkRCy4hGAJtvbJGItZO7XIK+tjl8=; b=JFdooZX3zejMPip2P1pU4j+hZpBxKPYhOmKBbfrcdLk/fZLKqCbgdMV5Rn4vK6uX4B KcgnyAs7sZXW2DI25UFxVVQFxtfSfVSN3P7htXI3pN2DTkmApxdrPulz3fErqVqcCI1m NadbbYPV+KeV4i0559Zpu1uDVYd40HFB/PUIU= Received: by 10.220.107.79 with SMTP id a15mr32057722vcp.61.1325690750408; Wed, 04 Jan 2012 07:25:50 -0800 (PST) Received: from [192.168.1.5] (c-24-63-191-17.hsd1.ma.comcast.net. [24.63.191.17]) by mx.google.com with ESMTPS id g6sm23326738vdf.15.2012.01.04.07.25.48 (version=SSLv3 cipher=OTHER); Wed, 04 Jan 2012 07:25:49 -0800 (PST) Sender: Jim Gettys Message-ID: <4F046F7B.6030905@freedesktop.org> Date: Wed, 04 Jan 2012 10:25:47 -0500 From: Jim Gettys Organization: Bell Labs User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111124 Thunderbird/8.0 MIME-Version: 1.0 To: Dave Taht References: <1325481751.2526.23.camel@edumazet-laptop> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: bloat Subject: [Bloat] What is fairness, anyway? was: Re: finally... winning on wired! X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Jan 2012 15:25:53 -0000 On 01/02/2012 04:31 PM, Dave Taht wrote: > On Mon, Jan 2, 2012 at 9:07 AM, Dave Taht wrote: > Yes, that patch brings SFQ at light workloads to being > indistinguishable from QFQ! > http://www.teklibre.com/~d/bloat/sfqnewvsqfq10iperfs.png (if you stare > at this image long enough you might see a pattern, but I don't) (I > certainly am seeing an afterimage, though) >>> A "nolimit" implementation could use a dynamic memory allocator >>> scheme, eventually consuming less memory on typical use :) > At what point could SFQ be considered a replacement for pfifo_fast? :) > > I have not managed to crash QFQ yet with your other new patch. I will > run it overnight. > > As I read this thread, there are three questions that go through my mind: 1) since TCP is not "fair", particularly when given flows of different RTT's, how do we best deal with this issue? Do either/both SFQ/QFQ deal with this problem, and how do they differ? 2) Web browsers are doing "unfair" things at the moment (unless/until HTTP/1.1 pipelining and/or SPDY deploys), by opening many TCP connections at the same time. So it's easy for there to be a bunch of flows by the same user. Is "fairness" better a per host property in the home environment, or a per TCP flow? Particularly if we someday start diffserv marking traffic, I suspect per host is more "fair", at least for unmarked traffic. 3) since game manufacturers have noted the diffserv marking in PFIFO-FAST, what do these queuing disciplines currently do? - Jim