From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nm26.access.bullet.mail.sp2.yahoo.com (nm26.access.bullet.mail.sp2.yahoo.com [98.139.44.153]) (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 6340121F129 for ; Mon, 6 May 2013 12:45:02 -0700 (PDT) Received: from [98.139.44.107] by nm26.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 May 2013 19:45:01 -0000 Received: from [67.195.22.107] by tm12.access.bullet.mail.sp2.yahoo.com with NNFMP; 06 May 2013 19:45:01 -0000 Received: from [127.0.0.1] by smtp103.rog.mail.gq1.yahoo.com with NNFMP; 06 May 2013 19:45:01 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rogers.com; s=s1024; t=1367869501; bh=IBkfgOonIKqjMd8gNykI0J+v2XxlwUN0N2CnrBvHTsM=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Message-ID:Date:From:Reply-To:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=ZAMEAyzNyNKQ9wKbzrp4Fp0W5KNRjltjDkX+HFrRuLXDPElbJ5KEFsudonsse20FnojtZ2HFP2sJyUb0fSWxFxwIQ4o3SC1Rk36+LVtwGAh5GmAVHVqDZuH+J1KjFhEbov/aNq1XqJ09frGjwmeuPhxgxo8ybSQqg5hmZcZg5Uo= X-Yahoo-Newman-Id: 905242.12189.bm@smtp103.rog.mail.gq1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 5kiX05MVM1l6jb85T06Lv29njFr0W15F3h_7059gpIbwRiB mvk4P2.RdTN1TerdBkRPQXeZ5eUsfTwb46In5TY6ZJDOt1fE9lDY.d7GRhkp KkPM7gSVFzf8l8qVnVrbOJX6X8Niklnoq6OeoHQ9jai0O.wJGfn9mumPFqti _.kqgED7tm3T4hfvU_7a3wuW0dqwiRM8_7iJk10rRntuSAxKOr1k_4TZQP01 F8PYBrETqucmfRNV6AfaDFsitdh2uFcONbMO38q2hlX_Tww8XaYUfvTrEqRh NlHKyFetOHJHEyV3c0JAf99Ky.GIja41oIXpHK6KOJihYNwi405VFVB_cXvJ izo2XMqJf00zyfxEB7B5zMJ8XNc_m2J6FpX5unzYChlfBxPMTIbjFA4uRJmf IDl2YJbN6uBCX7UzLXOu_ttHQGDXFV8IjtQXiZWNgbbhShFrMGWLfVhW_YMK GrdBCywGOVGCGM5YG2dEm9WByUjE- X-Yahoo-SMTP: sltvjZWswBCRD.ElTuB1l9j6s9wRYPpuyTNWOE5oEg-- X-Rocket-Received: from [192.168.1.103] (davec-b@99.225.204.110 with plain) by smtp103.rog.mail.gq1.yahoo.com with SMTP; 06 May 2013 12:45:01 -0700 PDT Message-ID: <5188096F.20804@rogers.com> Date: Mon, 06 May 2013 15:50:07 -0400 From: David Collier-Brown User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: bloat@lists.bufferbloat.net References: In-Reply-To: X-Enigmail-Version: 1.5.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] Bloat Digest, Vol 29, Issue 6 X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list Reply-To: davecb@spamcop.net List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 06 May 2013 19:45:02 -0000 Oliver Hohlfeld wrote: >> In ascii art, it might look like this: >> ======++++++++++++ >> - + >> - + >> - + >> - + > What exactly does this plot represent and on what measurement > data is it based on? What is your definition of "good" and "bad"? > Just response times? Where does it's shape comes from? > > Before (again) diving into debates on how bufferbloat marketing plots > should look like, I think we need to make sure that the marketing > is backed up by empirical data. > > --Oliver It's the inverse of a response time versus load graph for two cases, one with a very early degradation, the other with a normal one. It's a bowdlerized version of some real measurements of a REST-based system with and without a bug. I see the list software put in a link to the gif, so look at that: it's far better than my hack at "art". Good and bad are indeed defined in terms of response time for a request-replay pair, with the appropriate units being part of my question. The normal shape of a response-time curve is a "hockey stick", like "_/". Technically it's a hyperbola with it's legs asymptotic to a pair of straight lines, one line horizontal at the value for load=1, and the second slanted at an angle that depends on the response time, the bottleneck time (if different), the think time between requests and the load. The right-side-up graph uses normal time units. I tried the experiment of inverting it and asking Dave and the list for an opinion on units: in my actual example they were normalized by dividing by the minimum response time, making it non-dimensional. --dave -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain (416) 223-8968