From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.tohojo.dk (mail.tohojo.dk [188.40.53.186]) (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 4424221F199; Fri, 23 Nov 2012 02:39:38 -0800 (PST) Received: from alrua-laptop.borgediget.toke.dk (1809ds4-ro.0.fullrate.dk [90.184.46.60]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.tohojo.dk (Postfix) with ESMTPSA id 229A21EC0540; Fri, 23 Nov 2012 11:39:35 +0100 (CET) Received: by alrua-laptop.borgediget.toke.dk (Postfix, from userid 1000) id 3427592A; Fri, 23 Nov 2012 11:39:34 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Dave Taht In-Reply-To: (Dave Taht's message of "Fri, 23 Nov 2012 06:53:16 +0100") Date: Fri, 23 Nov 2012 10:50:20 +0100 References: User-Agent: Gnus/5.130006 (Ma Gnus v0.6) Emacs/24.2 (gnu/linux) Message-ID: <87mwy8a9i4.fsf@toke.dk> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" X-Mailman-Approved-At: Mon, 26 Nov 2012 16:52:30 -0800 Cc: codel@lists.bufferbloat.net, David Woodhouse , cerowrt-devel@lists.bufferbloat.net, bloat Subject: Re: [Bloat] plots 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: Fri, 23 Nov 2012 10:39:38 -0000 --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Dave Taht writes: > The *.svg of high bandwidths is nice, the *.ps of low is not so much. Yeah, I see your point. > 1) I think the way to fix the upload plot is to use a larger sample > interval, like 1 second, when dealing with low bandwidths. Well, the reason for missing data is that netperf "misses its deadlines" so to speak. I.e. we tell it to output intermediate results every 0.1 seconds, and it only does so every 0.5. As I understood Rick's explanation of how netperf's demo mode works, the problem with missing deadlines is that netperf basically tries to guess how much data it will send in the requested interval, and then after having sent that much data it checks the time to see if it's time to output an intermediate result. So if the data transfer rate is slower than expected, the deadline will be missed. Using negative numbers for the interval makes it check the time every time it sends something, but it still needs to send a bit of data between every check, and if that takes too long the holes will appear. Using a longer sampling interval for the entire plot might alleviate this, I suppose, but since we're measuring bytes sent per second, doing so amounts to averaging subsequent points; so is there any reason why we can't just do the averaging over the data we already have (i.e. just increase the interpolation interval)? If we do want to increase the actual sampling interval, do you propose to do so only for low-bandwidth tests? Because in this case we would either need to detect when the bandwidth is low and adjust parameters, or there would have to be two versions of the test: a low-bandwith and a high-bandwith version. > 2) I am really hating losing the outliers entirely. In particular, > > Getting a second ping plot that used a cdf would be more accurate and > revealing. I agree that this is not optimal, and I've been thinking that I would like to decouple the data gathering part from the plotting part a bit. I.e. making it possible to specify a test that gathers a lot of data (could add in tc stats for instance) and saves it, and then specify several sets of plots to do on that data. CDF would be one of them, another one could be a simpler plot that plots the average (or total) upload and download with just the ping, similar to the simple plots we did with just two streams. And I'm sure we can come up with more. Export would still be there, of course; in fact, I was planning to switch to using json as the native storage format. I still have a way to go on my project writing before I get to doing the tests for myself, but I can try and interleave some work on netperf-wrapper to get the above changes in there? :) =2DToke =2D-=20 Toke H=C3=B8iland-J=C3=B8rgensen toke@toke.dk --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQEcBAEBCAAGBQJQr1JjAAoJEENeEGz1+utP688H/jhdA7srvX3rLVMYJQxedKfm njLcyu+NMBbTeuOP/kM2Fmby+TcILupd9GdQ3DxpBMSre+V7B6jIJjSOYlqN92lu +SjqVIQHhwYJTt2ILXWFi7s88oi8u0WaxlaphDefSl3Ipu4x3klVq4i1YXVCrHUP z55zSUUGAys9wkLuNsS0wiYdNuHWCoyml8qAIddil/3ApWzyd0LxUhNrXA9mluFc YLxNn8rxDroJwB1FwrqAPVwwYAXKCQMTLeXop9qOjT6kQl3HdswhREdgw3o1D0Og vDP3F6aUJcOeHIXaPnVmW188k2Ag0fUsa+dV0RDKpjb+WK5CJrG3sY+lf4jNwcQ= =q3dk -----END PGP SIGNATURE----- --=-=-=--