Is this classic buffer bloat on 50 megabit cable modem? https://www.dslreports.com/forum/r31035315-Weird-speed-test-results-It-falls-off-right-at-the-end
by extending the download duration to 30 seconds, what looks like a speed "fall-off at the end" reveals two complete stall/recoveries, and associated high latency during the download phase. On Thu, Oct 13, 2016 at 2:22 PM, Dave Taht <dave.t...@gmail.com> wrote: > Thank you very much for the explanation and the fix. I am confronted > by the dsltestreports stuff every day on my search for bufferbloat. I > don't consider it annoying, but as a chance to spot check! > > ... > > I still might quibble, but a trimmed mean makes more sense than just a > mean. > > Problem I always have is bloat is biased always towards the end of a test. > Here, > at 1gbit, it took nearly 20 seconds to start going boom. Maybe we need > to invent a new distribution (The bloat distribution? The TCP > distribution)... > > You are getting towards a big dataset now. (has it been a year yet?) > Got anyone lined up for a paper on it? I'd still love it if one day > someone could take all the data you are filtering out, and plot > that.... > > I imagine the user's test result is cached and not subject to these > modifications? > > On Wed, Oct 12, 2016 at 5:57 PM, jb <jus...@dslr.net> wrote: > > It is done > > under the trimmed mean method, that would be a "C" grade result. > > > > > > > > On Thu, Oct 13, 2016 at 11:46 AM, jb <jus...@dslr.net> wrote: > >> > >> Actually I think the concept I need is the trimmed mean. > >> throwing away the highest couple of values (lowest couple are not to be > >> thrown away because they can't be errant). > >> It isn't perfect but it would help. > >> > >> On Thu, Oct 13, 2016 at 11:39 AM, jb <jus...@dslr.net> wrote: > >>> > >>> A while ago I changed from mean to median with the reasoning being that > >>> one spike to a crazy level was not representative of bloat but instead > >>> representative of a network stall or other anomaly. Graphs that were > nearly > >>> all good samples with one outlier were being unfairly graded poorly. > >>> > >>> But this example has the opposite issue - the median of this set of > >>> samples is the first half where everything is ok. Hence the good score. > >>> Using a mean would be correct for this sample. > >>> What should happen is to throw away a couple (max) outliers first, then > >>> do a mean to avoid punishing the results that come in as good but > include > >>> one errant measurement. > >>> > >>> thanks > >>> -Justin > >>> > >>> On Wed, Oct 12, 2016 at 11:16 PM, Dave Taht <dave.t...@gmail.com> > wrote: > >>>> > >>>> This has major bloat happening at the end of the upload test. Which > >>>> worries me - here, at a gbit. > >>>> > >>>> http://www.dslreports.com/speedtest/5284047 > >>>> > >>>> -- > >>>> Dave Täht > >>>> Let's go make home routers and wifi faster! With better software! > >>>> http://blog.cerowrt.org > >>>> _______________________________________________ > >>>> Bloat mailing list > >>>> Bloat@lists.bufferbloat.net > >>>> https://lists.bufferbloat.net/listinfo/bloat > >>> > >>> > >> > > > > > > -- > Dave Täht > Let's go make home routers and wifi faster! With better software! > http://blog.cerowrt.org >
_______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat