[Bloat] DSLReports Speed Test has latency measurement built-in

Dave Taht dave.taht at gmail.com
Sun Apr 19 15:22:09 EDT 2015


So my "acid test", taken on a linux box over ethernet, through a
cerowrt box with sqm-scripts turned off. This is my gf's comcast
"blast" service, which is rated for 55mbits down and 5.5mbits up. The
new speedtest does indeed show results that have the typical bloat
(nearly a second) a cable modem has when tested solely for up and
down, separately.

http://www.dslreports.com/speedtest/322800

A) I definitely am not particularly huge on defaulting to a log scale
for this graph. Or rather, I would be huge on the graph defaulting to
a linear scale AND huge when you get numbers as bad as this. :)

B) is there a way to specify ipv6?

2) So I did a follow on speedtest with fq_codel enabled to shape with
sqm. it may be that my upload shaper is a bit over what is desirable
for this link, and I need to repeat.

http://www.dslreports.com/speedtest/322992

3) For giggles, this one is with ecn enabled both on the shaper and on
the tcp I am using, showing that this speedtest site will use ecn when
enabled:

http://www.dslreports.com/speedtest/323101

Some ecn mark results on the shaper for that:

http://pastebin.com/sniePC1M

Both these tests are showing some latency spikes so it does look like
I should tune down the shaper a bit.

3) The rrul, rrul_be, tcp_upload, and tcp_download test data from
netperf-wrapper under both these circumstances (no ecn) is up at:

http://snapon.lab.bufferbloat.net/~d/lorna-ethernet.tgz

Feel free to create graphs and comparisons to suit selves.

A few graphs:
cdf plot of latency (have to use a log scale!!) compared between the
shaped and unshaped alternatives...

http://snapon.lab.bufferbloat.net/~d/lorna-ethernet/comcast_55_speedtest_comparison.png

what the overbuffered download looks like:

http://snapon.lab.bufferbloat.net/~d/lorna-ethernet/comcast_55_speedtest_comparison_download_bloated.png

The shaped fq_codeled equivalent:
http://snapon.lab.bufferbloat.net/~d/lorna-ethernet/comcast_55_speedtest_comparison_download_fq_codeled.png

(log scale comparison again - 10ms of induced latency vs 400+! Aggh)

And a graph of probably minimal usefulness comparing the behavior of
the shaped vs unshaped download flow configurations, for both ipv4 and
ipv6.

http://snapon.lab.bufferbloat.net/~d/lorna-ethernet/comcast_55_speedtest_comparison_download_compared.png

On Sun, Apr 19, 2015 at 10:43 AM, Dave Taht <dave.taht at gmail.com> wrote:
> I am going to do an acid test today. The line I tested last night is a
> comcast cable line (with htb+fq_codel on the link). So I plan to plug
> in the ethernet on both my mac and linux laptops and repeat the
> comparison with the shaper on and off, with both linux and osx.
>
> the *really funny* part of this is that I do not have a single extra
> ethernet cable in my gf's SF apartment, and the less funny part of
> this is the nearest radio shack is now closed....



-- 
Dave Täht
Open Networking needs **Open Source Hardware**

https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67



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