[Cake] cake flenter results round 4

Dave Taht dave at taht.net
Sun Dec 3 22:29:11 EST 2017


Pete Heist <peteheist at gmail.com> writes:

> http://www.drhleny.cz/bufferbloat/cake/round4/
>
> Round 4 Tarball: http://www.drhleny.cz/bufferbloat/cake/round4.tgz
>
> *** Notes/Analysis ***
>
> * I took the average satellite Internet latency of 638ms
> (https://en.wikipedia.org/wiki/Satellite_Internet_access) and tried 20/20mbit
> 320ms delay each direction. So here we have 20mbit symmetric Internet with Cake
> running on both the CPE and satellite- common config! I’m sorry we don’t have
> Tooway 6/22mbit anymore for a real test, which was also here in desperation at
> the house at some point.
>
> * Since I left the default rtt setting for most tests, these tests are an
> exploration of what problems that can cause. I enjoy failed experiments though
> (I’m looking at you penicillin). Here we can see that as we increase Cake’s rtt
> setting, total bandwidth improves, generally:
>
> http://www.drhleny.cz/bufferbloat/cake/round4/cake_rtt_200ms_rrulbe_eg_cake_18.0mbit/index.html (22.77mbit)
> http://www.drhleny.cz/bufferbloat/cake/round4/cake_rtt_400ms_rrulbe_eg_cake_18.0mbit/index.html (26.17mbit)
> http://www.drhleny.cz/bufferbloat/cake/round4/cake_rtt_600ms_rrulbe_eg_cake_18.0mbit/index.html (25.99mbit)
> http://www.drhleny.cz/bufferbloat/cake/round4/cake_rtt_800ms_rrulbe_eg_cake_18.0mbit/index.html (25.96mbit)
> http://www.drhleny.cz/bufferbloat/cake/round4/cake_rtt_1000ms_rrulbe_eg_cake_18.0mbit/index.html (29.04mbit)
>
> * Cool. In this case, increasing rtt actually _improves_ host fairness, as
> opposed to what we see with Ethernet around rtt 1ms, although TCP RTT suffers:

Hmm.

>
> http://www.drhleny.cz/bufferbloat/cake/round4/hostiso_cake_200ms_eg_cake_src_cake_dst_18.0mbit/index.html (1.83)
> http://www.drhleny.cz/bufferbloat/cake/round4/hostiso_cake_400ms_eg_cake_src_cake_dst_18.0mbit/index.html (1.64)
> http://www.drhleny.cz/bufferbloat/cake/round4/hostiso_cake_600ms_eg_cake_src_cake_dst_18.0mbit/index.html (1.57)
> http://www.drhleny.cz/bufferbloat/cake/round4/hostiso_cake_800ms_eg_cake_src_cake_dst_18.0mbit/index.html (1.45)
> http://www.drhleny.cz/bufferbloat/cake/round4/hostiso_cake_1000ms_eg_cake_src_cake_dst_18.0mbit/index.html (1.06)
>
> * Sorry for the delay and not testing much in the last few days. R.I.P. our 16yo
> European housecat who left us yesterday. I really liked that cat. I’ve enjoyed
> looking at some of George’s results meanwhile...

:(

I used to have a cat, 'cindi clawford'. Been travelling too much to ever
settle down again, it seems.

>
> *** Round 5 Plans
>
> * If I do another high RTT test, make rtt 1000ms default and try even higher
>
> * From Dave: tcp bbr, cdg, reno? dctcp would be weirdly interesting.
>
> * From Dave: slot 4ms 4ms bytes 10k 16
>
> * If I get time I could change flenter to do asymmetric bandwidth tests and go
> back to Dave’s four box config with ingress cake, which would probably be a more
> common config. All depends on time available…

Well, let's see what happens on netdev.

I took a few steps towards ripping out blue for comparison the other
day.

>
>
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