[Bloat] powerboost and sqm

[Pete Heist]

> On Jun 30, 2018, at 8:26 AM, Jonas Mårtensson <martensson.jonas at gmail.com> wrote:
> 
> I played around with flent a bit, here are some example plots:
> 
> https://dl.dropbox.com/s/facariwkp5x5dh1/flent.zip?dl=1 <https://dl.dropbox.com/s/facariwkp5x5dh1/flent.zip?dl=1>
> 
> The short spikes are not seen with flent so I'm led to believe these are just a result of running the "Hi-Res" dslreports test in a browser. In the flent rrul test, up to about 10 ms induced latency can be seen during the "powerboost" phase but after that it is almost zero. I'm curious about how this is implemented on the ISP side. If anything, sqm seems to induce a bit more latency during the "steady-state" phase.

You may also want to try running flent with --socket-stats and making a tcp_rtt plot. You should see a significant difference in TCP RTT between sfq and anything that uses CoDel.

Also, double check the basics- that you’re truly in control of the queue and the device running sqm isn’t running out of CPU and has solid device drivers that aren’t causing periodic pauses or other anomalies (which also follows for your client device). I’ve been sideswiped by such things before when testing sqm, and making theory and experiment fully agree can take science and time.

Pete

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