[Cerowrt-devel] SQM in mainline openwrt, fq_codel considered for fedora default

[Dave Taht]

> http://snapon.lab.bufferbloat.net/~d/beagle_bql/bql_makes_a_difference.png
>
> You can see that BQL makes the most difference in the latency.

And ALSO that these fixes also improved system throughput enormously.
This is partially due to the improvement in ack clocking you get from
reduced RTTs, partially due to improved cache behavior (shorter
queues), and partially continual improvements elsewhere in the tcp
portions of the stack.

With more recent kernels...

I now get full throughput from the beagles in both directions with the
3.16 kernel,
the stil out of tree bql patch, and either fq or fq_codel. I haven't
got around to plotting all those results (they are from kathie's new
lab), but they are here:
http://snapon.lab.bufferbloat.net/~d/pollere/

There is a small buffered tail dropping switch in the way, on these
later data sets. There was some puzzling behavior on the e1000e that I
need to poke into in a more controlled setting.

As for other tunables on hosts, TCP small queues might be amiable to
some tuning, but that too may well evolve further in kernelspace.

-- 
Dave Täht

http://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks