[Bloat] Difference between codel and fq_codel?

Toke Høiland-Jørgensen toke at toke.dk
Wed Feb 3 15:33:27 EST 2016


John Klimek <jklimek at gmail.com> writes:

> I'm currently using pfaense which only supports codel and not
> fq_codel. Is there a big difference between them? Is it worth looking
> into using a different router?

Yes, and quite possibly. :)

Basically, Codel drops packets to try to keep queues small. This works
reasonably well. However, what FQ-CoDel adds is flow isolation and
priority for sparse flows, which is what in most cases gets rid of
almost all of the added latency under load.

For a (much) longer version of the above, see this:
http://www.sciencedirect.com/science/article/pii/S1389128615002479 -- In
particular, figure 2 shows the performance of a bunch of different
algorithms, including CoDel and FQ-CoDel :)

-Toke


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