Hal Murray <hmur...@megapathdsl.net> writes: > Toke said: >> Yeah, the overhead of CoDel itself (and even FQ-CoDel) is basically nil (as >> in, we have not been able to measure it), when otherwise doing forwarding >> using the regular Linux stack. > > I may be able to help with that. > > Are you familiar with Dick Sites' KUtrace? > Stanford Seminar - KUtrace 2020 > https://www.youtube.com/watch?v=2HE7tSZGna0
Nope - but from a quick glance it looks similar to what you can do with 'perf'? :) > The catch is that I've never used CoDel so somebody will have to teach > me how to setup a test environment, and then show me the chunks in the > kernel you want to measure. To measure the CoDel algorithm, I guess the thing to measure would be codel_dequeue(): https://elixir.bootlin.com/linux/latest/source/include/net/codel_impl.h#L142 However, that has loops in it that depend on flow state, so its execution time will vary some. For fq_codel it would be the fq_codel_enqueue() and fq_codel_dequeue() functions, but they have a similar problem: https://elixir.bootlin.com/linux/latest/source/net/sched/sch_fq_codel.c Also, the larger problem is that the overhead of these drown in all the other processing the kernel does for each packet (none of the queueing-related functions even register on a 'perf' report when forwarding packets. Still, might be interesting to see, who knows? So feel free to take a stab at it :) -Toke _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat