[Ecn-sane] duplicating the BBRv2 tests at iccrg in flent?

[Dave Taht <dave.taht@gmail.com>]

I see from the iccrg preso at 7 minutes 55 s in, that there is a test
described as:

20 BBRv2 flows
starting each 100ms, 1G, 1ms
Linux codel with ECN ce_threshold at 242us sojurn time.

I interpret this as

20 flows, starting 100ms apart
on a 1G link
with a 1ms transit time
and linux codel with ce_threshold 242us

0) This is iperf? There is no crypto?

1) "sojourn time" not as as setting the codel target to 242us?

I tend to mentally tie the concept of sojourn time to the target
variable, not ce_threshold

2) In our current SCE work we have repurposed ce_threshold to do sce
instead (to save on cpu and also to make it possible to fiddle without
making a userspace api change). Should we instead create a separate
sce_threshold option to allow for backward compatible usage?

3) Transit time on your typical 1G link is actually 13us for a big
packet, why 1ms?

is that 1ms from netem?

4) What is the topology here?

host -> qdisc -> wire -> host?

host -> qdisc -> wire -> router -> host?

5) What was the result with fq_codel instead?


-- 

Dave Täht
CTO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-831-205-9740