[Bloat] Tuning fq_codel: are there more best practices for slow connections? (<1mbit)

[cloneman <bufferbloat@flamingpc.com>]

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I'm trying to gather advice for people stuck on older connections. It
appears that having dedictated /micromanged tc classes greatly outperforms
the "no knobs" fq_codel approach for connections with  slow upload speed.

When running a single file upload @350kbps , I've observed the competing
ICMP traffic quickly begin to drop (fq_codel) or be delayed considerably (
under sfq). From reading the tuning best practices page is not optimized
for this scenario. (<2.5mbps)
(
https://www.bufferbloat.net/projects/codel/wiki/Best_practices_for_benchmarking_Codel_and_FQ_Codel/
) fq_codel

Of particular concern is that a no-knobs SFQ works better for me than an
untuned codel ( more delay but much less loss for small flows). People just
flipping the fq_codel button on their router at these low speeds could be
doing themselves a disservice.

I've toyed with increasing the target and this does solve the excessive
drops. I haven't played with limit and quantum all that much.

My go-to solution for this would be different classes, a.k.a. traditional
QoS. But ,  wouldn't it be possible to tune fq_codel punish the large flows
'properly' for this very low bandwidth scenario? Surely <1kb ICMP packets
can squeeze through properly without being dropped if there is 350kbps
available, if the competing flow is managed correctly.

I could create a class filter by packet length, thereby moving ICMP/VoIP to
its own tc class, but  this goes against "no knobs" it seems like I'm
re-inventing the wheel of fair queuing - shouldn't the smallest flows never
be delayed/dropped automatically?

Lowering Quantum below 1500 is confusing, serving a fractional packet in a
time interval?

Is there real value in tuning fq_codel for these connections or should
people migrate to something else like nfq_codel?

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