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?