[nvarsj]

You need buffers to maintain high bandwidth. There is no way around that. The problem is lack of AQM in end user routers - where a single high bandwidth flow can fill up and hog those buffers, disrupting latency sensitive flows. We're slowly seeing some adoption of things like fq_codel, but it's not perfect since the user has to go and manually enter their upload/download speeds (which again are not easy to determine, especially for ISPs with "boost" limiting). Ideally home routers would dynamically adjust based on observed latencies.

[tialaramex]

Codel is knobless, there literally aren't parameters you _can_ set let alone ones you need to set according to your "upload/download speeds". So, I have no idea what you're tinkering with that you think needs to know "upload/download speeds" or why, but it's nothing to do with Codel.

[nvarsj]

fq_codel alone doesn't solve buffer bloat. There are still huge buffers upstream. You need to combine it with local rate limiting so you can control the buffer in your local home router. fq_codel/cake work by looking at time a packet spent in a local queue. If you don't rate limit locally, then your local queue is always empty and everything queues upstream. Modern routers with things like "Dynamic QOS" that use fq_codel all require providing downstream/upstream values. This is way simpler than more traditional qos, but it's still a barrier to wide spread adoption.