However, like you, I just sigh when I see the behemoth detnet is building.

Does it? Well, so far the circumference seems justififiable for what they want
to achieve, at least according to what I can tell from these rather still
abstract concepts.

            The sort of industrial control applications that detnet is targeting
        require far lower queuing delay and jitter than fq_CoDel can give. They
        have thrown around numbers like 250us jitter and 1E-9 to 1E-12 packet
        loss probability.

    Nonetheless, it's important to have a debate about where to go to next.
    Personally I don't think fq_CoDel alone has legs to get (that) much better. 

The place where bob and I always disconnect is that I care about
interflow latencies generally more than queuing latencies and prefer to
have strong incentives for non-queue building flows in the first
place. This results in solid latencies of 1/flows at your bandwidth. At
100Mbit, a single 1500 byte packet takes 130us to deliver, gbit, 13us,
10Gbit, 1.3us.

A not necessarily informed enough question to that: couldn't this marking based virtual queueuing get extended to a per flow mechanism if the marking loop was implemented in an efficient way?

-- 
Besten Gruß

Matthias Tafelmeier