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.However, like you, I just sigh when I see the behemoth detnet is building.
Certainly, all you said is valid - as I stated, I mostly wanted to share the digest/the existance of the inititiative without judging/reproaching/peaching ...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.
Well, if it's already for specific HW, then I'd prefer to see RDMA in place right away with getting rid of IRQs and other TCP/IP specific rust along the way, at least for DC realms :) Although, this HULL might has a spin for it from economics perspective.I prefer the direction that Mohamad Alizadeh's HULL pointed in:
Less is More: Trading a little Bandwidth for Ultra-Low Latency in the Data Center
In HULL you have i) a virtual queue that models what the queue would be if the link were slightly slower, then marks with ECN based on that. ii) a much more well-behaved TCP (HULL uses DCTCP with hardware pacing in the NICs).
I would love to be able to demonstrate that HULL can achieve the same extremely low latency and loss targets as detnet, but with a fraction of the complexity.
For public Internet, not just for DCs? You might have seen the work we've done (L4S) to get queuing delay over regular public Internet and broadband down to about mean 500us; 90%-ile 1ms, by making DCTCP deployable alongside existing Internet traffic (unlike HULL, pacing at the source is in Linux, not hardware). My personal roadmap for that is to introduce virtual queues at some future stage, to get down to the sort of delays that detnet wants, but over the public Internet with just FIFOs.Thanks for sharing, that sounds thrilling - especially the achieved latencies and the non-spec. HW needs. All the best with it, again, maybe more an economical quarrel to overcome then again.
-- Besten Gruß Matthias Tafelmeier