[Cake] Multiple Hardware Queues

[Dave Taht]

I note that I like the idea of cake-mq (or rather, cake-smp). If we
can currently achieve 50gbit bottlenecking on one cpu, what can be
done to get past 100gbit?

tc qdisc add dev eth root cake-smp bandwidth 100gbit

has a nice ring to it don't you think? :)

* BQL's estimator is essentially additive. If you have 64 hw queues
(common in 10gige hw), you've got a ton of inessential latency that
builds up there due to bulking.

* I have grave doubts about 64k aqm'd queues at any speed. Better to
have less queues.

* In a naive parallel implementation (and excluding some painful
implementation details) - only the global shaped bandwidth limit has a
need for atomic, cross cpu access, and even that can essentially be
rcu'd.