[Codel] [PATCH net-next] codel: use Newton method instead of sqrt() and divides

[dave taht]

I am sitting here with the latest fq_codel implementation on cerowrt, and
this new 16 bit change.

With either interface, running netserver on the router, I get 
~260Mbit/sec out of it,
with fq_codel on. It's quite marvelous, as ping times stay in the 2-3ms 
range...

Running traffic through the router with two fq_codels is another story.

I get only 91.6Mbit out of it (and the cpu on the router is loafing). I 
was rather puzzled as
this is sooclose to 100Mbit as for me to assume that I had goofed and 
was running
at line rate, but no, I'm at gigE on both sides.

A) Scheduler granularity? HZ_256 and NO_HZ here. Not sure of the clock res
B) The new error in the new sqrt routine actually significant enough to 
show up

I will try a 20ms target and revert to the previous fuller precision 
version. I wish I had data on the previous version but was battling an 
entirely different bug, then.

Has anyone hooked up a chain of codel ns3 sims to each other?

Or a few gigE boxes through each other?

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