[Codel] cake status ( was Codel's count variable and re-entering dropping state at small time intervals)

[Dave Taht]

I would like to stress that cake is a work in progress, taking place
with very limited resources - jonathon's funding ran out last month
and we've had to scramble to keep a floor under him F/T, toke is
contributing his testbed and test scripts that he used for "The good
the bad and the wifi", recently published in computer networks:
https://kau.toke.dk/experiments/good-bad-wifi/ so we can compare all
prior qdiscs...

but he is otherwise on vacation... various other parties have
contributed scripts to use it in openwrt... and I am entirely unpaid,
yet contributing a few servers and clients in real world scenarios
while working primarily on the make-wifi-fast stuff, for which some of
cake's algorithms may apply but the code needs to move to the
mac80211e layer, which was discussed at battlemesh.

Other bits - like the new more robust linux hashing api which supports
macaddr and mpls targets - are in rapid development elsewhere and we
are not tracking that work well.

Any suggestions towards putting a better floor under this increasingly
promising work are welcomed. Any grant money out there?

Exploration of various constants, ratios, and other bits of math
throughout the code is welcomed, also. All the code is open source and
easily buildable for many versions of linux now. Feel free to play.

Much needed are testing and analysis at both line and shaped rates at
1gigE, 10gige and higher, (anyone got 10GigE in a testbed we can use?)
-

testing at longer rtts is needed (we probably need to expose the
interval parameter for the satcomm folk), and with more mixtures of
traffic than we currently use. We  worked out how to test webrtc only
recently (at ietf), for example, but not coded it up.

ns2 and ns3 models are needed.

there are some thoughts towards leveraging qfq in another group of
researchers, more news on that as it happens.

Lastly, if anyone knows of some cites for previous attempts at deficit
mode schedulers and the other key ideas in cake - we have not done an
exaustive liturature search yet, for that pentultimate paper that is
in progress.

Having a ton of fun though! "What we did on our summer vacation!"