Enable Adaptative RED algo, using :

tc qdisc  ... red limit BYTES ... adaptative ...

Support of high precision probability/max_p setting and reporting, with
support of old kernels.

With a new kernel, "Plog ..." is replaced in tc output by "probability
value" :

qdisc red 10: dev eth3 parent 1:1 limit 360Kb min 30Kb max 90Kb ecn ewma
5 probability 0.09 Scell_log 15