Starting at the queue and iteratively repeating at each scheduling level until reaching the root scheduler, each node in the scheduling hierarchy maintains {HEAD ~ an actual count} of {TAIL ~ tasks} corresponding to the node 
of
Starting at the queue and iteratively repeating at each scheduling level until reaching the root scheduler , each node in the scheduling hierarchy maintains { HEAD ~ an actual count } of { TAIL ~ tasks } corresponding to the node
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH