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