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