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