1. In a data processing system having multiple processing nodes exhibiting low access latency to a system memory construct, a method for efficient dispatch/completion of a work element, said method comprising: a runtime scheduler selectively allocating the work element to specific processing nodes or processing units from among the multiple processing nodes to complete execution of a work element that has multiple individual work items that may be independently executed by different ones of the multiple processing nodes and by different ones of the processing units; generating an allocated processor unit (APU) bit mask that identifies at least one of the processing nodes or processing units that has been selected; placing the work element in a first entry of a global command queue (GCQ); associating the APU mask with the work element in the first entry of the GCQ; and responsive to receipt at the GCQ of work requests from each of the multiple processing nodes or the processing units, dispatching work items from the work element in the GCQ to only the selected specific processing nodes or the processing units.