Best performance delivery in heterogeneous computing unit environment

An apparatus for selecting an efficient processor includes a comparison module that compares performance characteristics of a plurality of processors available for execution of a function, where each performance characteristic varies as a function of function size. The apparatus includes a selection module that selects, based on a size of the function, a processor from the plurality of processors with a best performance for execution of the function, and an execution module that executes the function on the selected processor.