NCPA : energy-efficient voltage scaling algorithm for multiprocessor embedded system

Abstract

As the number of processors in a chip increases, the power consumption of processors became a primary concern in embedded system design. The voltage scaling method is widely recognized as a means of reducing power consumption of the processor and it has been studied throughout many researches. In multiprocessor environment, there are two types of time-slacks which can be utilized by voltage scaling. The first type of timeslack is caused by the dependency among multiple tasks running on different processors. The second type of slack comes from the variation of execution cycles of the task. In this paper, we propose the novel intra-task voltage scaling method called n-th critical path algorithm(NCPA) which can utilize both types of time-slacks by adopting on-line approach which determines the performance level of the processor at run-time with minimal overhead. Our experiment shows that proposed algorithm achieves 28% of energy reduction over conventional method when applied to a commercial multimedia application.