Optical or Electrical Interconnects: Quantitative Comparison from Parallel Computing Performance View

Abstract

This paper considers the comparison between optical and electrical interconnect system from a parallel computing performance view. The motivation of the work is based on increasing demand on parallel computing tasks and the rapid development of optical chip-to-chip interconnects techniques. To meet the increasing demand of large-scale parallel or multiprocessor computing tasks, an analytic method to evaluate the computing performance of interconnect systems is proposed in this paper. The bandwidth-limit model and full-bandwidth model are both under our investigation. The paper characterizes the influence of unit processing time, communication overhead, processor number and the transmission time. The speedup and efficiency are selected to represent the parallel performance of an interconnect system. The analytic expressions of these two indexes are derived in the paper. Deploying the proposed models, we depict the performance gap between the optical and electrical interconnect systems. Results show that the large communication bandwidth optical chip-to-chip system has an obvious speedup gain, which is up to 93%. However, the existence of efficiency peak point indicates that the immoderate pursuing of high-bandwidth have no use for system efficiency improvement.