AN ANALYTICAL APPROACH TO PERFORMANCE COST MODELING OF PARALLEL COMPUTERS

Although parallel processing has been a focal point of computer architecture research for many years, fundamental questions and trade-offs still remain puzzling, not necessarily because of complexity but because of the multitude of possible answers (e.g., shared vs distributed memory, centralized vs distributed control, vector vs scalar). This paper addresses one such issue, namely heterogeneous vs homogeneous parallel machine organizations. Using simple performance and cost models, we argue that multiprocessors based on a fast global control unit capable of fast execution of serial code, and capable of managing an ensemble of slower processors, offer a performance/ cost ratio significantly better than any comparable homogeneous multiprocessor with distributed control. Although the issue of "deliverable" performance is an open question, it appears that such systems can achieve faster execution and higher program speedups at a much lower cost. © 1991.