Abstract: Scalabihty is a important concept for analyzing the performance of parallel computing systems. Heterogeneous systems have become more common, but few study for heterogeneous system's scalability.This paper first presented a definition of efficiency that can be fit for homogeneous parallel computing systems and heterogeneous parallel compuling systems. According to this definition, this paper also presented a iso-efficiency model that can be applied to both heterogeneous systems and homogeneous systems. From this we can analyze the change circumstance of the system scale and the question scale in which the efficiency maintains consistent. Finally, the paper presented some experiments,the results show that this model can estimates preferably the efficiency and high scalability of parallel computing systems.

Key words: Parallel computing, Performance, Speedup, ISO-efficiency, High scalability