Scalable Problems and Memory-bounded Speedup Scalable Problems and Memory-bounded Speedup

In this paper three models of parallel speedup are studied. They are xed-size speedup, xed-time speedup and memory-bounded speedup. The latter two consider the relationship between speedup and problem scalability. Two sets of speedup formulations are derived for these three models. One set considers uneven workload allocation and communication overhead, and gives more accurate estimation. Another set considers a simpliied case and provides a clear picture on the impact of the sequential portion of an application on the possible performance gain from parallel processing. The simpliied xed-size speedup is Amdahl's law. The simpliied xed-time speedup is Gustafson's scaled speedup. The simpliied memory-bounded speedup contains both Amdahl's law and Gustafson's scaled speedup as special cases. This study leads to a better understanding of parallel processing.