An evaluation of implementations of the CMB parallel simulation algorithm on distributed memory multicomputers

Abstract

A model of a message passing network is used to analyze the behavior of three implementations of the Chandy-Misra-Bryant (CMB) parallel simulation algorithm. The characteristics of the model, the organization of the logical processes (LPs) that constitute the simulator and the characteristics of the host parallel computer have a definite influence on the achieved performance, measured in terms of speedup. Large, loaded models help CMB to synchronize with a minimum overhead, efficiently exploiting the available parallelism. Mapping several LPs onto each processor achieves a better use of the available processing power, because while an LP is blocked (synchronizing) others can use the CPU. However, it is not convenient to map too many LPs onto each processor because the synchronization cost would be too high. The communication demands of CMB reduce its efficiency in environments where the cost of passing messages is too high: the performance of CMB running on a network of workstations is quite poor; in contrast, good speedups can be achieved using commercial multicomputers.