Accuracy vs. performance in parallel simulation of interconnection networks

Parallel simulation is emerging as the dominant technique for studying parallel computers. However, the interconnection networks of these machines can be modeled at many different levels of abstraction, allowing researchers to trade off accuracy and performance. In this paper, we use the Wisconsin Wind Tunnel, a parallel simulator for cache-coherent shared-memory machines, to study the trade-offs of accuracy versus performance for six different network simulation models. We evaluate these models for a variety of parallel applications, cachecoherence protocols, and topologies. We show that only the two most expensive models—which model contention at individual links—are robust in the presence of high network loads or non-uniform traffic patterns.