Comparative performance evaluation of hot spot contention between min-based and ring-based shared-memory architectures

Abstract-Hot spot contention on a network-based shared-memory architecture occurs when a large number of processors try to access a globally shared variable across the network. While Multistage Interconnection Network (MIN) and Hierarchical Ring (HR) structures are two important bases on which to build large scale shared-memory multiprocessors, the different inter-connection networks and cache/memory systems of the two archl-tectures respond very differently to network bottleneck situations. In this paper, we present a comparative performance evaluation of hot spot effects on the MIN-based and HR-based shared-memory architectures. Both nonblocking MIN-based and HR-based architectures are classified, and analytical models are de-scribed for understanding network differences and for evaluating hot spot performance on both architectures. The analytical com-parisons indicate that HR-based architectures have the potential to handle various contentions caused by hot spots more efficiently than MIN-based architectures. Intensive performance measure-ments on hot spots have been conducted on the BBN TC2000 (MIN-based) and the KSRl (HR-based) machines. Performance experiments were also conducted on the practical experience of hot spots with respect to synchronization lock algorithms. The experimental results are consistent with the analytical models, and present practical observations and an evaluation of hot spots on the two types of architectures. Index Terms-Hierarchical Rings (HR), hot spot, Multistage Interconnection Network (MIN), performance modeling an