Contention resolution on a broadcast-based distributed shared memory multiprocessor

The issue of resolving remote memory access contention on hardware distributed shared memory multiprocessors and the performance impact of implementing a contention resolution algorithm are focused. After summarising a multiprocessor architecture called the simultaneous multiprocessor optical exchange-bus (SOME-Bus), a simple but effective contention resolution algorithm that relies on the information of the number of messages in the channel queue reported by each node is presented. The algorithm detects potential hot spots and resolves contention using dynamic page migration protocol, and balances remote memory accesses across the nodes of the system. Simulations with eight parallel codes on a 64-processor SOME-Bus show that the algorithm yields significant performance improvements such as balanced-memory load, reduction in the execution times, number of remote memory accesses, average channel waiting times and average network latencies.