A fine-grain parallel architecture based on barrier synchronization

Although barrier synchronization has long been considered a useful construct for parallel programming, it has generally been either layered on top of a communication system or used as a completely independent mechanism. Instead, we propose that all communication be made a side-effect of barrier synchronization. This is done by extending the barrier synchronization unit to collect a datum from each processor, compute an aggregate function, and return the corresponding result to each processor. This paper describes a scalable prototype implementation of PAPERS (Purdue´s Adapter for Parallel Execution and Rapid Synchronization). Despite the fact that the prototype is implemented as very simple TTL hardware connecting conventional workstations, measured performance on fine-grain parallel communication operations is far superior to that obtained using conventional workstation networks. It is comparable to the performance of commercially available supercomputers