Optimized Communication Patterns on Workstation Clusters Optimized Communication Patterns on Workstation Clusters

The limited communication bandwidth and high startup latencies of clustered workstations restrict their use to problems with sparse communication patterns or good concurrency between calculation and communication. First we describe our modiications to the popular PVMM5] message passing library, and on performance improvements using the PVM package on an FDDI-ring. Applications developed with a parallel communications architecture in mind perform poorly when ported to a message passing library running on workstations with sequential communication. In the second part, we present a dynamic loop scheduling algorithm for the data parallel programming model which optimizes the network usage on such clusters. As a proof of concept we have implemented a basic matrix multiplication and nd a signiicant increase in parallel eeciency.