Barrier synchronization in distributed-memory multiprocessors using rendezvous primitives

Abstract

This paper deals with barrier synchronization in wormhole routed distributed-memory multiprocessors. New rendezvous and multirendezvous synchronization primitives are proposed to implement a barrier between two and multiple processors, respectively. These primitives reduce the number of communication steps required to implement a barrier; thus, significantly reducing the synchronization overhead for networks with high communication start-up cost. Two algorithms for barrier synchronization on k-ary n-cube networks are presented. The rendezvous primitive allows one to synchronize all processors in nlog/sub 2/(k) steps. The multirendezvous primitive allows one to synchronize an arbitrary subset of processors in optimal number of communication steps depending on the ratio of the communication start-up (t/sub s/) to the link-propagation (t/sub p/) cost.<>