In this paper we concentrate in the efforts made to exploit the performance of Myrinet to build a faster communication route into CoR1. By accessing the Myrinet interface through GM2, we achieved low latency and high bandwidth message passing without the overhead of a higher level protocol stack, system calls or interrupts. CoR is an ongoing project unique in its design goal of combining multithreading, message passing and distributed shared memory with facilities to dynamically select from different transport media and protocols the one that best fits communication and interaction requirements. The ability to mix CoR and PVM calls in the same program brings numerous benefits to the application developer familiar with PVM, notably: 1) new transport communication layers; PvmRouteMyrinet and PvmRouteUdp; 2) migration mechanisms for exploiting fine grain message passing; 3) thread-safe communication PVM API; 4) object-oriented distributed shared memory.
