This research addresses the problem of providing efficient, protected communication in an SMP cluster.
Traditional approaches use either custom hardware of system-calls.
This paper analyzes a new approach that uses an idle SMP processor to run a message proxy, a communication process that provides protected access to the network. We implement a message proxy and measure in detail the resulting communication overheads between a pair of IBM Model G30 SMPs. We derive a performance model that shows that cache-miss latency within an SMP influences message proxy performance significantly. We compare the performance of message proxies with custom hardware and system calls. Using system-calls results in the poorest performance.