Parallel application experience with replicated method invocation

We describe and evaluate a new approach to object replication in Java, aimed at improving the performance of parallel programs. Our programming model allows the programmer to define groups of objects that can be replicated and updated as a whole, using reliable, totallyordered broadcast to send update methods to all machines containing a copy. The model has been implemented in the Manta high-performance Java system. We evaluate system performance both with micro benchmarks and with a set of five parallel applications. For the applications, we also evaluate ease of programming, compared to RMI implementations. We present performance results for a Myrinet-based workstation cluster as well as for a wide-area distributed system consisting of four such clusters. The micro benchmarks show that updating a replicated object on 64 machines only takes about three times the RMI latency in Manta. Applications using Manta’s object replication mechanism perform at least as fast as manually optimized versions based on RMI, while keeping the application code as simple as with naive versions that use shared objects without taking locality into account. Using a replication mechanism in Manta’s runtime system enables several unmodified applications to run efficiently even on the wide-area system.