Programming effort vs. performance with a hybrid programming model for distributed memory parallel architectures

We investigate here the programming effort and performance of a programming model which is a hybrid between shared memory and message passing. This model permits an easy implementation in shared memory, while still being able to benefit from performance advantages of message-passing for performance critical tasks. We have integrated message-passing with a software DSM system, and evaluated the programming effort and performance with three different applications and various degree of message-passing in the applications. In two of the applications we found that only a small fraction of the source code lines responsible for interprocess communication were performance critical and it was therefore easy to convert only those to message-passing primitives and still approach the performance of pure message-passing.