Parallel direct execution simulation is an important tool for performance and scalability analysis of large message passing parallel programs executing on top of a virtual computer. However, detailed simulation of message-passing codes requires a great deal of computation. We are therefore interested in pursuing implementation techniques which can decrease this cost. One idea is to implement the application virtual processes as lightweight threads rather than traditional Unix processes, reducing both on-processor communication costs and context-switching costs. In this paper we describe an initial implementation of a threadbased parallel directexecution simulator. We discuss the advantages of such an approach and present preliminary results that indicate a signicant improvement over the process-based approach. This work was supported by the National Aeronautics and Space Administration under NASA Contract No. NAS1-19480 while the authors were in residence at the Institute for Compute...
Phillip M. Dickens, Matthew Haines, Piyush Mehrotr