Computing Applications Parallel Application Simulation Parallel Simulation of Large-scale Parallel Applications

Accurate and efficient simulation of large parallel applications can be facilitated with the use of direct execution and parallel discrete-event simulation. This paper describes MPI-SIM, a direct execution-driven parallel simulator designed to predict the performance of existing MPI and MPI-IO application. MPI-SIM can be used to predict the performance of these programs as a function of architectural characteristics, including number of processors, message communication latencies, caching algorithms, and alternative implementations of collective I/O operations. Results are presented, which show the use of MPI-SIM in performing a scalability study of real-world applications. The benchmarks chosen for the study include Sweep3D, one of the ASCI benchmarks, and BTIO, an I/O-intensive benchmark from the NAS Parallel Benchmark suite. MPI-SIM is shown to accurately and efficiently predict the performance of Sweep3D running on an Origin 2000. It is also used to demonstrate the impact of the number of I/O nodes on BTIO’s performance.