Optimization of Parallel Discrete Event Simulator for Multi-core Systems

Parallel Discrete Event Simulation (PDES) can substantially improve performance and capacity of simulation, allowing the study of larger, more detailed models, in shorter times. PDES is a fine-grained parallel application whose performance and scalability are limited by communication latencies. Traditionally, PDES simulation kernels use processes that communicate using message passing; shared memory is used to optimize message passing for processes running on the same machine. We report on our experiences in implementing a thread-based version of the ROSS simulator. The multithreaded implementation eliminates multiple message copying and significantly minimizes synchronization delays. We study the performance of the simulator on two hardware platforms: a Core i7 machine and a 48-core AMD Opteron Magny-Cours system. We identify performance bottlenecks and propose and evaluate mechanisms to overcome them. Results show that multithreaded implementation improves performance over the MPI version by up to a factor of 3 for the Core i7 machine and 1.2 on Magny-cours for 48-way simulation.