Utilizing Global Simulation Information in Conservative Parallel Simulation on Shared Memory Multiprocessors

Abstract

Global simulation information is accessible on shared memory multiprocessors and can improve the efficiency of parallel simulation. However, most existing concurrent simulators do not aggressively exploit this information. In this paper, we propose a Directly Accessing Information (DAI) scheme, a conservative simulation scheme that collects useful global simulation information in shared memory systems to reduce non-essential blocking and resolve local deadlocks. A parallel queueing network simulator was constructed on a Sequent Symmetry multiprocessor. Special implementation techniques were used to eliminate locking mechanisms for accessing global simulation information. Also, search pruning techniques were developed to reduce the amount of global simulation information used to unblock Logical Processes (LPs). Experimental results demonstrate that the DAI scheme achieves good speedups and substantially outperforms conventional conservative schemes in a reasonably large problem domain where message densities are larger than approximately 0.75.