Leveraging Error Compensation to Minimize Time Deviation in Parallel Multi-core Simulations

Abstract

Due to synchronization overhead, it is challenging to apply the parallel simulation techniques of multi-core processors to a larger scale. Although the use of lax synchronization scheme reduces the synchronous overhead and balances the load between synchronous points, it introduces timing errors. To improve the accuracy of lax synchronized simulations, we propose an error compensation technique, which leverages prediction methods to compensate for simulated time deviations due to timing errors. The rationale of our approach is that, in the simulated multi-core processor systems the errors typically propagate via the delays of some pivotal events that connect subsystem models across different hierarchies. By predicting delays based on the simulation results of the preceding pivotal events, our techniques can eliminate errors from the predicted delays before they propagate to the models at higher hierarchies, thereby effectively improving the simulation accuracy. Since the predictions don't have any constraint on synchronizations, our approach largely maintains the scalability of lax synchronization schemes. Furthermore, our proposed mechanism is orthogonal to other parallel simulation techniques and can be used in conjunction with them. Experimental results show error compensation improves the accuracy of lax synchronized simulations by 60.2% and achieves 98.2% accuracy when combined with an enhanced lax synchronization.