A novel parallelization technique for DEVS simulation of continuous and hybrid systems

FEDERICO BERGERO; ERNESTO KOFMAN; FRANÇOIS CELLIER

SIMULATION-TRANSACTIONS OF THE SOCIETY FOR MODELING AND SIMULATION INTERNATIONAL

SAGE PUBLICATIONS LTD

Lugar: London; Año: 2012

0037-5497

In this paper, we introduce a novel parallelization technique for DEVS simulation of continuousand hybrid systems. Here, like in most parallel discrete event simulation methodologies, the models are first split into several sub--models that are concurrently simulated on different processors.In order to avoid the cost of the global synchronization of all processes, the simulation time of each sub--model is locally synchronized in a real--time fashion with a scaled version of physical time, which implicitly synchronizes all sub--models.The new methodology, coined Scaled Real--Time Synchronization (SRTS), does not ensure a perfect synchronization in its implementation. However, under certain conditions, the synchronization error introduced only provokes bounded numerical errors in the simulation results.SRTS uses the same physical time--scaling parameter during the entire simulation. We also developed an adaptive version of the methodology lue{(Adaptive-SRTS)} where this parameter automatically evolves during the simulation according to the workload.We implemented the SRTS and Adaptive-SRTS techniques in pd, a DEVS simulation tool, under the lue{Real Time Operating System} (RTOS) RTAI lue{(RealTime Application Interface)}. We also tested its performance in the simulation of three large models, obtaining in all cases a considerable speedup.