On the Evolution of Time Horizons in Parallel and Grid Simulations

We analyze the evolution of the local simulation times (LST) in parallel discrete event simulations. The new ingredients introduced are (i) we associate the LST with the nodes and not with the processing elements, and (ii) we propose to minimize the exchange of information between different processing elements by freezing the LST on the boundaries between processing elements for some time of processing and then releasing them by a wide-stream memory exchange between processing elements. The highlights of our approach are (i) it keeps the highest level of processor time utilization during the algorithm evolution, (ii) it takes a reasonable time for the memory exchange, excluding the time consuming and complicated process of message exchange between processors, and (iii) the communication between processors is decoupled from the calculations performed on a processor. The effectiveness of our algorithm grows with the number of nodes (or threads). This algorithm should be applicable for any parallel simulation with short-range interactions, including parallel or grid simulations of partial differential equations.