Event history based sparse state saving in Time Warp

The paper presents a sparse state saving scheme for Time Warp parallel discrete event simulation. The scheme bases the selection of the states to be recorded on the event history of the logical processes. To this purpose, statistics on the virtual time advancement of the processes are collected for the prediction of virtual time intervals that are likely to contain rollback points; the states corresponding to the starting point of those intervals are recorded as checkpoints in order to reduce the average coasting forward. The percentage of states to be recorded is defined by a parameter whose value is dynamically recalculated on the basis of the online observation of the variation of a checkpointing rollback cost function. Simulation results of synthetic workloads are presented for a performance comparison with previous schemes.