An analytical comparison of periodic checkpointing and incremental state saving

The successful application of optimistic synchronization techniques in parallel simulation requires that rollback overheads be contained. The chief contributions to rollback overhead in a Time Warp simulation are the time required to save state information and the time required to restore a previous state. Two competing techniques for reducing rollback overhead are periodic checkpointing (Lin and Lazowska, 1989) and incremental state saving (Bauer et al., 1991). This paper analytically compares the relative performance of periodic checkpointing to incremental state savings. The analytical model derived for periodic checkpointing is based almost entirely on the previous model developed by Lin (Lin and Lazowska, 1989). The analytical model for incremental state saving has been developed for this study. The comparison assumes an optimal checkpoint interval and shows under what simulation parameters each technique performs best.