Adaptive Checkpointing Schemes for Fault Tolerance in Real-Time Systems with Task Duplication

Dynamic adaptation techniques based on checkpointing is studied in this paper. Placing store-checkpoints and compare-checkpoints between CSCP (store-and-compare-checkpoint), we first present adaptive checkpointing schemes in which the checkpointing interval for a task is dynamically adjusted on line. Introducing the overheads of comparison and storage, the average execution times to complete a task for proposed schemes are obtained, using renewal equations. Further, we have discussed analytically the optimal numbers of checkpoints that minimize the average execution times. We then extend proposed schemes to a set of multiple tasks in real-time systems. Simulation results show that compared to previous method, the proposed approach significantly increases the likelihood of timely task completion.