Maximizing level of confidence for non-equidistant Checkpointing

Employing fault tolerance often introduces a time overhead, which may cause a deadline violation in real-time systems (RTS). Therefore, for RTS it is important to optimize the fault tolerance techniques such that the probability to meet the deadlines, i.e. the Level of Confidence (LoC), is maximized. Previous studies have focused on evaluating the LoC for equidistant checkpointing. However, no studies have addressed the problem of evaluating the LoC for non-equidistant checkpointing. In this work, we provide an expression to evaluate the LoC for non-equidistant checkpointing, and propose the Clustered Checkpointing method that distributes a given number of checkpoints with the goal to maximize the LoC. The results show that the LoC can be improved when non-equidistant checkpointing is used.