Cost analysis of optimistic recovery model for forked checkpointing

Forked checkpointing scheme is proposed to achieve low checkpoint overhead. When a process wants to take a checkpoint in the forked checkpointing scheme, it creates a child process and continues its normal computation. Two recovery models can be used for forked checkpointing when the parent process fails before the child process establishes the checkpoint. One is the pessimistic recovery model where the recovery process rolls back to the previous checkpoint state. The other is the optimistic recovery model where a recovery process waits for the checkpoint to be established by the child process. In this paper, we present the recovery models for forked checkpointing by deriving the expected execution time of a process with and without checkpointing and also show that the expected recovery time of the optimistic recovery model is smaller than that of the pessimistic recovery model.