Euripus: A flexible unified hardware memory checkpointing accelerator for bidirectional-debugging and reliability

Bidirectional debugging and error recovery have different goals (programmer productivity and system reliability, respectively), yet they both require the ability to roll-back the program or the system to a past state. This rollback functionality is typically implemented using checkpoints that can restore the system/application to a specific point in time. There are several types of checkpoints, and bidirectional debugging and error-recovery use them in different ways. This paper presents Euripus¹, a flexible hardware accelerator for memory checkpointing which can create different combinations of checkpoints needed for bidirectional debugging, error recovery, or both. In particular, Euripus is the first hardware technique to provide consolidation-friendly undo-logs (for bidirectional debugging), to allow simultaneous construction of both undo and redo logs, and to support multi-level checkpointing for the needs of error-recovery. Euripus incurs low performance overheads (<;5% on average), improves roll-back latency for bidirectional debugging by >;30%, and supports rapid multi-level error recovery that allows >;95% system efficiency even with very high error rates.