Low-cost soft error resilience with unified data verification and fine-grained recovery for acoustic sensor based detection

This paper presents Turnstile, a hardware/software cooperative technique for low-cost soft error resilience. Leveraging the recent advance of acoustic sensor based soft error detection, Turnstile achieves guaranteed recovery by taking into account the bounded detection latency. The compiler forms verifiable regions and selectively inserts store instructions to checkpoint their register inputs so that Turnstile can verify the register/memory states with regard to a region boundary in a unified way without expensive register file protection. At runtime, for each region, Turnstile regards any stores (to both memory and register checkpoints) as unverified, and thus holds them in a store queue until the region ends and spends the time of the error detection latency. If no error is detected during the time, the verified stores are merged into memory systems, and registers are checkpointed. When all the stores including checkpointing stores prior to a region boundary are verified, the architectural and memory states with regard to the boundary are verified, thus it can serve as a recovery point. In this way, Turnstile contains the errors within the core without extra memory buffering. When an error is detected, Turnstile invalidates unverified entries in the store queue and restores the checkpointed register values to get the architectural and memory states back to what they were at the most recently verified region boundary. Then, Turnstile simply redirects program control to the verified region boundary and continues execution. The experimental results demonstrate that Turnstile can offer guaranteed soft error recovery with low performance overhead (<8% on average).