SoftBeam: Precise tracking of transient faults and vulnerability analysis at processor design time

To study system reliability of a next-generation system, we undertake a soft error vulnerability study for a next-generation microprocessor design. Starting from design data for the entire processor, we extend the microprocessor verification methodology to study soft error propagation through microprocessor logic into the architected processor state. We use soft error injection into randomly selected latch bits to (1) identify areas for improvement, (2) derate technology susceptibility by architectural, microarchitectural, and logic masking resulting in increased soft error resilience; and (3) identify areas where microarchitectural data corruption can be tolerated as performance degradation without impact on correctness, yielding even greater soft error resilience. Based on these results, we reduce design vulnerability to soft errors by factors ranging from 2 for an execution unit to more than 32 for a memory management unit.