Harpocrates++: Automated Functional Program Generation Against CPU Faults and Silent Data Corruptions

Several hyperscalers have recently disclosed the occurrence of silent data corruptions (SDCs) in their system fleets, sparking concerns about the severity of known and the existence of unidentified root causes of faults in CPUs. These incidents reveal that CPUs may generate incorrect results due to latent manufacturing defects, variability, marginalities, bugs, and aging. To tackle this, we present Harpocrates, an automated methodology for the generation of short, constrained-random functional test programs that maximize fault detection in target CPU structures and can be employed at different stages of system lifecycle. Harpocrates adopts a hardware-model-in-the-loop approach, iteratively refining the generated test programs via a detailed simulation-based microarchitecture engine that models and grades for multiple fault types. Harpocrates adapts to various program generators, ISAs, microarchitectures, and fault types. Our results on seven important CPU structures show that Harpocrates outperforms open-source test suites in fault detection capability while attaining much shorter generation times.