A methodology for the rapid injection of transient hardware errors

Ultra-dependable computing demands verification of fault-tolerant mechanisms in the hardware. The most popular class of verification methodologies, fault-injection, is fraught with a host of limitations. Methods which are rapid enough to be feasible are not based on actual hardware faults. On the other hand, methods which are based on gate-level faults require enormous time resources. This research tries to bridge that gap by developing a new fault-injection methodology for processors based on a register-transfer-language (RTL) fault model. The fault model is developed by abstracting the effects of low-level faults to the RTL level. This process attempts to be independent of implementation details without sacrificing coverage, the proportion of errors generated by gate-level faults that are successfully reproduced by the RTL fault model. A prototype tool, ASPHALT, is described which automates the process of generating the error patterns. The IBM RISC-Oriented Micro-Processor (ROMP) is used as a basis for experimentation. Over 1.5 million transient faults are injected using a gate-level model. Over 97% of these are reproduced with the RTL model at a speedup factor of over 500:1. These results show that the RTL fault model may be used to greatly accelerate fault-injection experiments without sacrificing accuracy.