Bridging pre- and post-silicon debugging with BiPeD

The growing complexity of modern chips has caused an increasing share of the verification effort to shift towards post-silicon validation. This phase is challenged by poor observability, limited off-chip bandwidth, and complex, concurrent communication interfaces. Furthermore, pre-silicon verification and post-silicon validation methodologies are very different and share little information between them. As as result, the diagnosis and debugging of postsilicon failures is very much an ad-hoc and time-consuming task that is largely unable to leverage the vast body of design knowledge available in pre-silicon. We propose BiPeD, a novel methodology to identify the exact time and location of post-silicon bugs. During pre-silicon verification, BiPeD learns the correct behavior of a design's communication patterns. In post-silicon, this knowledge is used to detect errors by means of a reconfigurable hardware unit. When an error is detected, bug reproduction is not necessary: a diagnosis software algorithm analyzes information stored in the hardware unit to provide a wide range of debugging information. We show that our system provides accurate bug localization for a range of failures on the industrial-size OpenSPARC T2 design.