Mining simulation metrics for failure triage in regression testing

Design debugging poses a major bottleneck in modern VLSI CAD flows, consuming up to 60% of the verification cycle. The debug pain, however, worsens in regression verification flows at the pre-silicon stage where myriads of failures can be exposed. These failures need to be properly grouped and distributed among engineers for further analysis before the next regression run commences. This high-level and complex debug problem is referred to as failure triage and largely remains a manual task in the industry. In this paper, we propose an automated failure triage flow that mines information from both failing and passing tests during regression, and automatically performs a coarse-grain partitioning of the failures. The proposed framework combines formal tools and novel statistical metrics to quantify the likelihood of specific design components being the root-cause of the observed failures. These components are then used to represent failures as high-dimensional objects, which are grouped by applying data-mining clustering algorithms. Finally, the generated failure clusters are automatically prioritized and passed to the best suited engineers for detailed analysis. Experimental results show that the proposed approach groups related failures together with 90% accuracy on the average, and efficiently prioritizes the responsible design errors for 86% of the exposed failures.