Machine Learning for Microprocessor Performance Bug Localization

Abstract: The validation process for microprocessors is a very complex task that consumes substantial engineering time during the design process. Bugs that degrade overall system performance, without affecting its functional correctness, are particularly difficult to debug given the lack of a golden reference for bug-free performance. This work introduces two automated performance bug localization methodologies based on machine learning that aims to aid the debugging process. Our results show that, the evaluated microprocessor core performance bugs whose average IPC impact is greater than 1%, our best-performing technique is able to localize the exact microarchitectural unit of the bug $\sim$77\% of the time, while achieving a top-3 unit accuracy (out of 11 possible locations) of over 90% for bugs with the same average IPC impact. The proposed system in our simulation setup requires only a few seconds to perform a bug location inference, which leads to a reduced debugging time.