Cost-Effective (and Nearly Overhead-Free) OrderRecording and Data Race Detection

Chip-multiprocessors are becoming the dominant vehicle for general-purpose processing, and parallel software will be needed to effectively utilize them. This parallel software is no-toriously prone to synchronization bugs, which are often dif-ficult to detect and repeat for debugging. While data race de-tection and order-recording for deterministic replay are useful in debugging such problems, only order-recording schemes are lightweight, whereas data race detection support scales poorly and degrades performance significantly. This paper presents our CORD (Cost-effective Order-Recor-ding and Data race detection) mechanism. It is similar in cost to prior order-recording mechanisms, but costs considerably less then prior schemes for data race detection. CORD also has a negligible performance overhead (0.4 % on average) and de-tects most dynamic manifestations of synchronization problems (77 % on average). Overall, CORD is fast enough to run always (even in performance-sensitive production runs) and provides the support programmers need to deal with the complexities of writing, debugging, and maintaining parallel software for future multi-threaded and multi-core machines. 1