UNDEAD: Detecting and Tolerating Deadlocks in Production Software

Deadlocks are critical problems afflicting parallel applications, causing software to hang with no further progress. Existing detection tools suffer not only from significant recording performance overhead, but also from excessive memory and/or storage overhead. In addition, they may generate numerous false alarms. Subsequently, after problems have been reported, tremendous manual effort is required to confirm and fix these deadlocks. This paper designs a novel system, UNDEAD, that helps defeat deadlocks in production software. Different from existing detection tools, UNDEAD imposes negligible runtime performance overhead (less than 3% on average) and small memory overhead (around 6%), without any storage consumption. After detection, UNDEAD automatically strengthens erroneous programs to prevent future occurrences of both existing and potential deadlocks, which is similar to the existing work—Dimmunix. However, UNDEAD exceeds Dimmunix with several orders of magnitude lower performance overhead, while eliminating numerous false positives. Extremely low overhead, low memory overhead, convenience, and automatic prevention make UNDEAD an always-on detection tool, and a “band-aid” prevention system for production software.