David I. August
Professor in the Department of Computer Science, Princeton University
Affiliated with the Department of Electrical Engineering, Princeton University
Ph.D. May 2000, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign

Office: Computer Science Building Room 221
Email: august@princeton.edu
PGP: Public Key
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Fax: (609) 964-1699

Front Page Publication List (with stats) Curriculum Vitae (PDF) The Liberty Research Group


DAFT: Decoupled Acyclic Fault Tolerance [abstract] (SpringerLink, PDF)
Yun Zhang, Jae W. Lee, Nick P. Johnson, and David I. August
The International Journal of Parallel Programming (IJPP), February 2012. Invited.
Special issue composed of "top papers" selected by the Program Committee of the 19th International Conference on Parallel Architectures and Compilation Techniques.

Higher transistor counts, lower voltage levels, and reduced noise margin increase the susceptibility of multicore processors to transient faults. Redundant hardware modules can detect such errors, but software transient fault detection techniques are more appealing for their low cost and flexibility. Recent software proposals double register pressure or memory usage, or are too slow in the absence of hardware extensions, preventing widespread acceptance. This paper presents DAFT, a fast, safe, and memory efficient transient fault detection framework for commodity multicore systems. DAFT replicates computation across multiple cores and schedules fault detection off the critical path. Where possible, values are speculated to be correct and only communicated to the redundant thread at essential program points. DAFT is implemented in the LLVM compiler framework and evaluated using SPEC CPU2000 and SPEC CPU2006 benchmarks on a commodity multicore system. Results demonstrate DAFT's high performance and broad fault coverage. Speculation allows DAFT to reduce the performance overhead of software redundant multithreading from an average of 200% to 38% with no degradation of faultcoverage.