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
Phone: (609) 258-2085
Fax: (609) 964-1699
Administrative Assistant: Pamela DelOrefice, (609) 258-5551

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

Publications

Commutative Set: A Language Extension for Implicit Parallel Programming [abstract] (ACM DL, PDF)
Prakash Prabhu, Soumyadeep Ghosh, Yun Zhang, Nick P. Johnson, and David I. August
Proceedings of the 32nd ACM SIGPLAN Conference on Programming Language Design and Implementation (PLDI), June 2011.
Accept Rate: 23% (55/236).

Sequential programming models express a total program order, of which a partial order must be respected. This inhibits parallelizing tools from extracting scalable performance. Programmer written semantic commutativity assertions provide a natural way of relaxing this partial order, thereby exposing parallelism implicitly in a program. Existing implicit parallel programming models based on semantic commutativity either require additional programming extensions, or have limited expressiveness. This paper presents a generalized semantic commutativity based programming extension, called Commutative Set (CommSet), and associated compiler technology that enables multiple forms of parallelism. CommSet expressions are syntactically succinct and enable the programmer to specify commutativity relations between groups of arbitrary structured code blocks. Using only this construct, serializing constraints that inhibit parallelization can be relaxed, independent of any particular parallelization strategy or concurrency control mechanism. CommSet enables well performing parallelizations in cases where they were inapplicable or non-performing before. By extending eight sequential programs with only 8 annotations per program on average, CommSet and the associated compiler technology produced a geomean speedup of 5.7x on eight cores compared to 1.5x for the best non-\commset parallelization.