Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. We study one of the basic multicore and GPU programming models, namely, SPMD (Single-Program Multiple-Data) programs. We define a formal model of SPMD programs based on interleaving threads that manipulate global and local arrays, and synchronize via barriers. SPMD programs are written with the intention to be deterministic, although programming errors may result in this not being true. SPMD programs are also frequently modified toward optimal performance. These facts motivate us to develop methods to check determinism and equivalence. A key property in achieving this is noninterference formulated as validity of logical formulas automatically derived from the program, that imply determinism. Automatically derived post-conditions can be used to check equivalence of noninterfering programs. We report on a prototype that can prove non-interference of NVIDIA CUDA programs. Copyright © 2010, by the author(s).All rights reserved.Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. This work is dedicated to the memory of Amir Pnueli.
AbstractWe study one of the basic multicore and GPU programming models, namely, SPMD (Single-Program Multiple-Data) programs. We define a formal model of SPMD programs based on interleaving threads that manipulate global and local arrays, and synchronize via barriers. SPMD programs are written with the intention to be deterministic, although programming errors may result in this not being true. SPMD programs are also frequently modified toward optimal performance. These facts motivate us to develop methods to check determinism and equivalence. A key property in achieving this is noninterference, formulated as validity of logical formulas automatically derived from the program, that imply determinism. Automatically derived post-conditions can be used to check equivalence of noninterfering programs. We report on a prototype that can prove non-int...