Deterministic galois: on-demand, portable and parameterless

Non-determinism in program execution can make program development and debugging difficult. In this paper, we argue that solutions to this problem should be on-demand, portable and parameterless. On-demand means that the programming model should permit the writing of non-deterministic programs since these programs often perform better than deterministic ones for the same problem. Portable means that the program should produce the same answer even if it is run on different machines. Parameterless means that if there are machine-dependent scheduling parameters that must be tuned for good performance, they must not affect the output. Although many solutions for deterministic program execution have been proposed in the literature, they fall short along one or more of these dimensions. To remedy this, we propose a new approach, based on the Galois programming model, in which (i) the programming model permits the writing of non-deterministic programs and (ii) the runtime system executes these programs deterministically if needed. Evaluation of this approach on a collection of benchmarks from the PARSEC, PBBS, and Lonestar suites shows that it delivers deterministic execution with substantially less overhead than other systems in the literature.