Speculative parallelization of partially parallel loops (2000) [4 citations — 2 self]
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Abstract:
Abstract. Current parallelizing compilers cannot identify a significant fraction of parallelizable loops because they have complex or statically insufficiently defined access patterns. We have previously proposed a framework for their identification. We speculatively executed a loop as a doall, and applied a fully parallel data dependence test to determine if it had any cross--processor dependences; if the test failed, then the loop was re--executed serially. While this method exploits doall parallelism well, it can cause slowdowns for loops with even one cross-processor flow dependence because we have to re-execute sequentially. Moreover, the existing, partial parallelism of loops is not exploited. In this paper we propose a generalization of our speculative doall parallelization technique, named Recursive LRPD test, that can extract and exploit the maximum available parallelism of any loop and that limits potential slowdowns to the overhead of the run-time dependence test itself, i.e., removes the time lost due to incorrect parallel execution. The asymptotic time-complexity is, for fully serial loops, equal to the sequential execution time. We present the base algorithm and an analysis of the
Citations
| 299 | Advanced compiler optimizations for supercomputers – Padua, Wolfe - 1986 |
| 193 | A Computer Program to Simulate Semiconductor Circuits – Nagel - 1975 |
| 159 | The LRPD Test: Speculative Run-Time Parallelization of Loops with Privatization and Reduction Parallelization – Rauchwerger, Padua - 1995 |
| 125 | Automatic array privatization – Tu, Padua - 1993 |
| 73 | Array privatization for parallel execution of loops – Li - 1992 |
| 46 | Optimizing Compilers for Supercomputers – Wolfe - 1982 |
| 18 | A Scalable Method for Run-Time Loop Parallelization – Rauchwerger, Amato, et al. - 1995 |
| 16 | DYNA3D: A Nonlinear, Explicit, Three-Dimensional Finite Element Code for Solid and Structural – Whirley, Engelmann - 1993 |
| 10 | Feedback guided dynamic loop scheduling: Algorithms and experiments – Bull - 1998 |
| 6 | Run-time parallelization overhead reduction techniques – Yu, Rauchwerger - 2000 |
| 4 | Gaussian 94, Revision B.1 – Frisch - 1995 |
| 2 | Data dependence and data- analysis of arrays – Maydan, Amarasinghe, et al. - 1992 |
