Automatically exploiting cross-invocation parallelism using runtime information.

Autor: Huang, Jialu, Jablin, Thomas B., Beard, Stephen R., Johnson, Nick P., August, David I.
Zdroj: Proceedings of the 2013 IEEE/ACM International Symposium on Code Generation & Optimization (CGO); 2013, p1-11, 11p
Abstrakt: Automatic parallelization is a promising approach to producing scalable multi-threaded programs for multicore architectures. Many existing automatic techniques only parallelize iterations within a loop invocation and synchronize threads at the end of each loop invocation. When parallel code contains many loop invocations, synchronization can easily become a performance bottleneck. Some automatic techniques address this problem by exploiting cross-invocation parallelism. These techniques use static analysis to partition iterations among threads to avoid crossthread dependences. However, this partitioning is not always achievable at compile-time, because program input determines dependence patterns at run-time. By contrast, this paper proposes DOMORE, the first automatic parallelization technique that uses runtime information to exploit additional cross-invocation parallelism. Instead of partitioning iterations statically, DOMORE dynamically detects crossthread dependences and synchronizes only when necessary. DOMORE consists of a compiler and a runtime library. At compile time, DOMORE automatically parallelizes loops and inserts a custom runtime engine into programs. At run-time, the engine observes dependences and synchronizes iterations only when necessary. For six programs, DOMORE achieves a geomean loop speedup of 2.1× over parallel execution without cross-invocation parallelization and of 3.2 × over sequential execution on eight cores. [ABSTRACT FROM PUBLISHER]
Databáze: Complementary Index