Exploiting variable grain parallelism at runtime

摘要

Currently, almost all parallel implementations of programs fix the granularity at which parallelism is exploited at design time. Depending on the application structure and the parallel hardware structure, the programmer decides to exploit parallelism at a fine granularity or coarse granularity or some intermediate granularity, but this granularity is not changed at runtime. In this paper we argue that for many applications fixing the granularity in advance is not a good strategy. Instead it is advantageous to decide the granularity at which parallelism is exploited at runtime, as a function of the available hardware resources and as a function of the overheads associated with going to a finer granularity. We present experimental results from a parallel implementation of a geometric constraint satisfaction system to support our thesis. Our results show a significant advantage in using adaptive parallelism.