A Dynamic Parallel Strategy for DOACROSS Loops

Many parallelization methods work on exposing the pipeline/wave-front parallelism of DOACROSS loops through loop transformations. However, these methods statically assign iterations to available threads for parallel execution, and thus causing the waste of computing resources in synchronization among threads, especially in a multithreading environment. This paper proposes a brand-new parallel strategy that achieves wave-front parallelism with reduced dependences and provides dynamic tile assignment for DOACROSS loops, which has better ability to avoid threads from waiting in synchronization and utilize computing resources. The experimental results demonstrate that the proposed strategy outperforms two advanced strategies which are based on implicit barriers and POST/WAIT operations over six benchmarks on a multi-core server. The strategy also has better scalability for the increasing number of threads.