Performance-oriented synchronisation migration in a DOACROSS loop

A statement-level migration of synchronisation operation for performance enhancement is proposed. Theorems show that system performance is enhanced if the number of array elements in the maximal backward synchronisation region is reduced. This task is divided into three steps. First the redundant statements are moved out of the maximal backward synchronisation region by dependence analysis. Secondly, these two statements, which consist of a dependence source and its corresponding sink, respectively, are rewritten to reduce the range of the maximal backward synchronisation region. Finally, the redundant array elements are moved out of the maximal backward synchronisation region. Nine perfect benchmarks are employed to evaluate the performance enhancement after migration. Experimental results show that the enhancement is very significant