Improving Parallelism of Nested Loops with Non-uniform Dependences
نویسندگان
چکیده
This paper defines the properties of FDT (Flow Dependence Tail set) and FDH (Flow Dependence Head set), and presents two partitioning methods for finding two parallel regions in two-dimensional solution space. One is the region partitioning method by intersection of FDT and FDH. Another is the region partitioning method by two given equations. Both methods show how to determine whether the intersection of FDT and FDH is empty or not. In the case that FDT does not overlap FDH, we will divide the iteration space into two parallel regions by a line. The iterations within each area can be fully executed in parallel. So, we can find two parallel regions for doubly nested loops with non-uniform dependences for maximizing parallelism.
منابع مشابه
An Optimized Three Region Partitioning Technique to Maximize Parallelism of Nested Loops With Non-uniform Dependences
There are many methods for nested loop partitioning exist; however, most of them perform poorly when they partition loops with non-uniform dependences. This paper proposes a generalized and optimized loop partitioning mechanism which can exploit parallelism in nested loops with non-uniform dependences. Our approach based on the region partitioning technique divides the loop into variable size p...
متن کاملCompile Time Partitioning of Nested Loop Iteration Spaces with Non-uniform Dependences*
In this paper we address the problem of partitioning nested loops with non-uniform (irregular) dependence vectors. Parallelizing and partitioning of nested loops requires efficient inter-iteration dependence analysis. Although many methods exist for nested loop partitioning, most of these perform poorly when parallelizing nested loops with irregular dependences. Unlike the case of nested loops ...
متن کاملMinimum dependence distance tiling of nested loops with non-uniform dependences
In this paper we address the problem of partitioning nested loops with non-uniform (irregular) dependence vectors. Although many methods exist for nested loop partitioning, most of these perform poorly when parallelizing nested loops with irregular dependences. We apply the results of classical convex theory and principles of linear programming to iteration spaces and show the correspondence be...
متن کاملFinding Synchronization-Free Slices of Operations in Arbitrarily Nested Loops
This paper presents a new approach for extracting synchronizationfree parallelism being represented by dependent statement instances of an arbitrarily nested loop. Presented algorithms can be applied to both uniform and non-uniform loops. The main advantage is that more synchronization-free parallelism may be extracted than that yielded by existing techniques. Our approach, based on operations ...
متن کاملPolynomial-Time Nested Loop Fusion with Full Parallelism
Data locality and synchronization overhead are two important factors that affect the performance of applications on multiprocessors. Loop fusion is an effective way for reducing synchronization and improving data locality. Traditional fusion techniques, however, either can not address the case when fusion-preventing dependences exist in nested loops, or can not achieve good parallelism after fu...
متن کامل