Efficient Index Generation for Compiling Two-Level Mappings in Data-Parallel Programs

This paper presents compilation techniques to compress holes, which are caused by the non-unit alignment stride in a two-level data-processor mapping. Holes are the memory locations mapped by useless template cells. To fully utilize the memory space, memory holes should be removed. In a twolevel data-processor mapping, there is a repetitive pattern for array elements mapped onto processors. We classify blocks into classes and use a class table to record the distribution of each class in the first repetitive data distribution pattern. Similarly, data distribution on a processor also has a repetitive pattern. We use a compression table to record the distribution of each block in the first repetitive data distribution pattern on a processor. By using class table and compression table, hole compression can be easily and efficiently achieved. Compressing holes can save memory usage, improve spatial locality and further increase system performance. The proposed method is efficient, stable an..