List ranking on processor arrays

List ranking finds for each cell in a linked list the number of cells that precede it in the list. This paper presents a work-efficient list-ranking algorithm for fine-grained processor arrays. This algorithm runs on an array of n/log₂ n processors with the expected run-time of O(log₂ n). As list ranking is highly communication intensive, the proposed algorithm is able to reduce communication cost among processors by assigning sublists, instead of arbitrary cells, of a linked list to each processor. The proposed algorithm is also capable of keeping all processors busy during the whole list-ranking process in order to utilize all processors efficiently.