Parallel Sorting on Symult 2010

Abstract

In this paper, three sorting algorithms, Bitonic sort, Shell sort and parallel Quicksort are studied. We analyze the performance of these algorithms and compare them with the empirical results obtained from the implementations on the Symult Series 2010, a distributed-memory, message-passing MIMD machine. Each sorting algorithm is a combination of a parallel sort component and a sequential sort component. These algorithms are designed for sorting M elements of random integers on a N-processor machine, where M > N . We found that Bitonic sort is the best parallel sorting algorithm for small problem size, ( M / N ) < 64, and the parallel Quicksort is the best for large problem size. The new Parallel Quicksort algorithm with a simple key selection method achieves a decent speed-up comparing with other versions of parallel Quicksort on similar parallel machines. Although Shell sort has a worse theoretical time complexity, it does achieve linear speedup for large problem size by using a synchronization step to detect early termination of the sorting steps.