A Generic Algorithm Template for Divide-and-Conquer in Multicore Systems

The divide-and-conquer pattern of parallelism is a powerful approach to organize parallelism on problems that are expressed naturally in a recursive way. In fact, recent tools such as Intel Threading Building Blocks (TBB), which has received much attention, go further and make extensive usage of this pattern to parallelize problems that other approaches parallelize following other strategies. In this paper we discuss the limitations to express divide-and-conquer parallelism with the algorithm templates provided by the TBB. Based on our observations, we propose a new algorithm template implemented on top of TBB that improves the programmability of many problems that fit this pattern, while providing a similar performance. This is demonstrated with a comparison both in terms of performance and programmability.