Task-Parallel versus Data-Parallel Library-Based Programming in Multicore Systems

Multicore machines are becoming common. There are many languages, language extensions and libraries devoted to improve the programmability and performance of these machines. In this paper we compare two libraries, that face the problem of programming multi-cores from two different perspectives, task parallelism and data parallelism. The Intel threading building blocks (TBB) library separates logical task patterns, which are easy to understand, from physical threads, and delegates the scheduling of the tasks to the system. On the other hand, hierarchically tiled arrays (HTAs) are data structures that facilitate locality and parallelism of array intensive computations with a block-recursive nature following a data-parallel paradigm. Our comparison considers both ease of programming and the performance obtained using both approaches. In our experience, HTA programs tend to be smaller or as long as TBB programs, while performance of both approaches is very similar.