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The Liberty Research Group

Parallelization Project

Toward a Toolchain for Pipeline Parallel Programming on CMPs [abstract] (PDF)
John Giacomoni, Tipp Moseley, Graham Price, Brian Bushnell, Manish Vachahrajani, and Dirk Grunwald
Proceedings of the 2007 Workshop on Software Tools for Multicore Systems (STMCS), March 2007.

Today's processors exploit the fine grain data parallelism that exists in many applications via ILP design, vector processing, and SIMD instructions. Thus, future gains must come from chip-multiprocessors, which present developers with previously unimaginable computing resources. Programmers can use these resources for coarse-grain data-parallel computation or task parallelism. Given the extensive research history in coarse-grain data parallelism, we argue that the right approach is to invest research effort on task parallelism because it is currently poorly supported in programming languages, operating systems and performance analysis tools. Such an approach encourages refactoring working sequential applications into task-parallel, and in particular pipeline-parallel, applications. Thus, we join the minority chorus that believes the best strategy for developing parallel programs may be to evolve them from sequential implementations.

There are challenges; future multi-core systems are likely to be heterogeneous and consist of many types of cores. Programmers need support in understanding and exploiting such systems. We believe that the systems community needs to focus on building complete toolchains that encompass all four stages of parallel program development for task parallelism: identification, implementation, verification, and runtime system support. This paper discusses this vision and our efforts in developing such a toolchain.