Programming with Relaxed Streams

Diminishing returns in single thread performance have forced a reevaluation of priorities in microprocessor design. Recent architectures have foregone deeper pipelining in favor of multiple cores per chip and multiple threads per core. The day approaches when processors with hundreds or thousands of cores are commonplace, but programming models for these manycore architectures lag far behind the architectures themselves. We are developing Fractal, a manycore architecture and associated programming model we call relaxed streaming. Relaxed streaming allows flexible and convenient stream access, implicit memory management and dependency enforcement, and the decoupling of sequential and parallel phases of execution. This paper presents relaxed streaming in the context of our Fractal API, discussing the benefits of a relaxed streaming model over more traditional streaming models, especially in terms of convenience and ease of use.