Platform-Specific Optimization and Mapping of Stencil Codes through Refinement

Marcel Köster, Roland Leißa, Sebastian Hack, Richard Membarth, Philipp Slusallek



A straightforward implementation of an algorithm in a general-purpose programming language does usually not deliver peak performance: compilers often fail to automatically tune the code for certain hardware peculiarities like memory hierarchy or vector execution units. Manually tuning the code is firstly error-prone as well as time-consuming and secondly taints the code by exposing those peculiarities to the implementation. A popular method to circumvent these problems is to implement the algorithm in a Domain-Specific Language (DSL). A DSL compiler can then automatically tune the code for the target platform.
In this paper we show how to embed a DSL for stencil codes in another language. In contrast to prior approaches we only use a single language for this task. Furthermore, we offer explicit control over code refinement in the language itself which is used to specialize stencils for particular scenarios. Our first results show that our specialized programs achieve competitive performance compared to hand-tuned CUDA programs.