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We describe Genesis, a language for the generation of synthetic programs for use in machine learning-based performance auto-tuning. The language allows users to annotate a template program to customize its code using statistical distributions and to generate program instances based on those distributions. This effectively allows users to generate training programs whose characteristics or features vary in a statistically controlled fashion. We describe the language constructs, a prototype preprocessor for the language, and three case studies that show the ability of Genesis to express a range of training programs in different domains. We evaluate the preprocessor's performance and the statistical quality of the samples it generates. We believe that Genesis is a useful tool for generating large and diverse sets of programs, a necessary component when training machine learning models for auto-tuning.

We propose and evaluate a novel strategy for tuning the performance of a class of stencil computations on Graphics Processing Units. The strategy uses a machine learning model to predict the optimal way to load data from memory followed by a heuristic that divides other optimizations into groups and exhaustively explores one group at a time. We use a set of 104 synthetic OpenCL stencil benchmarks that are representative of many real stencil computations. We first demonstrate the need for auto-tuning by showing that the optimization space is sufficiently complex that simple approaches to determining a high-performing configuration fail. We then demonstrate the effectiveness of our approach on NVIDIA and AMD GPUs. Relative to a random sampling of the space, we find configurations that are 12%/32% faster on the NVIDIA/AMD platform in 71% and 4% less time, respectively. Relative to an expert search, we achieve 5% and 9% better performance on the two platforms in 89% and 76% less time. We also evaluate our strategy for different stencil computational intensities, varying array sizes and shapes, and in combination with expert search.

We describe Genesis, a language for the generation of synthetic programs. The language allows users to annotate a template program to customize its code using statistical distributions and to generate program instances based on those distributions. This effectively allows users to generate programs whose characteristics vary in a statistically controlled fashion, thus improving upon existing program generators and alleviating the difficulties associated with ad hoc methods of program generation. We describe the language constructs, a prototype preprocessor for the language, and five case studies that show the ability of Genesis to express a range of programs. We evaluate the preprocessor's performance and the statistical quality of the samples it generates. We thereby show that Genesis is a useful tool that eases the expression and creation of large and diverse program sets.