Sunstone: A Scalable and Versatile Scheduler for Mapping Tensor Algebra on Spatial Accelerators.

Tensor algebra, the main component of several popular machine learning techniques, benefits from modern accelerators due to the massive parallelism and data reuse available. To achieve the benefits, however, optimizing the dataflow is crucial: prior works showed that 19x energy savings are possible by tuning the dataflow. This optimization is challenging because: (1) the optimization space for modern chip architectures with several levels of memory and multiple levels of spatial processing is vast, and (2) distinct tensor computations follow different memory access and reuse patterns. In this manuscript, we algebraically analyze the possible reuse when executing tensor workloads on an accelerator. Based on our analysis, we develop several principles that significantly reduce the dataflow optimization space even for modem, complex chip architectures. Moreover, these principles are transferable to various tensor workloads with different memory access patterns. Compared to prior work, our techniques can find dataflow for typical tensor workloads up to 800x faster and with up to 1.9x better energy-delay products.