OSCAR: An Open-Source Flexible and Hierarchical AI Accelerator Generator with Accurate Power Model

With the growing demand for artificial intelligence (AI) applications, high-performance and energy-efficient AI chips are needed to support the computation. However, architectural-level AI chip design, PPA evaluation, and power estimation remain challenging due to the exponential set of possible designs and the difficulty of accurately modeling the impact of diverse dataflows and workflows on the underlying hardware at the architectural-design stage. We propose a novel open-source framework named OSCAR, which, given a set of hardware and workload specifications, provides architecture-level power estimation and can also automatically generate Chisel and synthesizable RTL of the custom AI chip. Our contributions include (1) a flexible and hierarchical AI chip design space, software and hardware stack, and an RTL generator supporting dense, Transformer, Winograd, systolic, and reconfigurable architectures in one unified framework, (2) hierarchy-based data-sensitive power model using architectural-level toggling features, achieving 3.8% error and correlation coefficient R > 0.99 to post-synthesis power, outperforming state-of-the-art power estimation methods, (3) validation of our power model by performing design space exploration, finding designs with better Pareto-optimality, 2.5 × lower power or 2 × better runtime metrics, compared with using prior art power models, (4) a tape-out of an AI chip based on DSE results, with OSCAR modeling its power with over 90% accuracy.