Reinforcement Learning-Driven Bit-Width Optimization for the High-Level Synthesis of Transformer Designs on Field-Programmable Gate Arrays

Abstract

With the rapid development of deep-learning models, especially the widespread adoption of transformer architectures, the demand for efficient hardware accelerators with field-programmable gate arrays (FPGAs) has increased owing to their flexibility and performance advantages. Although high-level synthesis can shorten the hardware design cycle, determining the optimal bit-width for various transformer designs remains challenging. Therefore, this paper proposes a novel technique based on a predesigned transformer hardware architecture tailored for various types of FPGAs. The proposed method leverages a reinforcement learning-driven mechanism to automatically adapt and optimize bit-width settings based on user-provided transformer variants during inference on an FPGA, significantly alleviating the challenges related to bit-width optimization. The effect of bit-width settings on resource utilization and performance across different FPGA types was analyzed. The efficacy of the proposed method was demonstrated by optimizing the bit-width settings for users’ transformer-based model inferences on an FPGA. The use of the predesigned hardware architecture significantly enhanced the performance. Overall, the proposed method enables effective and optimized implementations of user-provided transformer-based models on an FPGA, paving the way for edge FPGA-based deep-learning accelerators while reducing the time and effort typically required in fine-tuning bit-width settings.