HP-FFT: A General High-Performance FFT Generator Using High-Level Synthesis

The Fast Fourier Transform (FFT) is a foundational algorithm widely used in fields like digital signal processing and machine learning. While High-Level Synthesis (HLS) tools have boosted the development of customized hardware accelerators in these fields, existing FFT HLS IP libraries often suffer from low throughput and poor usability due to inadequate exploitation of potential parallelism. In constract, many high-throughput RTL FFT designs lack portability and flexibility, limiting their practical adoption. To get rid of this predicament, we conducted an in-depth analysis of the FFT algorithm's loop structure, uncovering hierarchical parallelism to optimize performance. Based on these insights, we developed a general FFT HLS generator, HP-FFT, which supports multiple functionalities and a wide range of customizable parallelism settings to meet diverse user requirements. Experimental results demonstrate that our proposed HLS generator matches or outperforms state-of-the-art RTL/HLS IP libraries or generators, while enabling users to easily generate architectures that balance resource efficiency and high throughput to suit various application needs.