Accelerator Design with High-Level Synthesis

Specialized accelerators can exploit spatial parallelism on both operations and data thanks to a dedicated microarchitecture with a better use of the hardware resources. Designers need to describe such components (including the resources, their interconnections, and the control logic) in proper hardware languages compatible with synthesis tools. This process requires hardware design skills that are uncommon in software programmers. To boost the use of spatial accelerators, software programmers need automated methods, like high-level synthesis (HLS), to specify hardware blocks with high-level languages and automatically translate their specifications into the corresponding hardware descriptions ready for synthesis. While HLS is a key enabling technology for the design of complex hardware/software architectures, developing efficient spatial accelerators requires efficient HLS methods to co-optimize performance and hardware cost with a hardware/software co-design approach. In this chapter, we present the current state of the art in high-level synthesis, covering all steps to create the specialized microarchitecture of an accelerator. We also discuss outstanding challenges that can be addressed with the use of HLS.