AutoDSE: Enabling Software Programmers to Design Efficient FPGA Accelerators

Adopting FPGA as an accelerator in datacenters is becoming mainstream for customized computing, but the fact that FPGAs are hard to program creates a steep learning curve for software programmers. Even with the help of high-level synthesis (HLS), accelerator designers still must manually perform code reconstruction and cumbersome parameter tuning to achieve the optimal performance. While many learning models have been leveraged by existing work to automate the design of efficient accelerators, the unpredictability of modern HLS tools becomes a major obstacle for them to maintain high accuracy. We address this problem by incorporating an automated DSE framework - AutoDSE - that leverages bottleneck-guided gradient optimizer to systematically find a better design point. AutoDSE finds the bottleneck of the design in each step and focuses on high-impact parameters to overcome that, which is like the approach an expert would take. The experimental results show that AutoDSE is able to find the design point that achieves, on the geometric mean, 19.9x speedup over one CPU core for Machsuite and Rodinia benchmarks and 1.04x over the manually designed HLS accelerated vision kernels in Xilinx Vitis libraries yet with 26x reduction of their optimization pragmas.