Observed Memory Bandwidth and Power Usage on FPGA Platforms with OneAPI and Vitis HLS: A Comparison with GPUs.

The two largest barriers to adoption of FPGA platforms for HPC applications are the difficulty of programming FPGAs and the performance gap when compared to GPUs. To address the first barrier, new ecosystems like Intel oneAPI, and Xilinx Vitis HLS aim to improve programmability for FPGA platforms. From a performance aspect, FPGAs trade off lower compute frequencies for more customized hardware acceleration and power efficiency when compared to GPUs. The performance for memory-bound applications on recent GPU platforms like NVIDIA’s H100 and AMD’s MI210 has also improved due to the inclusion of high-bandwidth memories (HBM), and newer FPGA platforms are also starting to include HBM in addition to traditional DRAM. To understand the current state-of-the-art and performance differences between FPGAs and GPUs, we consider realized memory bandwidth for recent FPGA and GPU platforms. We utilize a custom STREAM benchmark to evaluate two Intel FPGA platforms, the Stratix 10 SX PAC and Bittware 520N-MX, two AMD/Xilinx FPGA platforms, the Alveo U250 and Alveo U280, as well as GPU platforms from NVIDIA and AMD. We also extract power measurements and estimate memory bandwidth per Watt ((GB/s)/W) on these platforms to evaluate how FPGAs compare against GPU execution. While the GPUs far exceed the FPGAs in raw performance, the HBM equipped FPGAs demonstrate a competitive performance-power balance for larger data sizes that can be easily implemented with oneAPI and Vitis HLS kernels. These findings suggest a potential sweet spot for this emerging FPGA ecosystem to serve bandwidth limited applications in an energy-efficient fashion.