MasterMind: Many-Accelerator SoC Architecture for Real-Time Brain-Computer Interfaces

Hierarchical Wasserstein Alignment (HiWA) is one of the most promising Brain-Computer Interface algorithms. To enable its real-time communication with the brain and meet low-power requirements, we design and prototype a Linux-supporting, RISC-V based SoC that integrates multiple hardware accelerators. We conduct a thorough design-space exploration at the accelerator level and at the SoC level. With FPGA-based experiments, we show that one of our area-efficient SoCs provides 91x performance and 37x energy efficiency gains over software execution on an embedded processor. We further improve our gains (up to 3408x and 497x, respectively) by parallelizing the workload on multiple accelerator instances and by adopting point-to-point accelerator communication, which reduces memory accesses and software-synchronization overheads. The results include comparisons with multi-threaded software implementations of HiWA running on an Intel i7 and ARM A53 as well as a projection analysis showing that an ASIC implementation of our SoC would meet the needs of real-time Brain-Computer Interfaces.