An Energy-Efficient Integrated Programmable Array Accelerator and Compilation Flow for Near-Sensor Ultralow Power Processing

In this paper, we give a fresh look to coarse grained reconfigurable arrays (CGRAs) as ultralow power accelerators for near-sensor processing. We present a general-purpose integrated programmable-array accelerator (IPA) exploiting a novel architecture, execution model, and compilation flow for application mapping that can handle kernels containing complex control flow, without the significant energy overhead incurred by state of the art predication approaches. To optimize the performance and energy efficiency, we explore the IPA architecture with special focus on shared memory access, with the help of the flexible compilation flow presented in this paper. We achieve a maximum energy gain of 2x, and performance gain of 1.33x and 1.8x compared with state of the art partial and full predication techniques, respectively. The proposed accelerator achieves an average energy efficiency of 1617 MOPS/mW operating at 100 MHz, 0.6 V in 28 nm UTBB FD-SOI technology, over a wide range of near-sensor processing kernels, leading to an improvement up to 18x, with an average of 9.23x (as well as a speed-up up to 20.3x, with an average of 9.7x) compared to a core specialized for ultralow power near-sensor processing.