A High Energy Efficient Reconfigurable Hybrid Neural Network Processor for Deep Learning Applications

Abstract

Hybrid neural networks (hybrid-NNs) have been widely used and brought new challenges to NN processors. Thinker is an energy efficient reconfigurable hybrid-NN processor fabricated in 65-nm technology. To achieve high energy efficiency, three optimization techniques are proposed. First, each processing element (PE) supports bit-width adaptive computing to meet various bit-widths of neural layers, which raises computing throughput by 91% and improves energy efficiency by $1.93 \times $ on average. Second, PE array supports on-demand array partitioning and reconfiguration for processing different NNs in parallel, which results in 13.7% improvement of PE utilization and improves energy efficiency by $1.11 \times $ . Third, a fused data pattern-based multi-bank memory system is designed to exploit data reuse and guarantee parallel data access, which improves computing throughput and energy efficiency by $1.11 \times $ and $1.17 \times $ , respectively. Measurement results show that this processor achieves 5.09-TOPS/W energy efficiency at most.