FantastIC4: A Hardware-Software Co-Design Approach for Efficiently Running 4Bit-Compact Multilayer Perceptrons

• Main Authors: Simon Wiedemann, Suhas Shivapakash, Daniel Becking, Pablo Wiedemann, Wojciech Samek, Friedel Gerfers, Thomas Wiegand
• Format: Article
• Language: English
• Published: IEEE 2021-01-01
• Series: IEEE Open Journal of Circuits and Systems
• Subjects: Deep learning; neural network compression; efficient representation; efficient processing of DNNs; DNN accelerator
• Online Access: https://ieeexplore.ieee.org/document/9440253/

With the growing demand for deploying Deep Learning models to the &#x201C;edge&#x201D;, it is paramount to develop techniques that allow to execute state-of-the-art models within very tight and limited resource constraints. In this work we propose a software-hardware optimization paradigm for obtaining a highly efficient execution engine of deep neural networks (DNNs) that are based on fully-connected layers. The work&#x2019;s approach is centred around compression as a means for reducing the area as well as power requirements of, concretely, multilayer perceptrons (MLPs) with high predictive performances. Firstly, we design a novel hardware architecture named <italic>FantastIC4</italic>, which (1) supports the efficient on-chip execution of multiple compact representations of fully-connected layers and (2) minimizes the required number of multipliers for inference down to only 4 (thus the name). Moreover, in order to make the models amenable for efficient execution on FantastIC4, we introduce a novel entropy-constrained training method that renders them to be robust to 4bit quantization and highly compressible in size simultaneously. The experimental results show that we can achieve throughputs of 2.45 TOPS with a total power consumption of 3.6W on a Virtual Ultrascale FPGA XCVU440 device implementation, and achieve a total power efficiency of 20.17 TOPS/W on a 22nm process ASIC version. When compared to other state-of-the-art accelerators designed for the Google Speech Command (GSC) dataset, FantastIC4 is better by <inline-formula> <tex-math notation="LaTeX">$51\times $ </tex-math></inline-formula> in terms of throughput and <inline-formula> <tex-math notation="LaTeX">$145\times $ </tex-math></inline-formula> in terms of area efficiency (GOPS/mm²).