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Low-precision Floating-point Arithmetic for High-performance FPGA-based CNN Acceleration

delete2021-11-09
delete24
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OA
AI
C
Chen Wu
M
Mingyu Wang
X
Xinyuan Chu
王琨 cover
王琨 (Kun Wang)
L
Lei He *
DOI:10.1145/3474597delete
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Abstract

Abstract

En 中文
Low-precision data representation is important to reduce storage size and memory access for convolutional neural networks (CNNs). Yet, existing methods have two major limitations: (1) requiring re-training to maintain accuracy for deep CNNs and (2) needing 16-bit floating-point or 8-bit fixed-point for a good accuracy. In this article, we propose a low-precision (8-bit) floating-point (LPFP) quantization method for FPGA-based acceleration to overcome the above limitations. Without any re-training, LPFP finds an optimal 8-bit data representation with negligible top-1/top-5 accuracy loss (within 0.5%/0.3% in our experiments, respectively, and significantly better than existing methods for deep CNNs). Furthermore, we implement one 8-bit LPFP multiplication by one 4-bit multiply-adder and one 3-bit adder, and therefore implement four 8-bit LPFP multiplications using one DSP48E1 of Xilinx Kintex-7 family or DSP48E2 of Xilinx Ultrascale/Ultrascale+ family, whereas one DSP can implement only two 8-bit fixed-point multiplications. Experiments on six typical CNNs for inference show that on average, we improve throughput by 1.5x over existing FPGA accelerators. Particularly for VGG16 and YOLO, compared to six recent FPGA accelerators, we improve average throughput by 3.5x and 27.5x and average throughput per DSP by 4.1x and 5x, respectively.
Keywords:
Low-precision floating-point
CNN
deep learning
FPGA processor
FPGA acceleration

Journal

ACM Transactions on Reconfigurable Technology and Systems cover
ACM Transactions on Reconfigurable Technology and Systems
IF:
2.8
Papers:
597
Citations:
810

Organization

University of California System cover
University of California System
Scholars:
37.5W
Papers: 33.7W
Citations: 6.6K