RV-CVP: A Flexible Variable Precision RISC-V ISA Extension for Convolutional Neural Network

Jingyi Zhu, Di Zhao*, Weifeng Zhang*, Zhijie Jia, Boran Liu, Guokai Chen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Convolutional neural network (CNN) performs well in several research fields and achieves high accuracy. With the development of CNNs, various hardware acceleration methods have been proposed. Instruction Set Architecture (ISA) based acceleration methods are gaining attention by providing flexibility and efficiency. Meanwhile, for mobile or embedded environments, there is a preference for variable precision quantization data to meet different accuracy or performance requirements. In this paper, we design a new RISC-V ISA extension, named RV-CVP, which supports variable precision specifically for CNNs. It has 3 computational instructions for CNNs and 3 memory access instructions that closely match the computation. We implement the RV-CVP extension on the open-source processor NutShell. Then a CNN programming library is developed, which allows flexible use of the RV-CVP instructions and building CNN models. Finally, we implement our design in simulation and FPGA platforms and evaluate the code density, performance, hardware resource usage, and power consumption. The results show that the RV-CVP extension improves instruction density by up to 1.678x and program performance by up to 42.06x at the single operator level. While on real CNN models, the RV-CVP extension improves performance by 3.8x–4.4x. The code is available at https://gitee.com/OpenBPU/RV-CVP.

Original languageEnglish
Title of host publicationNetwork and Parallel Computing - 20th IFIP WG 10.3 International Conference, NPC 2024, Haikou, China, December 7–8, 2024, Proceedings
EditorsXu Chen, Geyong Min, Deke Guo, Xia Xie, Lingjun Pu
PublisherSpringer Science and Business Media Deutschland GmbH
Pages461-473
Number of pages13
ISBN (Print)9789819628292
DOIs
Publication statusPublished - 2025
Externally publishedYes
Event20th IFIP WG 10.3 International Conference on Network and Parallel Computing, NPC 2024 - Haikou, China
Duration: 7 Dec 20248 Dec 2024

Publication series

NameLecture Notes in Computer Science
Volume15527 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference20th IFIP WG 10.3 International Conference on Network and Parallel Computing, NPC 2024
Country/TerritoryChina
CityHaikou
Period7/12/248/12/24

Keywords

  • Convolutional Neural Network
  • RISC-V
  • Variable Precision

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