RISC-V Matrix Extension Specification Proposal V0.6.0

Introduction

This is a matrix extension proposal for AI applications under RISC-V architecture. The extension is currently at version 0.6.0. Compared to the last version, there are following updates:

• Separated source and accumulation registers
  • The source and accumulation registers are separated to tile register and accumulation register, supporting source and destination registers of different sizes;
• More flexible register shape
  • The number of rows and columns in the matrix registers is adjustable, no longer limited to rows = RLEN/32. By adjusting the number of rows and columns, different sizes of matrix multiplication can be formed, achieving full coverage from pure outer products to pure inner products;
• More Element-wise instruction
  • New element-wise instructions have been added to facilitate operator fusion;

The extension is still under construction, and this is a preview demo project. Some key directories are shown below.

|--spec                     ## The RISC-V Matrix Extension specification
|--doc/                     ## The user guide for tools  
    |--shl                  ## The SHL 2.0 user guide
    |--abi                  ## The Matrix Extension ABI Manual
    |--intrinsic            ## The Matrix Extension intrinsic API Reference Manual
|--shl/                     ## A neural networks library using RISC-V Matrix Extension
|--hhb/                     ## A toolkit used for deploying neural network models
|--qemu/                    ## Emulator
|--xuantie-gnu-toolchain/   ## GNU toolchain
    |--riscv-gcc/           ## Compiler
    |--riscv-binutils-gdb/  ## Assembler
|--demos/               
    |--resnet50             ## A resnet50 evaluation demo using nn library
    |--GEMM                 ## A GEMM evaluation demo using intrinsic

Quick Start

Prepare and clone repos.

git clone https://github.com/XUANTIE-RV/riscv-matrix-extension-spec.git
cd riscv-matrix-extension-spec
git submodule update --init

Demo quick start

Several demos in binaries are provided to evaluate RISC-V Matrix Extension's performance. You can quickly start it with the following instructions.

cd demos/
./env.sh
make 
./run.sh

Please refer to the demos/README for details.

Matrix Extension Documents

This project is built using AsciiDoctor (Ruby). The repository has been setup to build the PDF on checkin using GitHub actions. Workflow dependencies are located in the dependencies directory.

For more information on AsciiDoctor, specification guidelines, or building locally, see the RISC-V Documentation Developer Guide.

RISC-V Matrix Extension Specification is kept in ./spec. User guide and reference manual for RISC-V Matrix Extension tools are kept in ./doc.

The final documents form of PDF can be generated using the make command under corresponding folder. The generation method of each document is as follows.

Folder	Command	Documents
spec	make	RISC-V Matrix Extension specification
doc	make shl	SHL 2.0 USER GUIDE
doc	make its	Matrix Extension intrinsic API Reference Manual
doc	make abi	Matrix Extension ABI Manual

Building and Installing RISC-V Matrix Extension project

Prepare the toolchain

cd xuantie-gnu-toolchain/
git submodule update --init

Compile and install qemu. Please refer to the Xuantie qemu project for details.

mkdir qemu/build
cd qemu/build
../configure --target-list="riscv32-linux-user,riscv64-linux-user"
make

Get your own case and compile into matrix.elf. Both intrinsic and nn libraries can be used to perform this step. Please refer to T-HEAD GNU Compiler Toolchain or HHB and SHL for details.

Evaluation matrix performance on qemu with RISC-V Matrix Extension(with vector length set to VLEN and matrix length set to RLEN)

qemu-riscv64 -cpu rv64,x-v=true,vext_spec=v1.0,vlen=VLEN,x-matrix=on,rlen=RLEN ./matrix.elf