BISMO

BISMO is a programmable FPGA accelerator for few-bit integer matrix multiplication. It offers high-performance matrix multiplication for matrices where each element is a few-bit integer (e.g. 2, 3, 4 ... bits). This is beneficial for applications like quantized neural network inference and approximate computing approaches. It was developed as part of a collaboration between Xilinx Research Labs Ireland and the NTNU Computer Architecture Lab.

Some of its key features are:

• High performance and energy efficiency. On the Avnet Ultra96 board, BISMO can offer 15.4 TOPS of binary matrix multiplication performance while drawing less than 8 W of power.
• Configurable size. The hardware can be scaled up for higher performance, or down to save on FPGA resources and power consumption.
• Runtime scales with precision. The input matrices can have any number of bits specified at runtime. Higher bit-precision will take more time.
• Software-programmable. BISMO comes with a runtime library for ease-of-use, and is also programmable with a simple instruction set to cater for more advanced users.

What's New in BISMO?

• 2019-06-10: BISMO v2 is now released with many improvements and new features. Here's a brief summary:
  • Runtime library
  • Instruction generators with tiling support for large matrices
  • Improved hardware with smaller resource cost
  • Hardware-accelerated parallel-to-serial conversion
  • Support for PYNQ on the Avnet Ultra96 (PYNQU96)
  • Experimental support for cache coherency on (PYNQU96CC)

Requirements

Full Setup on Linux

1. A working sbt setup for Chisel2
2. zsh e.g. sudo apt install zsh on Ubuntu
3. Vivado 2017.4 or later (make sure vivado is in PATH)
4. gcc 4.8 or later
5. verilator e.g. sudo apt install verilator on Ubuntu
6. A supported PYNQ board board with the v2.4 image or later, with network access

Quickstart

Start by cloning BISMO with the --recurse-submodules flag:

git clone --recurse-submodules https://github.com/EECS-NTNU/bismo.git

You can "run" BISMO with this code either in hardware-software cosimulation on a host PC, or on the actual FPGA platform as follows:

Running HW-SW Cosimulation

1. cd bismo
2. PLATFORM=VerilatedTester make emu to run BISMO tests in hardware-software cosimulation.

Running on the FPGA

BISMO is built on a host computer and deployed on a target board. Several PYNQ boards are supported, the example below is for the Avnet Ultra96.

On the host computer:

1. cd bismo
2. make all to generate a Ultra96 deployment package with bitfile and drivers. This will generate a 2x64x2 array at 200 MHz and will take some time to complete.
3. Set PYNQU96_URI to point to the rsync target, including the username, IP address and target directory on the Ultra96 board. For instance export [email protected]:/home/xilinx/bismo
4. make rsync to copy deployment package to the Ultra96. You may be prompted for the password for the specified Ultra96 user.

Afterwards, run the following on a terminal on the target board:

1. On the Ultra96, cd /home/xilinx/bismo/deploy to go into the deployment package.
2. su to go into superuser mode.
3. ./compile_rtlib.sh to compile the driver and runtime library.
4. ./compile_testapp.sh to compile the test application.
5. ./setclk.sh 200 to set the clock to 200 MHz.
6. ./load_bitfile.sh to load the BISMO bitfile.
7. LD_LIBRARY_PATH=$(pwd) ./testapp t to run the BISMO tests.

Documentation

You will find more detailed documentation under the doc folder.

Paper

More details on the hardware design and instruction set can be found in the extended BISMO paper or the presentation from FPL'18. If you find BISMO useful, please use the following citation(s):

article{bismo_trets,
 author = {Umuroglu, Yaman and Conficconi, Davide and Rasnayake, Lahiru and Preusser, Thomas and Sjalander, Magnus},
 title = {Optimizing Bit-Serial Matrix Multiplication for
 Reconfigurable Computing},
 journal = {ACM Transactions on Reconfigurable Technology and Systems},
 year = {2019},
 publisher = {ACM}
}

@inproceedings{bismo,
author = {Umuroglu, Yaman and Rasnayake, Lahiru and Sjalander, Magnus},
title = {BISMO: A Scalable Bit-Serial Matrix Multiplication Overlay for Reconfigurable Computing},
booktitle = {Field Programmable Logic and Applications (FPL), 2018 28th International Conference on},
series = {FPL '18},
year = {2018}
}