Boyi

A systematic framework for automatically deciding the right execution model for OpenCL applications on FPGAs (FPGA'20)

Overview

This repository contains:

• PART ONE: 11 OpenCL applications on FPGAs
  • Source code of all the optimization combinations under four execution models
  • Detailed resource consumption and absolute performance numbers of our experiments
• PART TWO: an LLVM-based automatic tool to determine whether to use two emerging OpenCL features

This work explores the optimization combinations on FPGAs for four high-level execution models: NDRange kernel (NDR), Single work-item kernel (SWI), NDRange kernel+OpenCL channel (NDR+C), Single work-item kernel+OpenCL channel (SWI+C).

And our goal is to assist OpenCL programmers to determine the most suitable execution model based on the presence or absence of three OpenCL patterns: Atomic Operation (AO), Multi-Pass Scheme (MPS) and Kernel-to-Kernel Communication (KKC).

The 11 OpenCL applications include:

Application	Description	Source
BFS	Breadth-First Search	Chai benchmarks
RSCD	RANSAC	Chai benchmarks
TQH	Task Queue System	Chai benchmarks
HSTI	Histogram	Chai benchmarks
SC	Stream Compaction	Chai benchmarks
PAD	Padding	Chai benchmarks
CEDD	Canny Edge Detection	Chai benchmarks
KM	K-Means	Rodinia benchmarks
MM	Matrix Multiplication	Intel OpenCL demos
MS	Mandelbrot Set	Intel OpenCL demos
PS	Prefix Sum	CUDA demos

For more information, you can refer to Chai benchmarks, Rodinia benchmarks, Intel OpenCL demos and CUDA demos.

PART ONE: OpenCL applications on FPGAs

Software & Hardware Requirement

The evaluation of the work requires Intel Quartus Prime software (including OpenCL SDK for FPGA), its license, and FPGA hardware. The FPGA synthesis software and FPGA hardware used in this work are listed below:

• Quartus Prime Design Software 16.1
• Intel FPGA SDK for OpenCL 16.1
• Intel FPGA Runtime Environment for OpenCL: 16.1
• FPGA board support package (BSP) provided by Terasic
• FPGA device: Terasic DE5a-Net board
• Operating system: Windows 7
• Host compiler: Microsoft Visual Studio 2010

Packet Structure

(Take CEDD application as an example:)

Path	Description
CEDD\	OpenCL application
CEDD_test\	a test sample using baseline.cl(in NDRange\)
cedd.sln	Microsoft Visual Studio project for host program
bin\	host program, AOCX files
device\	top-level OpenCL kernel files
host\src\	host source files
input\	input files
common\	common configuration implementations
NDRange\	source code of all the optimization combinations under NDRange execution model
SWI\	source code of all the optimization combinations under single work-item(SWI) execution model
NDRange+Channel\	source code of all the optimization combinations under NDRange+Channel execution model
SWI+Channel\	source code of all the optimization combinations under SWI+Channel execution model
CEDD_data.xlsx	Detailed resource consumption and absolute performance numbers

Usage

(Take CEDD application as an example:)

We'd recommend you to compile and run the project in CEDD_test\, which implements baseline.cl in NDRange\, through the following steps. After running successfully, you can replace the related code with other code in NDRange\, or SWI\, or NDRange+Channel\ or SWI+Channel\ to try whatever implementations you interested.

NOTE: please make sure to build the OpenCL+FPGA environment before.

1. See Intel FPGA SDK for OpenCL Pro Edition: Getting Started Guide for details of installing Intel OpenCL SDK.
2. Refer to vendor's manual for detailed steps of installing FPGA board and driver. The step of installation can be different for different FPGA board and operating system. For Terasic DE5a-Net board, please refer to DE5a-Net OpenCL Manual

Compiling the OpenCL Kernel

To compile the OpenCL kernel, run:

aoc device\baseline.cl -o bin\baseline.aocx --board <i>\<board></i>

where <board> matches the board you want to target. If you are unsure of the boards available, use the following command to list available boards:

aoc --list-boards

Compiling the Host Program

To compile the host program, build the project in Visual Studio 2010 (or later). The compiled host program will be located at bin\host.

Running the Host Program

Before running the host program, you should have compiled the OpenCL kernel and the host program. To launch the host program, use Ctrl + F5 or the following command:

bin\host

PART TWO: LLVM based automatic tool

Software & Hardware Requirement

In our work, Clang 9.0.0 and LLVM9.0.0 are first installed in Ubuntu 14.04. Please see Getting Started with the LLVM System - Requirements to find detailed software and hardware requirements.

Packet Structure

• The apps folder contains the OpenCL kernel code and the host C/C++ code of the 11 OpenCL applications.
• The Transforms folder mainly contains the LLVM passes for IR analyzation.
• The run.sh file is the shell script.

Usage

Please refer to LLVM's documentations for details of configuring and compiling LLVM. An LLVM getting started guideline can be found here. Or you can start to use our LLVM tool (in a Linux environment) quickly following the steps below:

If you have already finished configuring the LLVM environment, please start with Step 3.

Step 1: Checking out the LLVM project

git clone https://github.com/llvm/llvm-project.git

Step 2: Building LLVM and Clang

cd llvm-project
mkdir build
cmake -DLLVM_ENABLE_PROJECTS=clang -G "Unix Makefiles" ../llvm
make
make install

Then you can try it out:

clang --version

You may get:

clang version 9.0.0 (https://github.com/llvm/llvm-project.git 75afc0105c089171f9d85d59038617fb222c38cd)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin

Step 3: Using Boyi

• Move the apps folder and the run.sh file to the same directory as the llvm-project folder.
• Add all the folders in the analysis_passes folder to the llvm-project/llvm/lib/Transforms folder.
• Copy the following lines into llvm-project/llvm/lib/Transforms/CMakeLists.txt:

  add_subdirectory(HasAO)
  add_subdirectory(NumOfKernels)
  add_subdirectory(IsSameBuff)
  add_subdirectory(IsRdWr)
  add_subdirectory(IsSameMAP)
  add_subdirectory(IsSequential)
  add_subdirectory(VarBuffInHost)
  add_subdirectory(VarBuffInKernel)
  add_subdirectory(Model)
  

• Change directory to llvm-project/.. and run:

  cd llvm-project/..
  /run.sh