Parallel Computing in Practice

Examples of deploying and computing with SYCL, OpenCL, Level Zero nd OpenMP on GPU devices for enhanced parallel performance, primarily on the Windows platform.

Setting Up the SYCL Compilation Environment on Windows

Basic Setting

1. Download and install the GPU driver according to the instructions provided in How to Install an Intel® Graphics Driver in Windows® 10 & Windows 11*

2. Download and install the latest oneAPI Base Toolkit from Get the Intel® oneAPI Base Toolkit

   You only need to install the following four components:

   • Intel® oneAPI DPC++/C++ Compiler
   • Intel® oneAPI DPC++ Library
   • Intel® Distribution for GDB
   • Intel® oneAPI Threading Building Blocks.

3. Search for Intel oneAPI Command Prompt for Intel 64 for Visual Studio 2022 in the Windows search bar,

or directly call the oneAPI setvars.bat (usually located in C:\Program Files (x86)\Intel\oneAPI), then type sycl-ls and press Enter to check your SYCL device and backend. If you find a GPU device but no Level Zero backend, and only the OpenCL backend is available, you may consider deleting the registry key [HKEY_LOCAL_MACHINE\SOFTWARE\Khronos\OpenCL]

and then restarting the oneAPI setvars script. Then, you can find that the GPU has both OpenCL backend and Level Zero backend options available.

C:\Program Files (x86)\Intel\oneAPI>setvars.bat
C:\Program Files (x86)\Intel\oneAPI>sycl-ls
[level_zero:gpu][level_zero:0] Intel(R) oneAPI Unified Runtime over Level-Zero, Intel(R) Arc(TM) Graphics 12.71.4 [1.3.29516]
[opencl:gpu][opencl:0] Intel(R) OpenCL Graphics, Intel(R) Arc(TM) Graphics OpenCL 3.0 NEO  [31.0.101.5592]

You can use the environment variable ONEAPI_DEVICE_SELECTOR to specifiy the backend.

Enabling Clang in the oneAPI Compiler

The oneAPI installation package includes tools such as clang, clang++, and other Clang utilities. By default, these are not used, but you can access them using specific commands --include-intel-llvm.

C:\Program Files (x86)\Intel\oneAPI>setvars.bat --include-intel-llvm
C:\Program Files (x86)\Intel\oneAPI>where clang
C:\Program Files (x86)\Intel\oneAPI\compiler\latest\bin\compiler\clang.exe

clang exposes more switches like -emit-llvm, which makes it easier to view the LLVM IR compared to icx.

Configuring the SYCL IntelliSense Environment in VSCode

Please refer to this link

Setting Up the Level Zero Development Environment on Windows

You can directly find the release package at https://github.com/oneapi-src/level-zero. The release package does not include the runtime DLLs. You can build the runtime DLLs, such as ze_loader.dll, yourself.

About Debugging

I recommend checking out this repository to find the release package (e.g., llvm-mingw-20241030-msvcrt-x86_64). After downloading and extracting the package, locate lldb.exe. Then, in the oneAPI setvars environment, launch lldb with your executable, like so

C:\Users\gta\Downloads\llvm-mingw-20241030-msvcrt-x86_64\bin>lldb.exe C:\target.exe