Simple Add Sample

The Simple Add sample demonstrates the simplest programming methods for using SYCL*-compliant buffers and Unified Shared Memory (USM). Additionally, building and running this sample verifies that your development environment is configured correctly for Intel® oneAPI Toolkits.

Property	Description
What you will learn	How to use SYCL*-compliant extensions to offload computations using both buffers and USM.
Time to complete	15 minutes
Category	Getting Started

Purpose

The Simple Add sample is a simple program that adds two large vectors of integers and verifies the results. In this sample, you will see how to use the most basic code in C++ language that offloads computations to a GPU, which includes using USM and buffers.

The basic SYCL implementations explained in the sample includes device selector, USM, buffer, accessor, kernel, and command groups.

Note: See the Base: Vector Add sample to examine another getting started sample you can use to learn more about using the Intel® oneAPI Toolkits to develop SYCL-compliant applications for CPU and GPU devices.

Prerequisites

Optimized for	Description
OS	Ubuntu* 18.04 Windows* 10, 11
Hardware	GEN9 or newer
Software	Intel® oneAPI DPC++/C++ Compiler

Key Implementation Details

This sample provides examples of both buffers and USM implementations for simple side-by-side comparison.

• USM requires an explicit wait for the asynchronous kernel's computation to complete.
• Buffers, at the time they go out of scope, bring main memory in sync with device memory implicitly. The explicit wait on the event is not required as a result.

The program attempts first to run on an available GPU, and it will fall back to the system CPU if it does not detect a compatible GPU. If the program runs successfully, the name of the offload device and a success message is displayed.

Note: For comprehensive information about oneAPI programming, see the Intel® oneAPI Programming Guide. (Use search or the table of contents to find relevant information quickly.

Set Environment Variables

When working with the command-line interface (CLI), you should configure the oneAPI toolkits using environment variables. Set up your CLI environment by sourcing the setvars script every time you open a new terminal window. This practice ensures that your compiler, libraries, and tools are ready for development.

Build the Simple Add Program

Note: If you have not already done so, set up your CLI environment by sourcing the setvars script in the root of your oneAPI installation.

Linux*:

• For system wide installations: . /opt/intel/oneapi/setvars.sh
• For private installations: . ~/intel/oneapi/setvars.sh
• For non-POSIX shells, like csh, use the following command: bash -c 'source <install-dir>/setvars.sh ; exec csh'

Windows*:

• C:\"Program Files (x86)"\Intel\oneAPI\setvars.bat
• Windows PowerShell*, use the following command: cmd.exe "/K" '"C:\Program Files (x86)\Intel\oneAPI\setvars.bat" && powershell'

For more information on configuring environment variables, see Use the setvars Script with Linux* or macOS* or Use the setvars Script with Windows*.

Using Visual Studio Code* (VS Code) (Optional)

You can use Visual Studio Code* (VS Code) extensions to set your environment, create launch configurations, and browse and download samples.

The basic steps to build and run a sample using VS Code include:

1. Configure the oneAPI environment with the extension Environment Configurator for Intel Software Developer Tools.
2. Download a sample using the extension Code Sample Browser for Intel Software Developer Tools.
3. Open a terminal in VS Code (Terminal > New Terminal).
4. Run the sample in the VS Code terminal using the instructions below.

To learn more about the extensions and how to configure the oneAPI environment, see the Using Visual Studio Code with Intel® oneAPI Toolkits User Guide.

On Linux*

Configure the build system

1. Change to the sample directory.

2. Configure the project to use the buffer-based implementation.

   mkdir build
   cd build
   cmake ..
   

   or

   Configure the project to use the Unified Shared Memory (USM) based implementation.

   mkdir build
   cd build
   cmake .. -DUSM=1
   

Build

1. Build the program.

   make cpu-gpu
   

2. Clean the program. (Optional)

   make clean
   

On Windows*

Configure the build system

1. Change to the sample directory.

2. Configure the project to use the buffer-based implementation.

   mkdir build
   cd build
   cmake -G "NMake Makefiles" ..
   

   or

   Configure the project to use the Unified Shared Memory (USM) based implementation.

   mkdir build
   cd build
   cmake -G "NMake Makefiles" .. -DUSM=1
   

Build

1. Build the program.

   nmake cpu-gpu
   

2. Clean the program. (Optional)

   nmake clean
   

Troubleshooting

If an error occurs, you can get more details by running make with the VERBOSE=1 argument:

make VERBOSE=1

If you receive an error message, troubleshoot the problem using the Diagnostics Utility for Intel® oneAPI Toolkits. The diagnostic utility provides configuration and system checks to help find missing dependencies, permissions errors, and other issues. See the Diagnostics Utility for Intel® oneAPI Toolkits User Guide for more information on using the utility.

Run the Simple Add Program

On Linux

1. Change to the output directory.

2. Run the program for Unified Shared Memory (USM) and buffers.

   ./simple-add-buffers
   ./simple-add-usm
   

On Windows

1. Change to the output directory.

2. Run the program for Unified Shared Memory (USM) and buffers.

   simple-add-usm.exe
   simple-add-buffers.exe
   

Example Output

simple-add output snippet changed to:
Running on device:        Intel(R) Gen9 HD Graphics NEO
Array size: 10000
[0]: 0 + 100000 = 100000
[1]: 1 + 100000 = 100001
[2]: 2 + 100000 = 100002
...
[9999]: 9999 + 100000 = 109999
Successfully completed on device.

License

Code samples are licensed under the MIT license. See License.txt for details.

Third-party program Licenses can be found here: third-party-programs.txt.