Next Steps

Next Steps#

After installing oneTBB, complete the following steps to start working with the library.

Set the Environment Variables#

After installing oneTBB, set the environment variables:

  1. Go to the oneTBB installation directory.

  2. Set the environment variables using the script in <install_dir> by running:

    • On Linux* OS: vars.{sh|csh} in <install_dir>/tbb/latest/env

    • On Windows* OS: vars.bat in <install_dir>/tbb/latest/env

Tip

oneTBB can coordinate with Intel(R) OpenMP on CPU resources usage to avoid excessive oversubscription when both runtimes are used within a process. To enable this feature set TCM_ENABLE environment variable to 1. For more details, see Avoid CPU Overutilization.

Build and Run a Sample#

  1. Create a new C++ project using your IDE. In this example, Microsoft* Visual Studio* Code is used.

  2. Create an example.cpp file in the project.

  3. Copy and paste the code below. It is a typical example of a oneTBB algorithm. The sample calculates a sum of all integer numbers from 1 to 100.

    #include <oneapi/tbb.h>

int main (){
    int sum = oneapi::tbb::parallel_reduce(
        oneapi::tbb::blocked_range<int>(1,101), 0,
        [](oneapi::tbb::blocked_range<int> const& r, int init) -> int {
            for (int v = r.begin(); v != r.end(); v++) {
                init += v;
            }
            return init;
        },
        [](int lhs, int rhs) -> int {
            return lhs + rhs;
        }
    );

    printf("Sum: %d\n", sum);
    return 0;
}

  4. Open the tasks.json file in the .vscode directory and paste the following lines to the args array:

    • -Ipath/to/oneTBB/include to add oneTBB include directory.

    • path/to/oneTBB/ to add oneTBB.

    For example:

    {
   "tasks": [
        {
           "label": "build & run",
           "type": "cppbuild",
           "group": {
           "args": [
               "/IC:\\Program Files (x86)\\Intel\\oneAPI\\tbb\\2022.0.0\\include",
               "C:\\Program Files (x86)\\Intel\\oneAPI\\tbb\\2022.0.0\\lib\\tbb12.lib"

  5. Build the project.

  6. Run the example.

  7. If oneTBB is configured correctly, the output displays Sum: 5050.

  1. Create an example.cpp file in the project.

  2. Copy and paste the code below. It is a typical example of a oneTBB algorithm. The sample calculates a sum of all integer numbers from 1 to 100.

    #include <oneapi/tbb.h>

int main(){
    int sum = oneapi::tbb::parallel_reduce(
        oneapi::tbb::blocked_range<int>(1,101), 0,
        [](oneapi::tbb::blocked_range<int> const& r, int init) -> int {
            for (int v = r.begin(); v != r.end(); v++) {
                init += v;
            }
            return init;
        },
        [](int lhs, int rhs) -> int {
            return lhs + rhs;
        }
    );

    printf("Sum: %d\n", sum);
    return 0;
}

  3. Compile the code using oneTBB. For example,

    g++ -std=c++11 example.cpp -o example -ltbb

  4. Run the executable:

    ./example

  5. If oneTBB is configured correctly, the output displays Sum: 5050.

Enable Hybrid CPU and NUMA Support#

To support Hybrid CPU and NUMA platforms, oneTBB relies on the HWLOC* library.

The HWLOC functionality is accessed through a set of proxy libraries whose names begin with the tbbbind prefix. oneTBB automatically loads them at runtime when needed. To find and load these libraries successfully, locate them in the same directory as the oneTBB library itself (e.g., alongside libtbb.so or tbb.dll).

Starting with oneTBB 2022.2, the default tbbbind library is statically linked with HWLOC 2.x. This version is used if a system-provided HWLOC cannot be found.

If you prefer to use a system-provided or custom-built version of HWLOC, make sure it is available in the search paths used by the dynamic loader. Consult your platform’s dynamic loader documentation for details about these paths (e.g., LD_LIBRARY_PATH on Linux* OS or PATH on Windows* OS).

To use a specific HWLOC version, place one of the following tbbbind variants in the same directory as the oneTBB library:

  • tbbbind_2_5 — depends on HWLOC version 2.5 or higher. Use this version if hybrid CPU support is required.

  • tbbbind_2_0 — depends on HWLOC versions 2.1 to 2.4.

Tip

To confirm that tbbbind is loaded successfully at runtime, set the environment variable TBB_VERSION=1 before launching your application.

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