oneAPI Threading Building Blocks (oneTBB) is a runtime-based parallel programming model for C++ code that uses threads. It consists of a template-based runtime library to help you harness the latent performance of multi-core processors.
oneTBB enables you to simplify parallel programming by breaking computation into parallel running tasks. Within a single process, parallelism is carried out through threads, an operating system mechanism that allows the same or different sets of instructions to be executed simultaneously.
Here you can see one of the possible executions of tasks by threads.
Use oneTBB to write scalable applications that:
Specify logical parallel structure instead of threads
Emphasize data-parallel programming
Take advantage of concurrent collections and parallel algorithms
oneTBB supports nested parallelism and load balancing. It means that you can use the library without being worried about oversubscribing a system.
oneTBB is available as a stand-alone product and as part of the Intel® oneAPI Base Toolkit.
Refer to the oneTBB System Requirements.
Download oneTBB as a stand-alone product or as a part of the Intel(R) oneAPI Base Toolkit. See Installation Guide for a stand-alone version (Windows* OS and Linux* OS) and Intel(R) oneAPI Toolkits Installation Guide.
After installing oneTBB, you need to set the environment variables:
Go to the oneTBB installation directory (<install_dir>). By default, <install_dir> is the following:
On Linux* OS:
For superusers (root): /opt/intel/oneapi
For ordinary users (non-root): $HOME/intel/oneapi
On Windows* OS:
<Program Files>\Intel\oneAPI
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
Below you can find a typical example for a oneTBB algorithm. The sample calculates a sum of all integer numbers from 1 to 100.
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;
}
);
The pkg-config tool is used to simplify the compilation line by retrieving information about packages from special metadata files. It helps avoid large hard-coded paths and makes compilation more portable.
Compile a program using pkg-config
To compile a test program test.cpp with oneTBB on Linux* OS and macOS*, provide the full path to search for include files and libraries, or provide a simple line like this:
g++ -o test test.cpp $(pkg-config --libs --cflags tbb)
Where:
--cflags provides oneTBB library include path:
$ pkg-config --cflags tbb`` -I<path-to>/tbb/latest/lib/pkgconfig/../..//include
--libs provides the Intel(R) oneTBB library name and the search path to find it:
$ pkg-config –libs tbb
-L<path to>tbb/latest/lib/pkgconfig/../..//lib/intel64/gcc4.8 -ltbb
If you need NUMA/Hybrid CPU support in oneTBB, you need to make sure that HWLOC* is installed on your system.
HWLOC* (Hardware Locality) is a library that provides a portable abstraction of the hierarchical topology of modern architectures (NUMA, hybrid CPU systems, etc). oneTBB relies on HWLOC* to identify the underlying topology of the system to optimize thread scheduling and memory allocation.
Without HWLOC*, oneTBB may not take advantage of NUMA/Hybrid CPU support. Therefore, it’s important to make sure that HWLOC* is installed before using oneTBB on such systems.
Check HWLOC* on the System
To check if HWLOC* is already installed on your system, run hwloc-ls:
For Linux* OS, in the command line.
For Windows* OS, in the command prompt.
If HWLOC* is installed, the command displays information about the hardware topology of your system. If it is not installed, you receive an error message saying that the command hwloc-ls could not be found.
Install HWLOC*
To install HWLOC*, visit the official Portable Hardware Locality website (https://www-lb.open-mpi.org/projects/hwloc/).
For Windows* OS, binaries are available for download.
For Linux* OS, only the source code is provided and binaries should be built.
On Linux* OS, HWLOC* can be also installed with package managers, such as APT*, YUM*, etc. To do so, run: sudo apt install hwloc.
Use these resources if you need support with oneTBB. |
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Find up-to-date information about the product, including detailed notes, known issues, and changes. |
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Learn to use oneTBB. |
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Find oneTBB implementation in open source. |
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