thread-pool

A modern, fast, lightweight thread pool library based on C++20

Programming language: C++

License: MIT License

Tags: Concurrency     Parallel Processing     Threadpool     C++     C++20     C++23    

README

thread-pool

A simple, functional thread pool implementation using pure C++20.

Features

• Built entirely with C++20
• Enqueue tasks with or without tracking results

Integration

dp::thread-pool is a header only library. All the files needed are in include/thread_pool.

CMake

ThreadPool defines two CMake targets:

• ThreadPool::ThreadPool
• dp::thread-pool

You can then use find_package():

find_package(dp::thread-pool REQUIRED)

Alternatively, you can use something like CPM which is based on CMake's Fetch_Content module.

CPMAddPackage(
    NAME thread-pool
    GITHUB_REPOSITORY DeveloperPaul123/thread-pool
    GIT_TAG #0cea9c12fb30cb677696c0dce6228594ce26171a change this to latest commit or release tag
)

Usage

Simple example:

// create a thread pool with a specified number of threads.
dp::thread_pool pool(4);

// add tasks, in this case without caring about results of individual tasks
pool.enqueue_detach([](int value) { /*...your task...*/ }, 34);
pool.enqueue_detach([](int value) { /*...your task...*/ }, 37);
pool.enqueue_detach([](int value) { /*...your task...*/ }, 38);
// and so on..

You can see other examples in the /examples folder.

Benchmarks

See the ./benchmark folder for the benchmark code. The benchmarks are set up to compare matrix multiplication using the dp::thread_pool versus std::async. A summary of the comparisons is below. Benchmarks were run using the windows-release CMake preset (see CMakePresets.json).

Machine Specs

• AMD Ryzen 7 1800X (16 X 3593 MHz CPUs)
• CPU Caches:
  • L1 Data 32 KiB (x8)
  • L1 Instruction 64 KiB (x8)
  • L2 Unified 512 KiB (x8)
  • L3 Unified 8192 KiB (x2)
• 32 GB RAM

Summary of Results

Matrix sizes are all square (MxM). Each multiplication is (MxM) * (MxM) where * refers to a matrix multiplication operation. Times recorded were the best of at least 3 runs.

Matrix Size	Number of multiplications	std::async time (ms)	dp::thread_pool time (ms)
8	25,000	77.9	65.3
64	5,000	100	65.2
256	250	295	59.2
512	75	713	60.4
1024	10	1160	55.8

Building

This project has been built with:

• Visual Studio 2022
• Clang 10.+ (via WSL on Windows)
• GCC 11.+ (vis WSL on Windows)
• CMake 3.21+

To build, run:

cmake -S . -B build
cmake --build build

Build Options

Option	Description	Default
TP_BUILD_TESTS	Turn on to build unit tests. Required for formatting build targets.	ON
TP_BUILD_EXAMPLES	Turn on to build examples	ON

Run clang-format

Use the following commands from the project's root directory to check and fix C++ and CMake source style. This requires clang-format, cmake-format and pyyaml to be installed on the current system. To use this feature you must turn on TP_BUILD_TESTS.

# view changes
cmake --build build/test --target format

# apply changes
cmake --build build/test --target fix-format

See Format.cmake for details.

Build the documentation

The documentation is automatically built and published whenever a GitHub Release is created. To manually build documentation, call the following command.

cmake -S documentation -B build/doc
cmake --build build/doc --target GenerateDocs
# view the docs
open build/doc/doxygen/html/index.html

To build the documentation locally, you will need Doxygen and Graphviz on your system.

Contributing

Contributions are very welcome. Please see [contribution guidelines for more info](CONTRIBUTING.md).

License

The project is licensed under the MIT license. See [LICENSE](LICENSE) for more details.

Author

@DeveloperPaul123