Thread Pools and std::async
Thread Pool is a collection of pre-created threads that can execute multiple tasks efficiently without repeatedly creating and destroying threads. It improves performance by reusing threads and managing system resources effectively.
Thread pools are a foundational pattern in concurrent programming. Instead of spawning a new thread for each task—which is costly—a thread pool keeps a fixed number of threads alive and reuses them to handle incoming work. This approach reduces overhead, improves CPU utilization, and prevents excessive thread creation.
C++ simplifies asynchronous programming with std::async, which automatically handles task execution. Depending on the launch policy, it may run a task in a new thread or defer it until needed. While not a true thread pool, std::async provides a simple and effective way to run multiple tasks concurrently and collect their results using std::future.
main.cpp
123456789101112131415161718192021222324252627#include <iostream> #include <future> #include <vector> #include <chrono> // Simulate a time-consuming computation int compute_square(int x) { std::this_thread::sleep_for(std::chrono::milliseconds(100)); return x * x; } int main() { std::vector<std::future<int>> futures; // Launch several asynchronous tasks for (int i = 1; i <= 5; ++i) futures.push_back(std::async(std::launch::async, compute_square, i)); // Retrieve and print results for (int i = 0; i < futures.size(); ++i) { int result = futures[i].get(); std::cout << "Square of " << (i + 1) << " is " << result << std::endl; } }
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Thread Pool is a collection of pre-created threads that can execute multiple tasks efficiently without repeatedly creating and destroying threads. It improves performance by reusing threads and managing system resources effectively.
Thread pools are a foundational pattern in concurrent programming. Instead of spawning a new thread for each task—which is costly—a thread pool keeps a fixed number of threads alive and reuses them to handle incoming work. This approach reduces overhead, improves CPU utilization, and prevents excessive thread creation.
C++ simplifies asynchronous programming with std::async, which automatically handles task execution. Depending on the launch policy, it may run a task in a new thread or defer it until needed. While not a true thread pool, std::async provides a simple and effective way to run multiple tasks concurrently and collect their results using std::future.
main.cpp
123456789101112131415161718192021222324252627#include <iostream> #include <future> #include <vector> #include <chrono> // Simulate a time-consuming computation int compute_square(int x) { std::this_thread::sleep_for(std::chrono::milliseconds(100)); return x * x; } int main() { std::vector<std::future<int>> futures; // Launch several asynchronous tasks for (int i = 1; i <= 5; ++i) futures.push_back(std::async(std::launch::async, compute_square, i)); // Retrieve and print results for (int i = 0; i < futures.size(); ++i) { int result = futures[i].get(); std::cout << "Square of " << (i + 1) << " is " << result << std::endl; } }
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