How Can C 11 Thread Pools Improve Task Management and Reduce Overhead?

Thread Pooling in C 11

Challenge:
Creating and managing threads can be expensive, especially if repeated for each task. How can we create a thread pool that allows us to send multiple tasks to a pool of threads, avoiding the overhead of thread creation?

Answer:

Implementing a thread pool in C 11 involves creating a class that manages a collection of threads that can be reused to execute tasks. Here's a breakdown of the key aspects:

Implementing the ThreadPool Class:

The ThreadPool class defines the interface for creating, managing, and stopping a thread pool.

1. ThreadPool::Start:
Initializes the thread pool by creating the specified number of threads. These threads will execute an infinite loop, waiting for tasks.

2. ThreadPool::ThreadLoop:
The infinite loop that each thread in the pool executes. It continuously checks for new tasks, executes them, and repeats until termination is signaled.

3. ThreadPool::QueueJob:
Adds a task to the thread pool queue. The task is a function object that defines the work to be done.

4. ThreadPool::busy:
Checks if the thread pool has any pending tasks.

5. ThreadPool::Stop:
Terminates the thread pool, waiting for all threads to finish their current tasks.

Integrating the ThreadPool:

Once the ThreadPool class is defined, you can use it as follows:

thread_pool->QueueJob([] { /* ... */ });

Example:

std::vector<std::thread> workers;
int total = 4;
int arr[4] = {0};

void each_thread_does(int i) {
  arr[i] += 2;
}

int main() {
  // ThreadPool Example
  ThreadPool thread_pool;
  thread_pool.Start();

  for (int i = 0; i < 8; ++i) {
    for (int j = 0; j < 4; ++j) {
      thread_pool.QueueJob(std::bind(each_thread_does, j));
    }
  }

  // Wait for the thread pool to complete
  while (thread_pool.busy()) {}
  thread_pool.Stop();

  arr[4] = std::min_element(arr, arr + 4);
  return 0;
}

This example demonstrates how to create a thread pool using the provided class and submit multiple tasks to the pool without the need for repetitive thread creation and deletion.

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