baotonglu/Thread-Pool

This is a simple thread pool with some enhanced features such as "wait_for_task "

Thread-Pool

This is a simple thread pool implementation that has some enhanced features such as "wait_for_task ".

Feature

You can specifiy the number of threads of the pool and submit your task to the pool. Specifically, You may refer to this page to get a full understanding.

Example of Usage

The repo has a static library named libpool.a, you can directly add this lib to your own code. An example of usage is listed below:

1. To use the ThreadPool class you create, a user would create a subclass of Task that implements the Run() method that performs an operation they want to add to the queue of operations to do:

class ComputeSumTask : public Task {
public:
    ComputeSumTask(int *sum_destination, int *array_to_sum, int array_size) {
        this->sum_destination = sum_destination;
        this->array_to_sum = array_to_sum;
        this->array_size = array_size;
    }

    void Run() {
        int sum = 0;
        for (int i = 0; i < this->array_size; ++i) {
            sum += this->array_to_sum[i];
        }
        this->sum_destination = sum;
    }
        
    int *sum_destination,
    int *array_to_sum;
    int array_size; 
};

2. Notice that the Task subclass can (and typically would) contain member variables. Then, submit a bunch of instances of this class for each thing they wanted to do in parallel

int arrayA[ARRAY_SIZE], arrayB[ARRAY_SIZE];
int sum_of_A, sum_of_B;
ThreadPool pool(num_threads);
    
pool.SubmitTask("sum arrayA", new ComputeSumTask(&sum_of_A, arrayA, ARRAY_SIZE));
pool.SubmitTask("sum arrayB", new ComputeSumTask(&sum_of_B, arrayB, ARRAY_SIZE));

3. Finally wait for the tasks to complete before stopping the thread pool(but this step is optional):

pool.WaitForTask("sum arrayA");
pool.WaitForTask("sum arrayB");

pool.Stop();

About the Source Code

Some knowledge about pthread: before invoking pthread_cond_signal, make sure to have the lock held. This ensures that we don't accidentally introduce a race condition into our code.

Disclaimer

This library is just for study. Full correctness is not guranteed.