Thread Pool

Author: Herbert Wang wang_xiaoq@126.com

中文版

Introduction

I implement this thread pool using the posix thread interfaces. PR and fork are welcome. The repository contains three source files: thread-pool.c and thread-pool.h implement the thread pool, and example.c demonstrates how to use the thread pool.

Interfaces

interface	description	arguments	return value
int thread_pool_init(int num)	initialize thread pool	the number of threads into the pool	0:success; -1: fail
int thread_pool_destroy(int wait)	destroy thread pool	0: destroy the thread pool immediately; 1: wait all the jobs in the thread pool to complete	0: success; -1: fail
int get_total_thread_num(void)	get the total number of threads in the thread pool	-	the number of threads in the thread pool
typedef void (*job_func_t)(void *arg)	the job function need to execute	arg: arguments to pass	-
int add_job_to_job_queue(job_func_t job_func, void *arg)	add job to thread pool	job_func: the job needs to execute	0: success; -1: fail
int add_thread_to_thread_queue(int num)	add threads into thread pool	the number of threads to add	0: success; -1: fail

Usage

a. Include 'thread-pool.h' into your source file.

#include "thread-pool.h"

b. Initialize the thread pool:

int ret = 0;
ret = thread_pool_init(10);    //initialize with 10 threads into thread pool

c. Add jobs into thread pool:

int ret = 0;
ret = add_job_to_job_queue(job_func, NULL);

d. Destroy the thread pool:

int ret = 0;
ret = thread_pool_destroy(1);    //wait all the jobs in the pool to complete

Demonstration

example.c into the repository is an example of how to use the thread pool.

/*
 * example.c
 * Author : Herbert <wang_xiaoq@126.com>
 * LICENSE: GPL v2
 */

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

#include "thread-pool.h"

void test(void *arg)
{
    printf("I am a job\n");
    sleep(5);
}

int main(void)
{
    int ret = 0;
    int i = 0;
    pthread_t tid = 0;

    ret = thread_pool_init(3);
    for (i = 0; i < 100; i++) {
        add_job_to_job_queue(test, NULL);
    }

    sleep(10);

    /* destroy the thread pool immediately */
    thread_pool_destroy(0);
    /* wait all the job on the jon queue to complete */
    //thread_pool_destroy(1);

    return 0;
}

I use 3 threads to initialize the thread pool, then add 100 jobs into it. Each job just print 'I am a job' and sleep 5 seconds. The main function then sleep 10 seconds and destroy the thread pool immediately. Also you can use another way to destroy, waiting all the job in the pool to complete, but this will need long time :).

The way to run example.c:

gcc example.c thread-pool.c -o example -lpthread
./example

LICENSE

GPL v2