基于状态的1对N无锁多线程程序的一般结构

总结了下，通过状态来实现线程工作切换的1对N多线程模型(1个调度，多个工作的模型)，一般的代码结构大致如下,与大家分享下，希望听到更好的建议和想法。

 

首先是状态数据结构

enum thread_status
{
        status_free = 1,
        status_ready = 2,
        status_running = 3,
        status_over = 4,
        status_dead = 5
};

其次是线程体结构(这个结构作为pthread_create时的参数)

typedef struct
{
        pthread_t thread; //thread
        unsigned char status; //status
        unsigned int index;
}thread_t;

最后是线程体(thread_func的一般代码结构)

初始化：

for ( index = 0; index < pp->thread_num; index++)
        {
                pp->thread_list[index].status = status_free;
                pp->thread_list[index].index = index;
                //create thread
                if (pthread_create (
                        &(pp->thread_list[index].thread), //thread entry
                        0, //attribute
                        app_thread, //start function
                        pp->thread_list + index))//parameter passed to thread function
                {
                        printf ("create thread for thread %u failed\n", index);
                        return -1;
                }
        }

运行时:

 

void * app_thread(void*data)
{
    thread_t * pt = (thread_t*)data;
    pthread_detach (pthread_self());

    while (pt->status != status_dead)
    {
        //when it is free, do nothing...
        if (pt->status == status_free)
        {
            printf ("thread %u is free now\n", pt->index);
            sleep (1);
            continue;
        }

        //ready means it ought to do something,free -> ready is changed by outter thread
        //but not itself
        if (pt->status == status_ready)
        {
            printf ("thread_%d: ready....go !!!\n");
            pt->status = status_running;
            continue;
        }

        //running, do something
        if (pt->status == status_running)
        {
            while (do_some_thing())
            {
                sleep (1);
            }
            //when everything is done, change status to status_over myself
            pt->status = status_over;
            continue;
        }

        //when i am running over, just waitting someone else to change the
        //status to status_ready to run new tasks or status_dead to exit
        if (pt->status == status_over)
        {
            sleep(1);
        }

        //it's time to say goodbye...
        if (pt->status == status_dead)
        {
            printf ("good luck, i'm now exiting..bye\n");
            break;
        }
    }
    pthread_exit (0);
}