线程调度

rt_mutex教程线程优先级高的没有delay，怎么会运行线程优先级低的

发布于 2022-03-09 11:14:50 浏览：1297 订阅该版

```c
static void rt_thread_entry1(void *parameter)
{
      while(1)
      {
          /* 线程1获取到互斥量后，先后对number1、number2进行加1操作，然后释放互斥量 */
          rt_mutex_take(dynamic_mutex, RT_WAITING_FOREVER);          
          number1++;
          rt_thread_mdelay(10);
          number2++;          
          rt_mutex_release(dynamic_mutex);
       }	    
}

ALIGN(RT_ALIGN_SIZE)
static char thread2_stack[1024];
static struct rt_thread thread2;
static void rt_thread_entry2(void *parameter)
{     
      while(1)
      {
          /* 线程2获取到互斥量后，检查number1、number2的值是否相同，相同则表示mutex起到了锁的作用 */
          rt_mutex_take(dynamic_mutex, RT_WAITING_FOREVER);
          if(number1 != number2)
          {
            rt_kprintf("not protect.number1 = %d, mumber2 = %d \n",number1 ,number2);
          }
          else
          {
            rt_kprintf("mutex protect ,number1 = mumber2 is %d\n",number1);            
          }
          
           number1++;
           number2++;
           rt_mutex_release(dynamic_mutex);
          
          if(number1 >=50)
              return;      
      }	  
}

/* 互斥量示例的初始化 */
int mutex_sample(void)
{
    /* 创建一个动态互斥量 */
    dynamic_mutex = rt_mutex_create("dmutex", RT_IPC_FLAG_FIFO);
    if (dynamic_mutex == RT_NULL)
    {
        rt_kprintf("create dynamic mutex failed.\n");
        return -1;
    }

rt_thread_init(&thread1,
                   "thread1",
                   rt_thread_entry1,
                   RT_NULL,
                   &thread1_stack[0],
                   sizeof(thread1_stack), 
                   THREAD_PRIORITY, THREAD_TIMESLICE);
    rt_thread_startup(&thread1);
    
    rt_thread_init(&thread2,
                   "thread2",
                   rt_thread_entry2,
                   RT_NULL,
                   &thread2_stack[0],
                   sizeof(thread2_stack), 
                   THREAD_PRIORITY-1, THREAD_TIMESLICE);
    rt_thread_startup(&thread2);
    return 0;
}
```
个线程2都没有 rt_thread_mdelay，线程1是怎么会运行，线程2的优先级高，一开始看官网教程的时候都说，线程高的优先级，不放开cpu，是不会运行线程优先低的，现在看互斥锁又矛盾了。