对pthreads

Question

我试图在Linux中使用

设置低优先级[priority = 10]

  

pthread_setschedparam()

然而，我从函数中得到的可接受值 sched_get_priority_{min|max}() 为0-99。

如果我给1，我优先考虑-2 如果我给90，我优先考虑-90 但我希望获得优先权10。

代码如下。有没有办法为线程分配低优先级。
[注意 - 我还尝试了 setpriority ，但这在我的情况下不起作用，因为我需要从主线程中分配优先级]

#include <pthread.h>
#include <errno.h>
#include <string.h>

void *print_message_function( void *ptr );

main()
{
     pthread_t thread1, thread2;
     const char *message1 = "Thread 1";
     const char *message2 = "Thread 2";
     int  iret1, iret2;

     struct sched_param sch_params;
     //sch_params.sched_priority = 5;
     sch_params.sched_priority = 10; 

    /* Create independent threads each of which will execute function */

     iret1 = pthread_create( &thread1, NULL, print_message_function, (void*) message1);
     if(iret1)
     {   
         printf("Error - pthread_create() return code: %d\n",iret1);
         exit(EXIT_FAILURE);
     }   
     if(pthread_setschedparam(thread1, SCHED_RR, &sch_params)) {
        printf( "Failed to set thread's priority : %s \n",strerror(errno));
     } else {
        printf( "thread priority is set properly: \n");
     }   

     pthread_join( thread1, NULL);
     exit(EXIT_SUCCESS);
}

void *print_message_function( void *ptr )
{
     char *message;
     message = (char *) ptr;
     while (1) {
        printf("%s \n", message);
        sleep(1);
     }   
}