Linux线程调度

  1 #include <stdio.h>
  2 #include <pthread.h>
  3 #include <sched.h>
  4 #include <assert.h>
  5 
  6 static int api_get_thread_policy(pthread_attr_t *attr)
  7 {
  8     int policy = 0;
  9     int rs = 0;
 10 
 11     rs = pthread_attr_getschedpolicy(attr, &policy);
 12     assert(0 == rs);
 13 
 14     switch(policy)
 15     {
 16         case SCHED_FIFO:
 17             printf("policy = SCHED_FIFO\n");
 18             break;
 19         case SCHED_RR:
 20             printf("policy = SCHED_RR\n");
 21             break;
 22         case SCHED_OTHER:
 23             printf("policy = SCHED_OTHER\n");
 24             break;
 25         default:
 26             printf("policy = UNKNOWN\n");
 27             break;
 28     }
 29 
 30     return policy;
 31 }
 32 
 33 static void api_set_thread_policy(pthread_attr_t *attr, int policy)
 34 {
 35     int rs = 0;
 36 
 37     rs = pthread_attr_setschedpolicy(attr, policy);
 38     assert(0 == rs);
 39     (void)api_get_thread_policy(attr);
 40 }
 41 
 42 static void api_show_thread_priority(int policy)
 43 {
 44     int priority = 0;
 45 
 46     priority = sched_get_priority_max(policy);
 47     assert(-1 != priority);
 48     printf("max_priority = %d\n", priority);
 49 
 50     priority = sched_get_priority_min(policy);
 51     assert(-1 != priority);
 52     printf("min_priority = %d\n", priority);
 53 }
 54 
 55 static int api_get_thread_priority(pthread_attr_t *attr)
 56 {
 57     struct sched_param param;
 58     int rs = 0;
 59 
 60     rs = pthread_attr_getschedparam(attr, &param);
 61     assert(0 == rs);
 62     printf("priority = %d\n", param.__sched_priority);
 63 
 64     return param.sched_priority;
 65 }
 66 
 67 static void api_set_thread_priority(pthread_attr_t *attr, int priority)
 68 {
 69     struct sched_param param;
 70     int rs = 0;
 71 
 72     rs = pthread_attr_getschedparam(attr, &param);
 73     assert(0 == rs);
 74 
 75     param.__sched_priority = priority;
 76     rs = pthread_attr_setschedparam(attr, &param);
 77     assert(0 == rs);
 78 
 79     (void)api_get_thread_priority(attr);
 80 }
 81 
 82 //int api_set_policy_priority_main()
 83 int main()
 84 {
 85     pthread_attr_t attr;
 86     int rs = 0;
 87 
 88     rs = pthread_attr_init(&attr);
 89     assert(0 == rs);
 90 
 91     int policy = api_get_thread_policy(&attr);
 92 
 93     printf("Show current configuration of priofity\n");
 94     api_show_thread_priority(policy);
 95 
 96     printf("Show SCHED_FIFO of priority\n");
 97     api_show_thread_priority(SCHED_FIFO);
 98 
 99     printf("Show SCHED_RR of priority\n");
100     api_show_thread_priority(SCHED_RR);
101 
102     printf("Show priority of current thread\n");
103     int priority = api_get_thread_priority(&attr);
104 
105     printf("Set SCHED_FIFO policy\n");
106     api_set_thread_policy(&attr, SCHED_FIFO);
107 
108     printf("Set SCHED_RR policy\n");
109     api_set_thread_policy(&attr, SCHED_RR);
110 
111     printf("Restore current policy\n");
112     api_set_thread_policy(&attr, policy);
113 
114     printf("Restore current priority\n");
115     api_set_thread_priority(&attr, priority);
116 
117     rs = pthread_attr_destroy(&attr);
118     assert(0 == rs);
119 
120     return 0;
121 }