线程调度的学习例子

时间：2022-07-24 15:41:20

 

设置线程优先级的例子

  1 #include <stdio.h>
  2 #include <unistd.h>
  3 #include <stdlib.h>
  4 #include <pthread.h>
  5 
  6 void Thread1()
  7 {
  8   sleep(1);
  9   int i,j;
 10   int policy;
 11   struct sched_param param;
 12   pthread_getschedparam(pthread_self(),&policy,&param);
 13   if(policy == SCHED_OTHER)
 14     printf("SCHED_OTHER\n");
 15   if(policy == SCHED_RR);
 16     printf("SCHED_RR 1 \n");
 17   if(policy==SCHED_FIFO)
 18     printf("SCHED_FIFO\n");
 19 
 20   for(i=1;i<10;i++)
 21   {
 22     for(j=1;j<5000000;j++)
 23     {
 24     }
 25     printf("thread 1\n");
 26   }
 27   printf("Pthread 1 exit\n");
 28 }
 29 
 30 void Thread2()
 31 {
 32   sleep(1);
 33   int i,j,m;
 34   int policy;
 35   struct sched_param param;
 36 pthread_getschedparam(pthread_self(),&policy,&param);
 37  if(policy == SCHED_OTHER)
 38     printf("SCHED_OTHER\n");
 39   if(policy == SCHED_RR);
 40   printf("SCHED_RR\n");
 41   if(policy==SCHED_FIFO)
 42     printf("SCHED_FIFO\n");
 43 
 44   for(i=1;i<10;i++)
 45   {
 46     for(j=1;j<5000000;j++)
 47     {
 48      
 49     }
 50     printf("thread 2\n");
 51   }
 52   printf("Pthread 2 exit\n");
 53 }
 54 
 55 void Thread3()
 56 {
 57   sleep(1);
 58   int i,j;
 59   int policy;
 60   struct sched_param param;
 61 pthread_getschedparam(pthread_self(),&policy,&param);
 62  if(policy == SCHED_OTHER)
 63     printf("SCHED_OTHER\n");
 64   if(policy == SCHED_RR)
 65     printf("SCHED_RR \n");
 66   if(policy==SCHED_FIFO)
 67     printf("SCHED_FIFO\n");
 68 
 69   for(i=1;i<10;i++)
 70   {
 71     for(j=1;j<5000000;j++)
 72     {
 73     }
 74     printf("thread 3\n");
 75   }
 76   printf("Pthread 3 exit\n");
 77 }
 78 
 79 int main()
 80 {
 81   int i;
 82   i = getuid();
 83   if(i==0)
 84     printf("The current user is root\n");
 85   else
 86     printf("The current user is not root\n");
 87 
 88   pthread_t ppid1,ppid2,ppid3;
 89   struct sched_param param;
 90 
 91   pthread_attr_t attr,attr1,attr2;
 92   
 93   pthread_attr_init(&attr);
 94   pthread_attr_init(&attr1);
 95   pthread_attr_init(&attr2);
 96   param.sched_priority = 51;
 97  pthread_attr_setschedpolicy(&attr2,SCHED_RR);
 98  pthread_attr_setschedparam(&attr2,&param);
 99  pthread_attr_setinheritsched(&attr2,PTHREAD_EXPLICIT_SCHED);//要使优先级其作用必须要有这句话
100 
101  param.sched_priority = 21;
102  pthread_attr_setschedpolicy(&attr1,SCHED_RR);
103  pthread_attr_setschedparam(&attr1,&param);
104  pthread_attr_setinheritsched(&attr1,PTHREAD_EXPLICIT_SCHED);
105  
106  pthread_create(&ppid3,&attr,(void *)Thread3,NULL);
107  pthread_create(&ppid2,&attr1,(void *)Thread2,NULL);
108  pthread_create(&ppid1,&attr2,(void *)Thread1,NULL); //线程1的优先级大于线程2
109  
110  pthread_join(ppid3,NULL);
111  pthread_join(ppid2,NULL);
112  pthread_join(ppid1,NULL);
113  pthread_attr_destroy(&attr2);
114  pthread_attr_destroy(&attr1);
115  pthread_attr_destroy(&attr);
116  return 0;
117 }

 

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