我有两个线程,线程 1 和线程 2。我先创建thread1,然后创建thread2。但是thread2是先调度的。我想在线程 2 之前安排线程 1。我将线程 1 的策略更改为 SCHED_FIFO,将线程 2 的策略更改为 SCHED_RR。即使在这个 thread2 之前安排之后。然后我将两个线程声明为 SCHED_FIFO,并分配了不同的优先级,如下面的程序所示。尽管没有变化。我想检查线程中的策略,因为它返回 0。线程策略似乎没有改变。
请帮助我解决这个问题。
#include <stdio.h>
#include <pthread.h>
#include <sys/types.h>
pthread_t thread1, thread2;
void *
thread1_func (void *i)
{
struct sched_param p3;
int i1 = 0;
int policy;
i = pthread_getschedparam (thread1, (int *) &policy, &p3);
printf ("in thread1 with priority :%u policy: %u\n", p3.sched_priority,
policy);
}
void *
thread2_func (void *i)
{
struct sched_param p3;
int i1 = 0;
int policy;
i1 = pthread_getschedparam (thread1, (int *) &policy, &p3);
printf ("in thread2 with priority :%u and policy %u\n", p3.sched_priority,
policy);
}
int
main ()
{
struct sched_param p1, p2;
pthread_attr_t attr1, attr2;
pthread_attr_init (&attr1);
pthread_attr_init (&attr2);
pthread_attr_setinheritsched (&attr1, PTHREAD_INHERIT_SCHED);
pthread_attr_setschedpolicy (&attr1, SCHED_FIFO);
p1.sched_priority = 20;
pthread_attr_setschedparam (&attr1, &p1);
//pthread_attr_setschedpolicy(&attr2, SCHED_RR);
//pthread_attr_setschedpolicy(&attr2, SCHED_RR);
/* tried to set the policY of thread1 as "FIFO" and thread2 as "RR" to make thread1 run before thread2 but it is not working*/
//pthread_attr_setschedpolicy(&attr2, SCHED_FIFO);
//p2.sched_priority = 10;
//pthread_attr_setschedparam(&attr2,&p2);
pthread_create (&thread1, &attr1, (void *) thread1_func, NULL);
pthread_create (&thread2, NULL, (void *) thread2_func, NULL);
/*p1.sched_priority = 0;
int policy=1;
struct sched_param p4;
pthread_setschedparam(thread1,(int *)&policy,&p4);
pthread_getschedparam(thread1,&policy,&p4);
printf("the pri::::thread1 %d policy %d\n",p4.sched_priority,policy);
*/
pthread_join (thread1, NULL);
pthread_join (thread2, NULL);
return 0;
}
最佳答案
问题是:
pthread_attr_setinheritsched (&attr1, PTHREAD_INHERIT_SCHED);
The following values may be specified in inheritsched: PTHREAD_INHERIT_SCHED Threads that are created using attr inherit scheduling attributes from the creating thread; the scheduling attributes in attr are ignored. PTHREAD_EXPLICIT_SCHED Threads that are created using attr take their scheduling attributes from the values specified by the attributes object.
参见 http://man7.org/linux/man-pages/man3/pthread_attr_setinheritsched.3.html
关于c - 无法将线程策略更改为 SCHED_FIFO,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31404770/