设置 线程优先级

参考网上代码写了一段代码, :)

void setthreadhighpriority(pthread_attr_t* attr)
{
    struct sched_param sched;
    int policy;
    int minp;
    int maxp;
    int priority, inher;
    int toset;
    int ret;

    if(0 != getuid())
    {
        return;
    }

    ret = pthread_attr_getinheritsched(attr, &inher);
    if (ret!=0 )
    {
        printf("pthread_attr_getinheritschedn%sn", strerror(ret));
        return;
    }

    if (inher == PTHREAD_EXPLICIT_SCHED)
    {
        printf("PTHREAD_EXPLICIT_SCHEDn");
    }
       else if (inher == PTHREAD_INHERIT_SCHED)
    {
        inher = PTHREAD_EXPLICIT_SCHED;
    }

    ret = pthread_attr_setinheritsched(attr, inher);
    if (ret!=0)
    {
        printf("pthread_attr_setinheritschedn%sn", strerror(ret));
        return;
    }

    ret = pthread_attr_getschedpolicy(attr, &policy);
    if(ret)
    {
        printf(" line[%d] ret %dn ", __LINE__, ret);
        return;
    }

    if(policy == SCHED_OTHER)
    {
        ret = pthread_attr_setschedpolicy(attr, SCHED_RR);
        if(ret)
        {
            printf(" line[%d] ret %dn ", __LINE__, ret);
            return;
        }

        ret = pthread_attr_getschedpolicy(attr, &policy);
        if(ret)
        {
            printf(" line[%d] ret %dn ", __LINE__, ret);
            return;
        }

        /*
        switch (policy)
        {
            case SCHED_FIFO:
                printf("policy= SCHED_FIFOn") ;
                break ;
            case SCHED_RR:
                printf("policy= SCHED_RRn") ;
                break ;
            case SCHED_OTHER:
                printf("policy=SCHED_OTHERn") ;
                break ;
            default :
                printf ( "policy=UNKNOWNn" ) ;
                break ;
        }
        */
    }

    maxp = sched_get_priority_max(policy);
    if(maxp < 0)
    {
        printf(" line[%d] ret %dn ", __LINE__, maxp);
        return;
    }
    minp = sched_get_priority_min(policy);
    if(minp < 0)
    {
        printf(" line[%d] ret %dn ", __LINE__, minp);
        return;
    }

    ret = pthread_attr_getschedparam(attr, &sched);
    if(ret)
    {
        printf(" line[%d] ret %dn ", __LINE__, ret);
        return;
    }

    priority = sched.__sched_priority;
    if(priority == 0)
    {
        priority = 30;
    }

    if(priority > maxp || priority < minp)
    {
        printf(" priority not setn");
        return;
    }

    toset = priority + (maxp - priority)*6/10;
    sched.__sched_priority = toset;
    ret = pthread_attr_setschedparam(attr, &sched);
    if(ret)
    {
        printf(" line[%d] ret %dn ", __LINE__, ret);
        return;
    }
    ret = pthread_attr_getschedparam(attr, &sched);
    if(ret)
    {
        printf(" line[%d] ret %dn ", __LINE__, ret);
        return;
    }

    printf("before:%d now:%dn", priority, sched.__sched_priority);
    return ;
}