sched_dead_test.c

#include <sched.h>
#include <linux/sched.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/syscall.h> 
#include <inttypes.h>
#include <sched.h>
#include <time.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

struct sched_attr {
    uint32_t size;
    uint32_t sched_policy;
    uint64_t sched_flags;

    /* SCHED_NORMAL, SCHED_BATCH */
    int32_t sched_nice;
    /* SCHED_FIFO, SCHED_RR */
    uint32_t sched_priority;
    /* SCHED_DEADLINE */
    uint64_t sched_runtime;
    uint64_t sched_deadline;
    uint64_t sched_period;
};

#ifndef SCHED_DEADLINE
#define SCHED_DEADLINE          6
#endif

static int
sched_setattr(pid_t pid, const struct sched_attr *attr, unsigned int flags)
{
    return syscall(__NR_sched_setattr, pid, attr, flags);
}

static int
sched_getattr(pid_t pid, const struct sched_attr *attr, unsigned int size, unsigned int flags)
{
    return syscall(__NR_sched_getattr, pid, attr, flags);
}

int main(int argc, char * argv[]) {
    
    if ( argc != 2 ) {
        printf("usage: sched_dead_test <pid>\n");
        return 0;
    }

    struct sched_param param;
    struct sched_attr attr;
    int ret = 0;
    pid_t pid = (pid_t)(atoi(argv[1]));

    ret = sched_getparam(pid,&param);

    printf("running sched_dead_test for %ld\n",pid);

    if (ret)
        printf("1ret=%d (%s)\n",ret,strerror(errno));

    ret = sched_getattr(pid,&attr,sizeof(struct sched_attr),0);

    if (ret)
        printf("2ret=%d (%s)\n",ret,strerror(errno));

    ret = 0;

    attr.sched_policy = SCHED_DEADLINE;
    attr.sched_runtime =    5000000;  //5ms
    attr.sched_deadline =   50000000; //50ms
    attr.sched_period =     50000000; //50ms

    //sched_setparam((pid_t)(atoi(argv[0])),&param);
    ret = sched_setattr((pid_t)(atoi(argv[1])), &attr, 0);

    if (ret)
        printf("3ret=%d (%s)\n",ret,strerror(errno));

    ret = 0;
    //int sched_setscheduler(pid_t pid, int policy, const struct sched_param *param);
    ret = sched_setscheduler((pid_t)(atoi(argv[1])),SCHED_DEADLINE,&param);

    if (ret)
        printf("4ret=%d (%s)\n",ret,strerror(errno));

    //int sched_setattr(pid_t pid, const struct sched_attr *attr, unsigned int flags);

    return 0;

}