#include <sched.h>
#include <stdlib.h>
#include <stdio.h>
 #include <sys/time.h>
#include <sys/resource.h>



void work(int i)
{
//getusage
int who= RUSAGE_SELF;
struct rusage usage;
struct rusage *p=&usage;
//==getrusage
int j;
	for(j=0;j<10000;j++)
	{

	}
	getrusage(who,p);
	printf("N = %d => %d \n",i,p->ru_stime.tv_usec*1000);

}

main(){


//time
struct timeval now;
int rc;
//==time

 struct sched_param param;
 int children[100];
 int i,j;
 int n= 100;

param.sched_priority=10;
sched_setscheduler(getpid(),SCHED_RR, &param);

for(i=0;i<n;i++)
{

	if(fork() == 0)
	{
		param.sched_priority=5;
		sched_setscheduler(getpid(),SCHED_RR, &param);
		work(i);
		return;
	}


}

//get time
gettimeofday(&now, NULL);
unsigned a= now.tv_usec;
 printf("time = %u.%06u\n",now.tv_sec, now.tv_usec);

param.sched_priority=4;
sched_setscheduler(getpid(),SCHED_RR, &param);


//get time
gettimeofday(&now, NULL);
unsigned b = now.tv_usec;
 printf("time = %u.%06u\n",now.tv_sec, now.tv_usec);

printf("Diff = 0.%u \n",b-a);

}