#include <sched.h>
#include <unistd.h>
#include <stdio.h>
#include <assert.h>

#define NUM_THREAD	4
#define STACK_SIZE	4000
#define	LOOP_STOP	1000

/* stacks */
void* stack[NUM_THREAD][STACK_SIZE];

/* log thread pids */
int pids[NUM_THREAD];

void report_proc_time(int pid)
{
	char fname[80];
	FILE* procf;
	
	char cmd[80];
	unsigned long utime, stime;

	sprintf(fname, "/proc/%d/stat", pid);
	procf = fopen(fname, "r");
	if (procf == NULL) {
		printf("failed to open file %s\n", fname);
		assert(0 ==1);
	}

	fscanf(procf, "%d %s %*c %*d %*d %*d %*d %*d %*lu %*lu %*lu %*lu %*lu %lu %lu", &pid, cmd, &utime, &stime);
	printf("pid=%d, cmd: %s, time(ms): %lu, utime(ms): %lu, stime(ms): %lu\n", pid, cmd, (utime+stime)*10, utime*10, stime*10);

	fclose(procf);
}

void report_time(void)
{
	int i;
	printf("-----------------------------------------\n");
	for (i=0; i< NUM_THREAD; i++)
		report_proc_time(pids[i]);
}

int loop (void *arg)
{
	/* determine number of clones */
	int i;
	int x=(int)arg;
	pids[x] = getpid();

	/*closed loop */
	for(;;) {
		for (i=0; i<LOOP_STOP; i++)
			printf("%d\n", x);
		// if (x == 0) report_time();
	}
};

main() 
{
	int i;
	for (i=1; i< NUM_THREAD; i++) 
		__clone(loop, stack[i]+4000,CLONE_VM, i);

	loop(0);
};