#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>

static unsigned long long gett(void)
{
	struct timeval tv;
	if (gettimeofday(&tv, NULL)) perror("gettimeofday"), exit(1);
	return (unsigned long long)tv.tv_sec * 1000000 + tv.tv_usec;
}

static void rd(unsigned long long *u1, unsigned long long *u2, unsigned long long *u3)
{
	unsigned long long us, ni, sy, id, iow, irq, sirq;
	FILE *f;
	if (!(f = fopen("/proc/stat", "r"))) perror("fopen"), exit(1);
	if (fscanf(f, "cpu %llu %llu %llu %llu %llu %llu %llu", &us, &ni, &sy, &id, &iow, &irq, &sirq) != 7) fprintf(stderr, "bad file format\n"), exit(1);
	if (fclose(f)) perror("fclose"), exit(1);

	*u1 = us + ni + sy;
	*u2 = id + iow;
	*u3 = irq + sirq;
}

static unsigned long long u0, u1, u2, u3;
static unsigned long long v0, v1, v2, v3;

void sig(int __attribute__((unused)) signo)
{
	rd(&v1, &v2, &v3);
	v0 = gett();
	printf("busy: %f%%\n", (v1 - u1) / 56. / 100. / ((v0 - u0) / 1000000.) * 100.);
	printf("idle: %f%%\n", (v2 - u2) / 56. / 100. / ((v0 - u0) / 1000000.) * 100.);
	printf("irq:  %f%%\n", (v3 - u3) / 56. / 100. / ((v0 - u0) / 1000000.) * 100.);
}

int main(void)
{
	rd(&u1, &u2, &u3);
	u0 = gett();
	signal(SIGINT, sig);
	pause();
	return 0;
}