#include "perf.h"
#include <assert.h>
#include <errno.h>
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <time.h>
#include "perf.h"

static double dummy3(double x, int iters);

long long get_real_usec(void)
{
	struct timespec ts;
	clock_gettime(CLOCK_REALTIME, &ts);
	return ((long long) ts.tv_sec * 1000000) + ((long long) ts.tv_nsec
			/ 1000);
}

#define NUM_FLOPS 20000000

int main(int argc, char **argv)
{
	struct perf_event_attr event_attr;
	int iters = NUM_FLOPS;
	double x = 1.1, y;
	long long t1, t2;

	t2 = 1000000; /* Target: 1,000,000 usec */

	/* Measure one run */
	t1 = get_real_usec();
	y = dummy3(x, iters);
	t1 = get_real_usec() - t1;

	if (t2 > t1) /* Scale up execution time to match t2 */
		iters = iters * (int) (t2 / t1);

	x = 1.0;

	memset(&event_attr, 0, sizeof(struct perf_event_attr));
	event_attr.read_format = PERF_FORMAT_GROUP | PERF_FORMAT_ID
			| PERF_FORMAT_TOTAL_TIME_RUNNING
			| PERF_FORMAT_TOTAL_TIME_ENABLED;
	event_attr.disabled = 1;
	event_attr.type = PERF_TYPE_HARDWARE;
	event_attr.config = PERF_COUNT_HW_CPU_CYCLES;

	/* count this thread, make this the group leader */
	int fd = sys_perf_event_open(&event_attr, 0, -1, -1, 0);
	if (fd == -1) {
		printf("sys_perf_event_open failed: %s\n", strerror(errno));
		exit(1);
	}

	int ret = ioctl(fd, PERF_EVENT_IOC_ENABLE, NULL);
	if (ret == -1) {
		printf("enable failed: %s\n", strerror(errno));
		exit(1);
	}
	y = dummy3(x, iters);
#ifdef DO_DISABLE
	ret = ioctl(fd, PERF_EVENT_IOC_DISABLE, NULL);
	if (ret == -1) {
		printf("disable failed: %s\n", strerror(errno));
		exit (1);
	}
#endif

	uint64_t buffer[5];
	int cnt;
	cnt = read(fd, buffer, sizeof(buffer));
	if (cnt == -1) {
		printf("read failed: %s\n", strerror(errno));
	}
	int i;
	for (i = 0; i < 5; i++) {
		printf("[%d] = %llx\n", i, buffer[i]);
	}

#define TIME_ENABLED_IDX 1
#define TIME_RUNNING_IDX 2

	if (!buffer[TIME_ENABLED_IDX] || !buffer[TIME_RUNNING_IDX]) {
		printf("test failed!\n");
		exit(1);
	} else {
		printf("test passed!\n");
		exit(0);
	}
}

static double dummy3(double x, int iters)
{
	int i;
	double w, y, z, a, b, c, d, e, f, g, h;
	double one;
	one = 1.0;
	w = x;
	y = x;
	z = x;
	a = x;
	b = x;
	c = x;
	d = x;
	e = x;
	f = x;
	g = x;
	h = x;
	for (i = 1; i <= iters; i++) {
		w = w * 1.000000000001 + one;
		y = y * 1.000000000002 + one;
		z = z * 1.000000000003 + one;
		a = a * 1.000000000004 + one;
		b = b * 1.000000000005 + one;
		c = c * 0.999999999999 + one;
		d = d * 0.999999999998 + one;
		e = e * 0.999999999997 + one;
		f = f * 0.999999999996 + one;
		g = h * 0.999999999995 + one;
		h = h * 1.000000000006 + one;
	}
	return 2.0 * (a + b + c + d + e + f + w + x + y + z + g + h);
}