/*
 * test minimum select time
 *
 *	./prog usec [method [duration]]
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/event.h>
#include <sys/time.h>
#include <poll.h>
#include <fcntl.h>
#include <signal.h>

enum { M_SELECT =0 , M_POLL, M_USLEEP, M_NANOSLEEP, M_KQUEUE, M_KQUEUETO, M_ALARMF, M_ALARMN, M_SYSCALL };
static const char *names[] = { "select", "poll", "usleep", "nanosleep", "kqueue", "alarmf", "alarmn", "syscall" };

struct bintime tick_bt = { 0, ((uint64_t)1<<63) / 500 };

static void
sigalarm(int t)
{
}

int
main(int argc, char *argv[])
{
	struct timeval ta, tb;
	int usec = 1, total = 0, method = M_SELECT, count = 0, t, i;
    	int kq;

	if (argc > 1)
		usec = atoi(argv[1]);
	/*if (usec <= 0)
		usec = 1;
	else */if (usec > 500000)
		usec = 500000;
	if (argc > 2) {
		if (!strcmp(argv[2], "poll"))
			method = M_POLL;
		else if (!strcmp(argv[2], "usleep"))
			method = M_USLEEP;
		else if (!strcmp(argv[2], "nanosleep"))
			method = M_NANOSLEEP;
		else if (!strcmp(argv[2], "kqueue")) {
			method = M_KQUEUE;
    			kq = kqueue();
		} else if (!strcmp(argv[2], "kqueueto")) {
			method = M_KQUEUETO;
    			kq = kqueue();
		} else if (!strcmp(argv[2], "alarmf")) {
			method = M_ALARMF;
			signal(SIGALRM, sigalarm);
		} else if (!strcmp(argv[2], "alarmn")) {
			method = M_ALARMN;
			signal(SIGALRM, sigalarm);
			struct itimerval itv = {{ 0, usec }, { 0, usec }};
			setitimer(ITIMER_REAL, &itv, NULL);
		} else if (!strcmp(argv[2], "syscall"))
			method = M_SYSCALL;
	}
	if (argc > 3)
		total = atoi(argv[3]);
	if (total < 1)
		total = 1;
	else if (total > 30)
		total = 30;
	/*
	fprintf(stderr, "testing %s for %dus over %ds\n",
		names[method], usec, total);
	*/
	gettimeofday(&ta, NULL);
	for (;;) {
		for (i = 1000; i >= 0; i--) {
			if (method == M_SELECT) {
				struct timeval to = { 0, usec };
//				struct timeval to = { 0x7fffffffffffffff, 0 };
				select(0, NULL, NULL, NULL, &to);
			} else if (method == M_POLL) {
				poll(NULL, 0, (usec + 999) / 1000);
			} else if (method == M_USLEEP) {
        			usleep(usec);
	    		} else if (method == M_NANOSLEEP) {
				struct timespec ts = { 0, usec };
//				struct timespec ts = { 0x7fffffffffffffff, 0 };
				nanosleep(&ts, NULL);
			} else if (method == M_KQUEUE) {
				struct timespec ts = { 0, usec };
				struct kevent ke;
				EV_SET(&ke, 0, EVFILT_TIMER, EV_ADD, 0, (usec + 999) / 1000, NULL);
				kevent(kq, &ke, 1, NULL, 0, NULL);
				kevent(kq, NULL, 0, &ke, 1, NULL);
			} else if (method == M_KQUEUETO) {
				struct timespec ts = { 0, usec };
				struct kevent ke;
				EV_SET(&ke, 0, EVFILT_READ, EV_ADD, 0, 0, NULL);
				kevent(kq, &ke, 1, NULL, 0, NULL);
				kevent(kq, NULL, 0, &ke, 1, &ts);
			} else if (method == M_ALARMF) {
				struct itimerval itv = {{ 0, 0 }, { 0, usec }};
				setitimer(ITIMER_REAL, &itv, NULL);
				poll(NULL, 0, INFTIM);
			} else if (method == M_ALARMN) {
				poll(NULL, 0, INFTIM);
			} else {
				fcntl(0, O_NONBLOCK);
			}
			count++;
		}
		gettimeofday(&tb, NULL);
		timersub(&tb, &ta, &tb);
		if (tb.tv_sec > total)
			break;
	}
	/*
	fprintf(stderr, "%dus actually took %dus\n",
		usec, (int)(tb.tv_sec * 1000000 + tb.tv_usec) / count );
	*/
	t = ((uint64_t)tb.tv_sec * 1000000 + tb.tv_usec) * 100 / count;
	fprintf(stdout, "%d %d.%02d (%+d.%02d)\n",
	    usec, t / 100, t % 100, (t - usec * 100) / 100, (t - usec * 100) % 100);
	return 0;
}