#include <u.h>
#include <libc.h>
#include <fcall.h>

/* How long does it take to stat a file? Minimum file system latency. */

void
usage(void)
{
	fprint(2, "usage: %s [-f file] [-i millisecs]\n", argv0);
	exits("usage");
}

void
main(int argc, char **argv)
{
	float interval = 0;
	vlong before, after, diff;
	char* file = ".";
	uchar buf[STATMAX];

	ARGBEGIN {
	case 'f':
		file = EARGF(usage());
		break;
	case 'i':
		interval = atof(EARGF(usage()));
		if(interval < 0)
			usage();
		break;
	default:
		usage();
		break;
	} ARGEND;

	do {
		before = nsec();
		stat(file, buf, sizeof(buf));
		after = nsec();
		diff = after-before;
		print("%s	%,lld µs\n", file, diff);
		sleep((int)(interval*1000));
	} while(interval);
	exits(nil);
}