/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h> typedef uvlong u64int; #define TWID64	((u64int)~(u64int)0)  u64intunittoull(char *s){	char *es;	u64int n; 	if(s == nil)		return TWID64;	n = strtoul(s, &es, 0);	if(*es == 'k' || *es == 'K'){		n *= 1024;		es++;	}else if(*es == 'm' || *es == 'M'){		n *= 1024*1024;		es++;	}else if(*es == 'g' || *es == 'G'){		n *= 1024*1024*1024;		es++;	}	if(*es != '\0')		return TWID64;	return n;} voidmain(int argc, char *argv[]){	int fd, i;	int n = 1000, m;	int s = 1;	double *t, t0, t1;	uchar *buf;		double a, d, max, min; 	m = OREAD;	ARGBEGIN{	case 'n':		n = atoi(ARGF());		break;	case 's':		s = unittoull(ARGF());		if(s < 1 || s > 1024*1024)			sysfatal("bad size");		break;	case 'r':		m = OREAD;		break;	case 'w':		m = OWRITE;		break;	}ARGEND 	fd = 0;	if(argc == 1){		fd = open(argv[0], m);		if(fd < 0)			sysfatal("could not open file: %s: %r", argv[0]);	} 	buf = malloc(s);	t = malloc(n*sizeof(double));		t0 = nsec();	for(i=0; i<n; i++){		if(m == OREAD){			if(pread(fd, buf, s, 0) < s)				sysfatal("bad read: %r");		}else{			if(pwrite(fd, buf, s, 0) < s)				sysfatal("bad write: %r");		}		t1 = nsec();		t[i] = (t1 - t0)*1e-3;		t0 = t1;	} 	a = 0.;	d = 0.;	max = 0.;	min = 1e12; 	for(i=0; i<n; i++){		a += t[i];		if(max < t[i])			max = t[i];		if(min > t[i])			min = t[i];	} 	a /= n;		for(i=0; i<n; i++)		d += (a - t[i]) * (a - t[i]);	d /= n;	d = sqrt(d); 	print("avg = %.0fµs min = %.0fµs max = %.0fµs dev = %.0fµs\n", a, min, max, d); 	exits(0);}