xref: /freebsd/usr.sbin/iostat/iostat.c (revision a3cf0ef5a295c885c895fabfd56470c0d1db322d)
1 /*
2  * Copyright (c) 1997, 1998, 2000, 2001  Kenneth D. Merry
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 /*
31  * Parts of this program are derived from the original FreeBSD iostat
32  * program:
33  */
34 /*-
35  * Copyright (c) 1986, 1991, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. All advertising materials mentioning features or use of this software
47  *    must display the following acknowledgement:
48  *	This product includes software developed by the University of
49  *	California, Berkeley and its contributors.
50  * 4. Neither the name of the University nor the names of its contributors
51  *    may be used to endorse or promote products derived from this software
52  *    without specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64  * SUCH DAMAGE.
65  */
66 /*
67  * Ideas for the new iostat statistics output modes taken from the NetBSD
68  * version of iostat:
69  */
70 /*
71  * Copyright (c) 1996 John M. Vinopal
72  * All rights reserved.
73  *
74  * Redistribution and use in source and binary forms, with or without
75  * modification, are permitted provided that the following conditions
76  * are met:
77  * 1. Redistributions of source code must retain the above copyright
78  *    notice, this list of conditions and the following disclaimer.
79  * 2. Redistributions in binary form must reproduce the above copyright
80  *    notice, this list of conditions and the following disclaimer in the
81  *    documentation and/or other materials provided with the distribution.
82  * 3. All advertising materials mentioning features or use of this software
83  *    must display the following acknowledgement:
84  *      This product includes software developed for the NetBSD Project
85  *      by John M. Vinopal.
86  * 4. The name of the author may not be used to endorse or promote products
87  *    derived from this software without specific prior written permission.
88  *
89  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
90  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
91  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
92  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
93  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
94  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
95  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
96  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
97  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
98  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
99  * SUCH DAMAGE.
100  */
101 
102 
103 #include <sys/param.h>
104 #include <sys/errno.h>
105 #include <sys/resource.h>
106 #include <sys/sysctl.h>
107 
108 #include <err.h>
109 #include <ctype.h>
110 #include <fcntl.h>
111 #include <kvm.h>
112 #include <nlist.h>
113 #include <stdio.h>
114 #include <stdlib.h>
115 #include <string.h>
116 #include <termios.h>
117 #include <unistd.h>
118 #include <limits.h>
119 #include <devstat.h>
120 #include <math.h>
121 
122 struct nlist namelist[] = {
123 #define X_TK_NIN	0
124 	{ "_tk_nin" },
125 #define X_TK_NOUT	1
126 	{ "_tk_nout" },
127 #define X_BOOTTIME	2
128 	{ "_boottime" },
129 #define X_END		2
130 	{ NULL },
131 };
132 
133 #define	IOSTAT_DEFAULT_ROWS	20	/* Traditional default `wrows' */
134 
135 struct statinfo cur, last;
136 int num_devices;
137 struct device_selection *dev_select;
138 int maxshowdevs;
139 volatile sig_atomic_t headercount;
140 volatile sig_atomic_t wresized;		/* Tty resized, when non-zero. */
141 unsigned short wrows;			/* Current number of tty rows. */
142 int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0;
143 int xflag = 0, zflag = 0;
144 
145 /* local function declarations */
146 static void usage(void);
147 static void needhdr(int signo);
148 static void needresize(int signo);
149 static void doresize(void);
150 static void phdr(void);
151 static void devstats(int perf_select, long double etime, int havelast);
152 static void cpustats(void);
153 static int readvar(kvm_t *kd, const char *name, int nlid, void *ptr,
154 		   size_t len);
155 
156 static void
157 usage(void)
158 {
159 	/*
160 	 * We also support the following 'traditional' syntax:
161 	 * iostat [drives] [wait [count]]
162 	 * This isn't mentioned in the man page, or the usage statement,
163 	 * but it is supported.
164 	 */
165 	fprintf(stderr, "usage: iostat [-CdhIKoTxz?] [-c count] [-M core]"
166 		" [-n devs] [-N system]\n"
167 		"\t      [-t type,if,pass] [-w wait] [drives]\n");
168 }
169 
170 int
171 main(int argc, char **argv)
172 {
173 	int c, i;
174 	int tflag = 0, hflag = 0, cflag = 0, wflag = 0, nflag = 0;
175 	int count = 0, waittime = 0;
176 	char *memf = NULL, *nlistf = NULL;
177 	struct devstat_match *matches;
178 	int num_matches = 0;
179 	char errbuf[_POSIX2_LINE_MAX];
180 	kvm_t *kd = NULL;
181 	long generation;
182 	int num_devices_specified;
183 	int num_selected, num_selections;
184 	long select_generation;
185 	char **specified_devices;
186 	devstat_select_mode select_mode;
187 	float f;
188 	int havelast = 0;
189 
190 	matches = NULL;
191 	maxshowdevs = 3;
192 
193 	while ((c = getopt(argc, argv, "c:CdhIKM:n:N:ot:Tw:xz?")) != -1) {
194 		switch(c) {
195 			case 'c':
196 				cflag++;
197 				count = atoi(optarg);
198 				if (count < 1)
199 					errx(1, "count %d is < 1", count);
200 				break;
201 			case 'C':
202 				Cflag++;
203 				break;
204 			case 'd':
205 				dflag++;
206 				break;
207 			case 'h':
208 				hflag++;
209 				break;
210 			case 'I':
211 				Iflag++;
212 				break;
213 			case 'K':
214 				Kflag++;
215 				break;
216 			case 'M':
217 				memf = optarg;
218 				break;
219 			case 'n':
220 				nflag++;
221 				maxshowdevs = atoi(optarg);
222 				if (maxshowdevs < 0)
223 					errx(1, "number of devices %d is < 0",
224 					     maxshowdevs);
225 				break;
226 			case 'N':
227 				nlistf = optarg;
228 				break;
229 			case 'o':
230 				oflag++;
231 				break;
232 			case 't':
233 				tflag++;
234 				if (devstat_buildmatch(optarg, &matches,
235 						       &num_matches) != 0)
236 					errx(1, "%s", devstat_errbuf);
237 				break;
238 			case 'T':
239 				Tflag++;
240 				break;
241 			case 'w':
242 				wflag++;
243 				f = atof(optarg);
244 				waittime = f * 1000;
245 				if (waittime < 1)
246 					errx(1, "wait time is < 1ms");
247 				break;
248 			case 'x':
249 				xflag++;
250 				break;
251 			case 'z':
252 				zflag++;
253 				break;
254 			default:
255 				usage();
256 				exit(1);
257 				break;
258 		}
259 	}
260 
261 	argc -= optind;
262 	argv += optind;
263 
264 	if (nlistf != NULL || memf != NULL) {
265 		kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
266 
267 		if (kd == NULL)
268 			errx(1, "kvm_openfiles: %s", errbuf);
269 
270 		if (kvm_nlist(kd, namelist) == -1)
271 			errx(1, "kvm_nlist: %s", kvm_geterr(kd));
272 	}
273 
274 	/*
275 	 * Make sure that the userland devstat version matches the kernel
276 	 * devstat version.  If not, exit and print a message informing
277 	 * the user of his mistake.
278 	 */
279 	if (devstat_checkversion(kd) < 0)
280 		errx(1, "%s", devstat_errbuf);
281 
282 	/*
283 	 * Make sure Tflag and/or Cflag are set if dflag == 0.  If dflag is
284 	 * greater than 0, they may be 0 or non-zero.
285 	 */
286 	if (dflag == 0 && xflag == 0) {
287 		Cflag = 1;
288 		Tflag = 1;
289 	}
290 
291 	/* find out how many devices we have */
292 	if ((num_devices = devstat_getnumdevs(kd)) < 0)
293 		err(1, "can't get number of devices");
294 
295 	/*
296 	 * Figure out how many devices we should display.
297 	 */
298 	if (nflag == 0) {
299 		if (xflag > 0)
300 			maxshowdevs = num_devices;
301 		else if (oflag > 0) {
302 			if ((dflag > 0) && (Cflag == 0) && (Tflag == 0))
303 				maxshowdevs = 5;
304 			else if ((dflag > 0) && (Tflag > 0) && (Cflag == 0))
305 				maxshowdevs = 5;
306 			else
307 				maxshowdevs = 4;
308 		} else {
309 			if ((dflag > 0) && (Cflag == 0))
310 				maxshowdevs = 4;
311 			else
312 				maxshowdevs = 3;
313 		}
314 	}
315 
316 	cur.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
317 	if (cur.dinfo == NULL)
318 		err(1, "calloc failed");
319 
320 	last.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
321 	if (last.dinfo == NULL)
322 		err(1, "calloc failed");
323 
324 	/*
325 	 * Grab all the devices.  We don't look to see if the list has
326 	 * changed here, since it almost certainly has.  We only look for
327 	 * errors.
328 	 */
329 	if (devstat_getdevs(kd, &cur) == -1)
330 		errx(1, "%s", devstat_errbuf);
331 
332 	num_devices = cur.dinfo->numdevs;
333 	generation = cur.dinfo->generation;
334 
335 	/*
336 	 * If the user specified any devices on the command line, see if
337 	 * they are in the list of devices we have now.
338 	 */
339 	specified_devices = (char **)malloc(sizeof(char *));
340 	if (specified_devices == NULL)
341 		err(1, "malloc failed");
342 
343 	for (num_devices_specified = 0; *argv; ++argv) {
344 		if (isdigit(**argv))
345 			break;
346 		num_devices_specified++;
347 		specified_devices = (char **)realloc(specified_devices,
348 						     sizeof(char *) *
349 						     num_devices_specified);
350 		if (specified_devices == NULL)
351 			err(1, "realloc failed");
352 
353 		specified_devices[num_devices_specified - 1] = *argv;
354 
355 	}
356 	if (nflag == 0 && maxshowdevs < num_devices_specified)
357 		maxshowdevs = num_devices_specified;
358 
359 	dev_select = NULL;
360 
361 	if ((num_devices_specified == 0) && (num_matches == 0))
362 		select_mode = DS_SELECT_ADD;
363 	else
364 		select_mode = DS_SELECT_ONLY;
365 
366 	/*
367 	 * At this point, selectdevs will almost surely indicate that the
368 	 * device list has changed, so we don't look for return values of 0
369 	 * or 1.  If we get back -1, though, there is an error.
370 	 */
371 	if (devstat_selectdevs(&dev_select, &num_selected,
372 			       &num_selections, &select_generation, generation,
373 			       cur.dinfo->devices, num_devices, matches,
374 			       num_matches, specified_devices,
375 			       num_devices_specified, select_mode, maxshowdevs,
376 			       hflag) == -1)
377 		errx(1, "%s", devstat_errbuf);
378 
379 	/*
380 	 * Look for the traditional wait time and count arguments.
381 	 */
382 	if (*argv) {
383 		f = atof(*argv);
384 		waittime = f * 1000;
385 
386 		/* Let the user know he goofed, but keep going anyway */
387 		if (wflag != 0)
388 			warnx("discarding previous wait interval, using"
389 			      " %g instead", waittime / 1000.0);
390 		wflag++;
391 
392 		if (*++argv) {
393 			count = atoi(*argv);
394 			if (cflag != 0)
395 				warnx("discarding previous count, using %d"
396 				      " instead", count);
397 			cflag++;
398 		} else
399 			count = -1;
400 	}
401 
402 	/*
403 	 * If the user specified a count, but not an interval, we default
404 	 * to an interval of 1 second.
405 	 */
406 	if ((wflag == 0) && (cflag > 0))
407 		waittime = 1 * 1000;
408 
409 	/*
410 	 * If the user specified a wait time, but not a count, we want to
411 	 * go on ad infinitum.  This can be redundant if the user uses the
412 	 * traditional method of specifying the wait, since in that case we
413 	 * already set count = -1 above.  Oh well.
414 	 */
415 	if ((wflag > 0) && (cflag == 0))
416 		count = -1;
417 
418 	bzero(cur.cp_time, sizeof(cur.cp_time));
419 	cur.tk_nout = 0;
420 	cur.tk_nin = 0;
421 
422 	/*
423 	 * Set the snap time to the system boot time (ie: zero), so the
424 	 * stats are calculated since system boot.
425 	 */
426 	cur.snap_time = 0;
427 
428 	/*
429 	 * If the user stops the program (control-Z) and then resumes it,
430 	 * print out the header again.
431 	 */
432 	(void)signal(SIGCONT, needhdr);
433 
434 	/*
435 	 * If our standard output is a tty, then install a SIGWINCH handler
436 	 * and set wresized so that our first iteration through the main
437 	 * iostat loop will peek at the terminal's current rows to find out
438 	 * how many lines can fit in a screenful of output.
439 	 */
440 	if (isatty(fileno(stdout)) != 0) {
441 		wresized = 1;
442 		(void)signal(SIGWINCH, needresize);
443 	} else {
444 		wresized = 0;
445 		wrows = IOSTAT_DEFAULT_ROWS;
446 	}
447 
448 	for (headercount = 1;;) {
449 		struct devinfo *tmp_dinfo;
450 		long tmp;
451 		long double etime;
452 
453 		if (Tflag > 0) {
454 			if ((readvar(kd, "kern.tty_nin", X_TK_NIN, &cur.tk_nin,
455 			     sizeof(cur.tk_nin)) != 0)
456 			 || (readvar(kd, "kern.tty_nout", X_TK_NOUT,
457 			     &cur.tk_nout, sizeof(cur.tk_nout))!= 0)) {
458 				Tflag = 0;
459 				warnx("disabling TTY statistics");
460 			}
461 		 }
462 
463 		if (Cflag > 0) {
464 			if (kd == NULL) {
465 				if (readvar(kd, "kern.cp_time", 0,
466 				    &cur.cp_time, sizeof(cur.cp_time)) != 0)
467 					Cflag = 0;
468 			} else {
469 				if (kvm_getcptime(kd, cur.cp_time) < 0) {
470 					warnx("kvm_getcptime: %s",
471 					    kvm_geterr(kd));
472 					Cflag = 0;
473 				}
474 			}
475 			if (Cflag == 0)
476 				warnx("disabling CPU time statistics");
477 		}
478 
479 		if (!--headercount) {
480 			phdr();
481 			if (wresized != 0)
482 				doresize();
483 			headercount = wrows;
484 		}
485 
486 		tmp_dinfo = last.dinfo;
487 		last.dinfo = cur.dinfo;
488 		cur.dinfo = tmp_dinfo;
489 
490 		last.snap_time = cur.snap_time;
491 
492 		/*
493 		 * Here what we want to do is refresh our device stats.
494 		 * devstat_getdevs() returns 1 when the device list has changed.
495 		 * If the device list has changed, we want to go through
496 		 * the selection process again, in case a device that we
497 		 * were previously displaying has gone away.
498 		 */
499 		switch (devstat_getdevs(kd, &cur)) {
500 		case -1:
501 			errx(1, "%s", devstat_errbuf);
502 			break;
503 		case 1: {
504 			int retval;
505 
506 			num_devices = cur.dinfo->numdevs;
507 			generation = cur.dinfo->generation;
508 			retval = devstat_selectdevs(&dev_select, &num_selected,
509 						    &num_selections,
510 						    &select_generation,
511 						    generation,
512 						    cur.dinfo->devices,
513 						    num_devices, matches,
514 						    num_matches,
515 						    specified_devices,
516 						    num_devices_specified,
517 						    select_mode, maxshowdevs,
518 						    hflag);
519 			switch(retval) {
520 			case -1:
521 				errx(1, "%s", devstat_errbuf);
522 				break;
523 			case 1:
524 				phdr();
525 				if (wresized != 0)
526 					doresize();
527 				headercount = wrows;
528 				break;
529 			default:
530 				break;
531 			}
532 			break;
533 		}
534 		default:
535 			break;
536 		}
537 
538 		/*
539 		 * We only want to re-select devices if we're in 'top'
540 		 * mode.  This is the only mode where the devices selected
541 		 * could actually change.
542 		 */
543 		if (hflag > 0) {
544 			int retval;
545 			retval = devstat_selectdevs(&dev_select, &num_selected,
546 						    &num_selections,
547 						    &select_generation,
548 						    generation,
549 						    cur.dinfo->devices,
550 						    num_devices, matches,
551 						    num_matches,
552 						    specified_devices,
553 						    num_devices_specified,
554 						    select_mode, maxshowdevs,
555 						    hflag);
556 			switch(retval) {
557 			case -1:
558 				errx(1,"%s", devstat_errbuf);
559 				break;
560 			case 1:
561 				phdr();
562 				if (wresized != 0)
563 					doresize();
564 				headercount = wrows;
565 				break;
566 			default:
567 				break;
568 			}
569 		}
570 
571 		if (Tflag > 0) {
572 			tmp = cur.tk_nin;
573 			cur.tk_nin -= last.tk_nin;
574 			last.tk_nin = tmp;
575 			tmp = cur.tk_nout;
576 			cur.tk_nout -= last.tk_nout;
577 			last.tk_nout = tmp;
578 		}
579 
580 		etime = cur.snap_time - last.snap_time;
581 
582 		if (etime == 0.0)
583 			etime = 1.0;
584 
585 		for (i = 0; i < CPUSTATES; i++) {
586 			tmp = cur.cp_time[i];
587 			cur.cp_time[i] -= last.cp_time[i];
588 			last.cp_time[i] = tmp;
589 		}
590 
591 		if (xflag == 0 && Tflag > 0)
592 			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
593 			    cur.tk_nout / etime);
594 
595 		devstats(hflag, etime, havelast);
596 
597 		if (xflag == 0) {
598 			if (Cflag > 0)
599 				cpustats();
600 
601 			printf("\n");
602 		}
603 		fflush(stdout);
604 
605 		if (count >= 0 && --count <= 0)
606 			break;
607 
608 		usleep(waittime * 1000);
609 		havelast = 1;
610 	}
611 
612 	exit(0);
613 }
614 
615 /*
616  * Force a header to be prepended to the next output.
617  */
618 void
619 needhdr(int signo)
620 {
621 
622 	headercount = 1;
623 }
624 
625 /*
626  * When the terminal is resized, force an update of the maximum number of rows
627  * printed between each header repetition.  Then force a new header to be
628  * prepended to the next output.
629  */
630 void
631 needresize(int signo)
632 {
633 
634 	wresized = 1;
635 	headercount = 1;
636 }
637 
638 /*
639  * Update the global `wrows' count of terminal rows.
640  */
641 void
642 doresize(void)
643 {
644 	int status;
645 	struct winsize w;
646 
647 	for (;;) {
648 		status = ioctl(fileno(stdout), TIOCGWINSZ, &w);
649 		if (status == -1 && errno == EINTR)
650 			continue;
651 		else if (status == -1)
652 			err(1, "ioctl");
653 		if (w.ws_row > 3)
654 			wrows = w.ws_row - 3;
655 		else
656 			wrows = IOSTAT_DEFAULT_ROWS;
657 		break;
658 	}
659 
660 	/*
661 	 * Inhibit doresize() calls until we are rescheduled by SIGWINCH.
662 	 */
663 	wresized = 0;
664 }
665 
666 static void
667 phdr(void)
668 {
669 	int i, printed;
670 	char devbuf[256];
671 
672 	/*
673 	 * If xflag is set, we need a per-loop header, not a page header, so
674 	 * just return.  We'll print the header in devstats().
675 	 */
676 	if (xflag > 0)
677 		return;
678 
679 	if (Tflag > 0)
680 		(void)printf("       tty");
681 	for (i = 0, printed=0;(i < num_devices) && (printed < maxshowdevs);i++){
682 		int di;
683 		if ((dev_select[i].selected != 0)
684 		 && (dev_select[i].selected <= maxshowdevs)) {
685 			di = dev_select[i].position;
686 			snprintf(devbuf, sizeof(devbuf), "%s%d",
687 					    cur.dinfo->devices[di].device_name,
688 					    cur.dinfo->devices[di].unit_number);
689 			if (oflag > 0)
690 				(void)printf("%13.6s ", devbuf);
691 			else
692 				printf("%16.6s ", devbuf);
693 			printed++;
694 		}
695 	}
696 	if (Cflag > 0)
697 		(void)printf("            cpu\n");
698 	else
699 		(void)printf("\n");
700 
701 	if (Tflag > 0)
702 		(void)printf(" tin  tout");
703 
704 	for (i=0, printed = 0;(i < num_devices) && (printed < maxshowdevs);i++){
705 		if ((dev_select[i].selected != 0)
706 		 && (dev_select[i].selected <= maxshowdevs)) {
707 			if (oflag > 0) {
708 				if (Iflag == 0)
709 					(void)printf(" sps tps msps ");
710 				else
711 					(void)printf(" blk xfr msps ");
712 			} else {
713 				if (Iflag == 0)
714 					printf("  KB/t tps  MB/s ");
715 				else
716 					printf("  KB/t xfrs   MB ");
717 			}
718 			printed++;
719 		}
720 	}
721 	if (Cflag > 0)
722 		(void)printf(" us ni sy in id\n");
723 	else
724 		printf("\n");
725 
726 }
727 
728 static void
729 devstats(int perf_select, long double etime, int havelast)
730 {
731 	int dn;
732 	long double transfers_per_second, transfers_per_second_read, transfers_per_second_write;
733 	long double kb_per_transfer, mb_per_second, mb_per_second_read, mb_per_second_write;
734 	u_int64_t total_bytes, total_transfers, total_blocks;
735 	u_int64_t total_bytes_read, total_transfers_read;
736 	u_int64_t total_bytes_write, total_transfers_write;
737 	long double busy_pct;
738 	u_int64_t queue_len;
739 	long double total_mb;
740 	long double blocks_per_second, ms_per_transaction;
741 	int firstline = 1;
742 	char *devname;
743 
744 	if (xflag > 0) {
745 		printf("                        extended device statistics  ");
746 		if (Tflag > 0)
747 			printf("      tty ");
748 		if (Cflag > 0)
749 			printf("           cpu ");
750 		printf("\n");
751 		if (Iflag == 0)
752 			printf(
753 		"device     r/s   w/s    kr/s    kw/s wait svc_t  %%b  "
754 			    );
755 		else
756 			printf(
757 		"device     r/i   w/i    kr/i    kw/i wait svc_t  %%b  "
758 			    );
759 		if (Tflag > 0)
760 			printf("tin  tout ");
761 		if (Cflag > 0)
762 			printf("us ni sy in id ");
763 		printf("\n");
764 	}
765 
766 	for (dn = 0; dn < num_devices; dn++) {
767 		int di;
768 
769 		if (((perf_select == 0) && (dev_select[dn].selected == 0))
770 		 || (dev_select[dn].selected > maxshowdevs))
771 			continue;
772 
773 		di = dev_select[dn].position;
774 
775 		if (devstat_compute_statistics(&cur.dinfo->devices[di],
776 		    havelast ? &last.dinfo->devices[di] : NULL, etime,
777 		    DSM_TOTAL_BYTES, &total_bytes,
778 		    DSM_TOTAL_BYTES_READ, &total_bytes_read,
779 		    DSM_TOTAL_BYTES_WRITE, &total_bytes_write,
780 		    DSM_TOTAL_TRANSFERS, &total_transfers,
781 		    DSM_TOTAL_TRANSFERS_READ, &total_transfers_read,
782 		    DSM_TOTAL_TRANSFERS_WRITE, &total_transfers_write,
783 		    DSM_TOTAL_BLOCKS, &total_blocks,
784 		    DSM_KB_PER_TRANSFER, &kb_per_transfer,
785 		    DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
786 		    DSM_TRANSFERS_PER_SECOND_READ, &transfers_per_second_read,
787 		    DSM_TRANSFERS_PER_SECOND_WRITE, &transfers_per_second_write,
788 		    DSM_MB_PER_SECOND, &mb_per_second,
789 		    DSM_MB_PER_SECOND_READ, &mb_per_second_read,
790 		    DSM_MB_PER_SECOND_WRITE, &mb_per_second_write,
791 		    DSM_BLOCKS_PER_SECOND, &blocks_per_second,
792 		    DSM_MS_PER_TRANSACTION, &ms_per_transaction,
793 		    DSM_BUSY_PCT, &busy_pct,
794 		    DSM_QUEUE_LENGTH, &queue_len,
795 		    DSM_NONE) != 0)
796 			errx(1, "%s", devstat_errbuf);
797 
798 		if (perf_select != 0) {
799 			dev_select[dn].bytes = total_bytes;
800 			if ((dev_select[dn].selected == 0)
801 			 || (dev_select[dn].selected > maxshowdevs))
802 				continue;
803 		}
804 
805 		if (Kflag > 0 || xflag > 0) {
806 			int block_size = cur.dinfo->devices[di].block_size;
807 			total_blocks = total_blocks * (block_size ?
808 						       block_size : 512) / 1024;
809 		}
810 
811 		if (xflag > 0) {
812 			if (asprintf(&devname, "%s%d",
813 			    cur.dinfo->devices[di].device_name,
814 			    cur.dinfo->devices[di].unit_number) == -1)
815 				err(1, "asprintf");
816 			/*
817 			 * If zflag is set, skip any devices with zero I/O.
818 			 */
819 			if (zflag == 0 || transfers_per_second_read > 0.05 ||
820 			    transfers_per_second_write > 0.05 ||
821 			    mb_per_second_read > ((long double).0005)/1024 ||
822 			    mb_per_second_write > ((long double).0005)/1024 ||
823 			    busy_pct > 0.5) {
824 				if (Iflag == 0)
825 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
826 					    devname, transfers_per_second_read,
827 					    transfers_per_second_write,
828 					    mb_per_second_read * 1024,
829 					    mb_per_second_write * 1024,
830 					    queue_len,
831 					    ms_per_transaction, busy_pct);
832 				else
833 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
834 					    devname,
835 					    (long double)total_transfers_read,
836 					    (long double)total_transfers_write,
837 					    (long double)
838 					        total_bytes_read / 1024,
839 					    (long double)
840 					        total_bytes_write / 1024,
841 					    queue_len,
842 					    ms_per_transaction, busy_pct);
843 				if (firstline) {
844 					/*
845 					 * If this is the first device
846 					 * we're printing, also print
847 					 * CPU or TTY stats if requested.
848 					 */
849 					firstline = 0;
850 					if (Tflag > 0)
851 						printf("%4.0Lf%5.0Lf",
852 						    cur.tk_nin / etime,
853 						    cur.tk_nout / etime);
854 					if (Cflag > 0)
855 						cpustats();
856 				}
857 				printf("\n");
858 			}
859 			free(devname);
860 		} else if (oflag > 0) {
861 			int msdig = (ms_per_transaction < 100.0) ? 1 : 0;
862 
863 			if (Iflag == 0)
864 				printf("%4.0Lf%4.0Lf%5.*Lf ",
865 				       blocks_per_second,
866 				       transfers_per_second,
867 				       msdig,
868 				       ms_per_transaction);
869 			else
870 				printf("%4.1qu%4.1qu%5.*Lf ",
871 				       total_blocks,
872 				       total_transfers,
873 				       msdig,
874 				       ms_per_transaction);
875 		} else {
876 			if (Iflag == 0)
877 				printf(" %5.2Lf %3.0Lf %5.2Lf ",
878 				       kb_per_transfer,
879 				       transfers_per_second,
880 				       mb_per_second);
881 			else {
882 				total_mb = total_bytes;
883 				total_mb /= 1024 * 1024;
884 
885 				printf(" %5.2Lf %3.1qu %5.2Lf ",
886 				       kb_per_transfer,
887 				       total_transfers,
888 				       total_mb);
889 			}
890 		}
891 	}
892 	if (xflag > 0 && zflag > 0 && firstline == 1 &&
893 	    (Tflag > 0 || Cflag > 0)) {
894 		/*
895 		 * If zflag is set and we did not print any device
896 		 * lines I/O because they were all zero,
897 		 * print TTY/CPU stats.
898 		 */
899 		printf("%52s","");
900 		if (Tflag > 0)
901 			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
902 			    cur.tk_nout / etime);
903 		if (Cflag > 0)
904 			cpustats();
905 		printf("\n");
906 	}
907 }
908 
909 static void
910 cpustats(void)
911 {
912 	int state;
913 	double time;
914 
915 	time = 0.0;
916 
917 	for (state = 0; state < CPUSTATES; ++state)
918 		time += cur.cp_time[state];
919 	for (state = 0; state < CPUSTATES; ++state)
920 		printf(" %2.0f",
921 		       rint(100. * cur.cp_time[state] / (time ? time : 1)));
922 }
923 
924 static int
925 readvar(kvm_t *kd, const char *name, int nlid, void *ptr, size_t len)
926 {
927 	if (kd != NULL) {
928 		ssize_t nbytes;
929 
930 		nbytes = kvm_read(kd, namelist[nlid].n_value, ptr, len);
931 
932 		if (nbytes < 0) {
933 			warnx("kvm_read(%s): %s", namelist[nlid].n_name,
934 			    kvm_geterr(kd));
935 			return (1);
936 		}
937 		if (nbytes != len) {
938 			warnx("kvm_read(%s): expected %zu bytes, got %zd bytes",
939 			      namelist[nlid].n_name, len, nbytes);
940 			return (1);
941 		}
942 	} else {
943 		size_t nlen = len;
944 
945 		if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
946 			warn("sysctl(%s...) failed", name);
947 			return (1);
948 		}
949 		if (nlen != len) {
950 			warnx("sysctl(%s...): expected %lu, got %lu", name,
951 			      (unsigned long)len, (unsigned long)nlen);
952 			return (1);
953 		}
954 	}
955 	return (0);
956 }
957