xref: /freebsd/usr.sbin/iostat/iostat.c (revision cf4c5a533126ca1ddb1f070af73f8f53b9e77fd4)
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 	int havelast = 0;
188 
189 	matches = NULL;
190 	maxshowdevs = 3;
191 
192 	while ((c = getopt(argc, argv, "c:CdhIKM:n:N:ot:Tw:xz?")) != -1) {
193 		switch(c) {
194 			case 'c':
195 				cflag++;
196 				count = atoi(optarg);
197 				if (count < 1)
198 					errx(1, "count %d is < 1", count);
199 				break;
200 			case 'C':
201 				Cflag++;
202 				break;
203 			case 'd':
204 				dflag++;
205 				break;
206 			case 'h':
207 				hflag++;
208 				break;
209 			case 'I':
210 				Iflag++;
211 				break;
212 			case 'K':
213 				Kflag++;
214 				break;
215 			case 'M':
216 				memf = optarg;
217 				break;
218 			case 'n':
219 				nflag++;
220 				maxshowdevs = atoi(optarg);
221 				if (maxshowdevs < 0)
222 					errx(1, "number of devices %d is < 0",
223 					     maxshowdevs);
224 				break;
225 			case 'N':
226 				nlistf = optarg;
227 				break;
228 			case 'o':
229 				oflag++;
230 				break;
231 			case 't':
232 				tflag++;
233 				if (devstat_buildmatch(optarg, &matches,
234 						       &num_matches) != 0)
235 					errx(1, "%s", devstat_errbuf);
236 				break;
237 			case 'T':
238 				Tflag++;
239 				break;
240 			case 'w':
241 				wflag++;
242 				waittime = atoi(optarg);
243 				if (waittime < 1)
244 					errx(1, "wait time is < 1");
245 				break;
246 			case 'x':
247 				xflag++;
248 				break;
249 			case 'z':
250 				zflag++;
251 				break;
252 			default:
253 				usage();
254 				exit(1);
255 				break;
256 		}
257 	}
258 
259 	argc -= optind;
260 	argv += optind;
261 
262 	if (nlistf != NULL || memf != NULL) {
263 		kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
264 
265 		if (kd == NULL)
266 			errx(1, "kvm_openfiles: %s", errbuf);
267 
268 		if (kvm_nlist(kd, namelist) == -1)
269 			errx(1, "kvm_nlist: %s", kvm_geterr(kd));
270 	}
271 
272 	/*
273 	 * Make sure that the userland devstat version matches the kernel
274 	 * devstat version.  If not, exit and print a message informing
275 	 * the user of his mistake.
276 	 */
277 	if (devstat_checkversion(kd) < 0)
278 		errx(1, "%s", devstat_errbuf);
279 
280 	/*
281 	 * Make sure Tflag and/or Cflag are set if dflag == 0.  If dflag is
282 	 * greater than 0, they may be 0 or non-zero.
283 	 */
284 	if (dflag == 0 && xflag == 0) {
285 		Cflag = 1;
286 		Tflag = 1;
287 	}
288 
289 	/* find out how many devices we have */
290 	if ((num_devices = devstat_getnumdevs(kd)) < 0)
291 		err(1, "can't get number of devices");
292 
293 	/*
294 	 * Figure out how many devices we should display.
295 	 */
296 	if (nflag == 0) {
297 		if (xflag > 0)
298 			maxshowdevs = num_devices;
299 		else if (oflag > 0) {
300 			if ((dflag > 0) && (Cflag == 0) && (Tflag == 0))
301 				maxshowdevs = 5;
302 			else if ((dflag > 0) && (Tflag > 0) && (Cflag == 0))
303 				maxshowdevs = 5;
304 			else
305 				maxshowdevs = 4;
306 		} else {
307 			if ((dflag > 0) && (Cflag == 0))
308 				maxshowdevs = 4;
309 			else
310 				maxshowdevs = 3;
311 		}
312 	}
313 
314 	cur.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
315 	if (cur.dinfo == NULL)
316 		err(1, "calloc failed");
317 
318 	last.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
319 	if (last.dinfo == NULL)
320 		err(1, "calloc failed");
321 
322 	/*
323 	 * Grab all the devices.  We don't look to see if the list has
324 	 * changed here, since it almost certainly has.  We only look for
325 	 * errors.
326 	 */
327 	if (devstat_getdevs(kd, &cur) == -1)
328 		errx(1, "%s", devstat_errbuf);
329 
330 	num_devices = cur.dinfo->numdevs;
331 	generation = cur.dinfo->generation;
332 
333 	/*
334 	 * If the user specified any devices on the command line, see if
335 	 * they are in the list of devices we have now.
336 	 */
337 	specified_devices = (char **)malloc(sizeof(char *));
338 	if (specified_devices == NULL)
339 		err(1, "malloc failed");
340 
341 	for (num_devices_specified = 0; *argv; ++argv) {
342 		if (isdigit(**argv))
343 			break;
344 		num_devices_specified++;
345 		specified_devices = (char **)realloc(specified_devices,
346 						     sizeof(char *) *
347 						     num_devices_specified);
348 		if (specified_devices == NULL)
349 			err(1, "realloc failed");
350 
351 		specified_devices[num_devices_specified - 1] = *argv;
352 
353 	}
354 	if (nflag == 0 && maxshowdevs < num_devices_specified)
355 		maxshowdevs = num_devices_specified;
356 
357 	dev_select = NULL;
358 
359 	if ((num_devices_specified == 0) && (num_matches == 0))
360 		select_mode = DS_SELECT_ADD;
361 	else
362 		select_mode = DS_SELECT_ONLY;
363 
364 	/*
365 	 * At this point, selectdevs will almost surely indicate that the
366 	 * device list has changed, so we don't look for return values of 0
367 	 * or 1.  If we get back -1, though, there is an error.
368 	 */
369 	if (devstat_selectdevs(&dev_select, &num_selected,
370 			       &num_selections, &select_generation, generation,
371 			       cur.dinfo->devices, num_devices, matches,
372 			       num_matches, specified_devices,
373 			       num_devices_specified, select_mode, maxshowdevs,
374 			       hflag) == -1)
375 		errx(1, "%s", devstat_errbuf);
376 
377 	/*
378 	 * Look for the traditional wait time and count arguments.
379 	 */
380 	if (*argv) {
381 		waittime = atoi(*argv);
382 
383 		/* Let the user know he goofed, but keep going anyway */
384 		if (wflag != 0)
385 			warnx("discarding previous wait interval, using"
386 			      " %d instead", waittime);
387 		wflag++;
388 
389 		if (*++argv) {
390 			count = atoi(*argv);
391 			if (cflag != 0)
392 				warnx("discarding previous count, using %d"
393 				      " instead", count);
394 			cflag++;
395 		} else
396 			count = -1;
397 	}
398 
399 	/*
400 	 * If the user specified a count, but not an interval, we default
401 	 * to an interval of 1 second.
402 	 */
403 	if ((wflag == 0) && (cflag > 0))
404 		waittime = 1;
405 
406 	/*
407 	 * If the user specified a wait time, but not a count, we want to
408 	 * go on ad infinitum.  This can be redundant if the user uses the
409 	 * traditional method of specifying the wait, since in that case we
410 	 * already set count = -1 above.  Oh well.
411 	 */
412 	if ((wflag > 0) && (cflag == 0))
413 		count = -1;
414 
415 	bzero(cur.cp_time, sizeof(cur.cp_time));
416 	cur.tk_nout = 0;
417 	cur.tk_nin = 0;
418 
419 	/*
420 	 * Set the snap time to the system boot time (ie: zero), so the
421 	 * stats are calculated since system boot.
422 	 */
423 	cur.snap_time = 0;
424 
425 	/*
426 	 * If the user stops the program (control-Z) and then resumes it,
427 	 * print out the header again.
428 	 */
429 	(void)signal(SIGCONT, needhdr);
430 
431 	/*
432 	 * If our standard output is a tty, then install a SIGWINCH handler
433 	 * and set wresized so that our first iteration through the main
434 	 * iostat loop will peek at the terminal's current rows to find out
435 	 * how many lines can fit in a screenful of output.
436 	 */
437 	if (isatty(fileno(stdout)) != 0) {
438 		wresized = 1;
439 		(void)signal(SIGWINCH, needresize);
440 	} else {
441 		wresized = 0;
442 		wrows = IOSTAT_DEFAULT_ROWS;
443 	}
444 
445 	for (headercount = 1;;) {
446 		struct devinfo *tmp_dinfo;
447 		long tmp;
448 		long double etime;
449 
450 		if (Tflag > 0) {
451 			if ((readvar(kd, "kern.tty_nin", X_TK_NIN, &cur.tk_nin,
452 			     sizeof(cur.tk_nin)) != 0)
453 			 || (readvar(kd, "kern.tty_nout", X_TK_NOUT,
454 			     &cur.tk_nout, sizeof(cur.tk_nout))!= 0)) {
455 				Tflag = 0;
456 				warnx("disabling TTY statistics");
457 			}
458 		 }
459 
460 		if (Cflag > 0) {
461 			if (kd == NULL) {
462 				if (readvar(kd, "kern.cp_time", 0,
463 				    &cur.cp_time, sizeof(cur.cp_time)) != 0)
464 					Cflag = 0;
465 			} else {
466 				if (kvm_getcptime(kd, cur.cp_time) < 0) {
467 					warnx("kvm_getcptime: %s",
468 					    kvm_geterr(kd));
469 					Cflag = 0;
470 				}
471 			}
472 			if (Cflag == 0)
473 				warnx("disabling CPU time statistics");
474 		}
475 
476 		if (!--headercount) {
477 			phdr();
478 			if (wresized != 0)
479 				doresize();
480 			headercount = wrows;
481 		}
482 
483 		tmp_dinfo = last.dinfo;
484 		last.dinfo = cur.dinfo;
485 		cur.dinfo = tmp_dinfo;
486 
487 		last.snap_time = cur.snap_time;
488 
489 		/*
490 		 * Here what we want to do is refresh our device stats.
491 		 * devstat_getdevs() returns 1 when the device list has changed.
492 		 * If the device list has changed, we want to go through
493 		 * the selection process again, in case a device that we
494 		 * were previously displaying has gone away.
495 		 */
496 		switch (devstat_getdevs(kd, &cur)) {
497 		case -1:
498 			errx(1, "%s", devstat_errbuf);
499 			break;
500 		case 1: {
501 			int retval;
502 
503 			num_devices = cur.dinfo->numdevs;
504 			generation = cur.dinfo->generation;
505 			retval = devstat_selectdevs(&dev_select, &num_selected,
506 						    &num_selections,
507 						    &select_generation,
508 						    generation,
509 						    cur.dinfo->devices,
510 						    num_devices, matches,
511 						    num_matches,
512 						    specified_devices,
513 						    num_devices_specified,
514 						    select_mode, maxshowdevs,
515 						    hflag);
516 			switch(retval) {
517 			case -1:
518 				errx(1, "%s", devstat_errbuf);
519 				break;
520 			case 1:
521 				phdr();
522 				if (wresized != 0)
523 					doresize();
524 				headercount = wrows;
525 				break;
526 			default:
527 				break;
528 			}
529 			break;
530 		}
531 		default:
532 			break;
533 		}
534 
535 		/*
536 		 * We only want to re-select devices if we're in 'top'
537 		 * mode.  This is the only mode where the devices selected
538 		 * could actually change.
539 		 */
540 		if (hflag > 0) {
541 			int retval;
542 			retval = devstat_selectdevs(&dev_select, &num_selected,
543 						    &num_selections,
544 						    &select_generation,
545 						    generation,
546 						    cur.dinfo->devices,
547 						    num_devices, matches,
548 						    num_matches,
549 						    specified_devices,
550 						    num_devices_specified,
551 						    select_mode, maxshowdevs,
552 						    hflag);
553 			switch(retval) {
554 			case -1:
555 				errx(1,"%s", devstat_errbuf);
556 				break;
557 			case 1:
558 				phdr();
559 				if (wresized != 0)
560 					doresize();
561 				headercount = wrows;
562 				break;
563 			default:
564 				break;
565 			}
566 		}
567 
568 		if (Tflag > 0) {
569 			tmp = cur.tk_nin;
570 			cur.tk_nin -= last.tk_nin;
571 			last.tk_nin = tmp;
572 			tmp = cur.tk_nout;
573 			cur.tk_nout -= last.tk_nout;
574 			last.tk_nout = tmp;
575 		}
576 
577 		etime = cur.snap_time - last.snap_time;
578 
579 		if (etime == 0.0)
580 			etime = 1.0;
581 
582 		for (i = 0; i < CPUSTATES; i++) {
583 			tmp = cur.cp_time[i];
584 			cur.cp_time[i] -= last.cp_time[i];
585 			last.cp_time[i] = tmp;
586 		}
587 
588 		if (xflag == 0 && Tflag > 0)
589 			printf("%4.0Lf%5.0Lf", cur.tk_nin / etime,
590 			    cur.tk_nout / etime);
591 
592 		devstats(hflag, etime, havelast);
593 
594 		if (xflag == 0) {
595 			if (Cflag > 0)
596 				cpustats();
597 
598 			printf("\n");
599 		}
600 		fflush(stdout);
601 
602 		if (count >= 0 && --count <= 0)
603 			break;
604 
605 		sleep(waittime);
606 		havelast = 1;
607 	}
608 
609 	exit(0);
610 }
611 
612 /*
613  * Force a header to be prepended to the next output.
614  */
615 void
616 needhdr(int signo)
617 {
618 
619 	headercount = 1;
620 }
621 
622 /*
623  * When the terminal is resized, force an update of the maximum number of rows
624  * printed between each header repetition.  Then force a new header to be
625  * prepended to the next output.
626  */
627 void
628 needresize(int signo)
629 {
630 
631 	wresized = 1;
632 	headercount = 1;
633 }
634 
635 /*
636  * Update the global `wrows' count of terminal rows.
637  */
638 void
639 doresize(void)
640 {
641 	int status;
642 	struct winsize w;
643 
644 	for (;;) {
645 		status = ioctl(fileno(stdout), TIOCGWINSZ, &w);
646 		if (status == -1 && errno == EINTR)
647 			continue;
648 		else if (status == -1)
649 			err(1, "ioctl");
650 		if (w.ws_row > 3)
651 			wrows = w.ws_row - 3;
652 		else
653 			wrows = IOSTAT_DEFAULT_ROWS;
654 		break;
655 	}
656 
657 	/*
658 	 * Inhibit doresize() calls until we are rescheduled by SIGWINCH.
659 	 */
660 	wresized = 0;
661 }
662 
663 static void
664 phdr(void)
665 {
666 	int i, printed;
667 	char devbuf[256];
668 
669 	/*
670 	 * If xflag is set, we need a per-loop header, not a page header, so
671 	 * just return.  We'll print the header in devstats().
672 	 */
673 	if (xflag > 0)
674 		return;
675 
676 	if (Tflag > 0)
677 		(void)printf("      tty");
678 	for (i = 0, printed=0;(i < num_devices) && (printed < maxshowdevs);i++){
679 		int di;
680 		if ((dev_select[i].selected != 0)
681 		 && (dev_select[i].selected <= maxshowdevs)) {
682 			di = dev_select[i].position;
683 			snprintf(devbuf, sizeof(devbuf), "%s%d",
684 					    cur.dinfo->devices[di].device_name,
685 					    cur.dinfo->devices[di].unit_number);
686 			if (oflag > 0)
687 				(void)printf("%13.6s ", devbuf);
688 			else
689 				printf("%16.6s ", devbuf);
690 			printed++;
691 		}
692 	}
693 	if (Cflag > 0)
694 		(void)printf("            cpu\n");
695 	else
696 		(void)printf("\n");
697 
698 	if (Tflag > 0)
699 		(void)printf(" tin tout");
700 
701 	for (i=0, printed = 0;(i < num_devices) && (printed < maxshowdevs);i++){
702 		if ((dev_select[i].selected != 0)
703 		 && (dev_select[i].selected <= maxshowdevs)) {
704 			if (oflag > 0) {
705 				if (Iflag == 0)
706 					(void)printf(" sps tps msps ");
707 				else
708 					(void)printf(" blk xfr msps ");
709 			} else {
710 				if (Iflag == 0)
711 					printf("  KB/t tps  MB/s ");
712 				else
713 					printf("  KB/t xfrs   MB ");
714 			}
715 			printed++;
716 		}
717 	}
718 	if (Cflag > 0)
719 		(void)printf(" us ni sy in id\n");
720 	else
721 		printf("\n");
722 
723 }
724 
725 static void
726 devstats(int perf_select, long double etime, int havelast)
727 {
728 	int dn;
729 	long double transfers_per_second, transfers_per_second_read, transfers_per_second_write;
730 	long double kb_per_transfer, mb_per_second, mb_per_second_read, mb_per_second_write;
731 	u_int64_t total_bytes, total_transfers, total_blocks;
732 	u_int64_t total_bytes_read, total_transfers_read;
733 	u_int64_t total_bytes_write, total_transfers_write;
734 	long double busy_pct;
735 	u_int64_t queue_len;
736 	long double total_mb;
737 	long double blocks_per_second, ms_per_transaction;
738 	int firstline = 1;
739 	char *devname;
740 
741 	if (xflag > 0) {
742 		printf("                        extended device statistics  ");
743 		if (Tflag > 0)
744 			printf("     tty ");
745 		if (Cflag > 0)
746 			printf("           cpu ");
747 		printf("\n");
748 		if (Iflag == 0)
749 			printf(
750 		"device     r/s   w/s    kr/s    kw/s wait svc_t  %%b  "
751 			    );
752 		else
753 			printf(
754 		"device     r/i   w/i    kr/i    kw/i wait svc_t  %%b  "
755 			    );
756 		if (Tflag > 0)
757 			printf("tin tout ");
758 		if (Cflag > 0)
759 			printf("us ni sy in id ");
760 		printf("\n");
761 	}
762 
763 	for (dn = 0; dn < num_devices; dn++) {
764 		int di;
765 
766 		if (((perf_select == 0) && (dev_select[dn].selected == 0))
767 		 || (dev_select[dn].selected > maxshowdevs))
768 			continue;
769 
770 		di = dev_select[dn].position;
771 
772 		if (devstat_compute_statistics(&cur.dinfo->devices[di],
773 		    havelast ? &last.dinfo->devices[di] : NULL, etime,
774 		    DSM_TOTAL_BYTES, &total_bytes,
775 		    DSM_TOTAL_BYTES_READ, &total_bytes_read,
776 		    DSM_TOTAL_BYTES_WRITE, &total_bytes_write,
777 		    DSM_TOTAL_TRANSFERS, &total_transfers,
778 		    DSM_TOTAL_TRANSFERS_READ, &total_transfers_read,
779 		    DSM_TOTAL_TRANSFERS_WRITE, &total_transfers_write,
780 		    DSM_TOTAL_BLOCKS, &total_blocks,
781 		    DSM_KB_PER_TRANSFER, &kb_per_transfer,
782 		    DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
783 		    DSM_TRANSFERS_PER_SECOND_READ, &transfers_per_second_read,
784 		    DSM_TRANSFERS_PER_SECOND_WRITE, &transfers_per_second_write,
785 		    DSM_MB_PER_SECOND, &mb_per_second,
786 		    DSM_MB_PER_SECOND_READ, &mb_per_second_read,
787 		    DSM_MB_PER_SECOND_WRITE, &mb_per_second_write,
788 		    DSM_BLOCKS_PER_SECOND, &blocks_per_second,
789 		    DSM_MS_PER_TRANSACTION, &ms_per_transaction,
790 		    DSM_BUSY_PCT, &busy_pct,
791 		    DSM_QUEUE_LENGTH, &queue_len,
792 		    DSM_NONE) != 0)
793 			errx(1, "%s", devstat_errbuf);
794 
795 		if (perf_select != 0) {
796 			dev_select[dn].bytes = total_bytes;
797 			if ((dev_select[dn].selected == 0)
798 			 || (dev_select[dn].selected > maxshowdevs))
799 				continue;
800 		}
801 
802 		if (Kflag > 0 || xflag > 0) {
803 			int block_size = cur.dinfo->devices[di].block_size;
804 			total_blocks = total_blocks * (block_size ?
805 						       block_size : 512) / 1024;
806 		}
807 
808 		if (xflag > 0) {
809 			if (asprintf(&devname, "%s%d",
810 			    cur.dinfo->devices[di].device_name,
811 			    cur.dinfo->devices[di].unit_number) == -1)
812 				err(1, "asprintf");
813 			/*
814 			 * If zflag is set, skip any devices with zero I/O.
815 			 */
816 			if (zflag == 0 || transfers_per_second_read > 0.05 ||
817 			    transfers_per_second_write > 0.05 ||
818 			    mb_per_second_read > ((long double).0005)/1024 ||
819 			    mb_per_second_write > ((long double).0005)/1024 ||
820 			    busy_pct > 0.5) {
821 				if (Iflag == 0)
822 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
823 					    devname, transfers_per_second_read,
824 					    transfers_per_second_write,
825 					    mb_per_second_read * 1024,
826 					    mb_per_second_write * 1024,
827 					    queue_len,
828 					    ms_per_transaction, busy_pct);
829 				else
830 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
831 					    devname,
832 					    (long double)total_transfers_read,
833 					    (long double)total_transfers_write,
834 					    (long double)
835 					        total_bytes_read / 1024,
836 					    (long double)
837 					        total_bytes_write / 1024,
838 					    queue_len,
839 					    ms_per_transaction, busy_pct);
840 				if (firstline) {
841 					/*
842 					 * If this is the first device
843 					 * we're printing, also print
844 					 * CPU or TTY stats if requested.
845 					 */
846 					firstline = 0;
847 					if (Tflag > 0)
848 						printf("%4.0Lf%5.0Lf",
849 						    cur.tk_nin / etime,
850 						    cur.tk_nout / etime);
851 					if (Cflag > 0)
852 						cpustats();
853 				}
854 				printf("\n");
855 			}
856 			free(devname);
857 		} else if (oflag > 0) {
858 			int msdig = (ms_per_transaction < 100.0) ? 1 : 0;
859 
860 			if (Iflag == 0)
861 				printf("%4.0Lf%4.0Lf%5.*Lf ",
862 				       blocks_per_second,
863 				       transfers_per_second,
864 				       msdig,
865 				       ms_per_transaction);
866 			else
867 				printf("%4.1qu%4.1qu%5.*Lf ",
868 				       total_blocks,
869 				       total_transfers,
870 				       msdig,
871 				       ms_per_transaction);
872 		} else {
873 			if (Iflag == 0)
874 				printf(" %5.2Lf %3.0Lf %5.2Lf ",
875 				       kb_per_transfer,
876 				       transfers_per_second,
877 				       mb_per_second);
878 			else {
879 				total_mb = total_bytes;
880 				total_mb /= 1024 * 1024;
881 
882 				printf(" %5.2Lf %3.1qu %5.2Lf ",
883 				       kb_per_transfer,
884 				       total_transfers,
885 				       total_mb);
886 			}
887 		}
888 	}
889 	if (xflag > 0 && zflag > 0 && firstline == 1 &&
890 	    (Tflag > 0 || Cflag > 0)) {
891 		/*
892 		 * If zflag is set and we did not print any device
893 		 * lines I/O because they were all zero,
894 		 * print TTY/CPU stats.
895 		 */
896 		printf("%52s","");
897 		if (Tflag > 0)
898 			printf("%4.0Lf%5.0Lf", cur.tk_nin / etime,
899 			    cur.tk_nout / etime);
900 		if (Cflag > 0)
901 			cpustats();
902 		printf("\n");
903 	}
904 }
905 
906 static void
907 cpustats(void)
908 {
909 	int state;
910 	double time;
911 
912 	time = 0.0;
913 
914 	for (state = 0; state < CPUSTATES; ++state)
915 		time += cur.cp_time[state];
916 	for (state = 0; state < CPUSTATES; ++state)
917 		printf(" %2.0f",
918 		       rint(100. * cur.cp_time[state] / (time ? time : 1)));
919 }
920 
921 static int
922 readvar(kvm_t *kd, const char *name, int nlid, void *ptr, size_t len)
923 {
924 	if (kd != NULL) {
925 		ssize_t nbytes;
926 
927 		nbytes = kvm_read(kd, namelist[nlid].n_value, ptr, len);
928 
929 		if (nbytes < 0) {
930 			warnx("kvm_read(%s): %s", namelist[nlid].n_name,
931 			    kvm_geterr(kd));
932 			return (1);
933 		}
934 		if (nbytes != len) {
935 			warnx("kvm_read(%s): expected %zu bytes, got %zd bytes",
936 			      namelist[nlid].n_name, len, nbytes);
937 			return (1);
938 		}
939 	} else {
940 		size_t nlen = len;
941 
942 		if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
943 			warn("sysctl(%s...) failed", name);
944 			return (1);
945 		}
946 		if (nlen != len) {
947 			warnx("sysctl(%s...): expected %lu, got %lu", name,
948 			      (unsigned long)len, (unsigned long)nlen);
949 			return (1);
950 		}
951 	}
952 	return (0);
953 }
954