xref: /freebsd/usr.sbin/iostat/iostat.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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  * 4. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  */
62 /*
63  * Ideas for the new iostat statistics output modes taken from the NetBSD
64  * version of iostat:
65  */
66 /*
67  * Copyright (c) 1996 John M. Vinopal
68  * All rights reserved.
69  *
70  * Redistribution and use in source and binary forms, with or without
71  * modification, are permitted provided that the following conditions
72  * are met:
73  * 1. Redistributions of source code must retain the above copyright
74  *    notice, this list of conditions and the following disclaimer.
75  * 2. Redistributions in binary form must reproduce the above copyright
76  *    notice, this list of conditions and the following disclaimer in the
77  *    documentation and/or other materials provided with the distribution.
78  * 3. All advertising materials mentioning features or use of this software
79  *    must display the following acknowledgement:
80  *      This product includes software developed for the NetBSD Project
81  *      by John M. Vinopal.
82  * 4. The name of the author may not be used to endorse or promote products
83  *    derived from this software without specific prior written permission.
84  *
85  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
86  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
87  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
88  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
89  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
90  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
91  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
92  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
93  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
94  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
95  * SUCH DAMAGE.
96  */
97 
98 
99 #include <sys/param.h>
100 #include <sys/errno.h>
101 #include <sys/resource.h>
102 #include <sys/sysctl.h>
103 
104 #include <err.h>
105 #include <ctype.h>
106 #include <fcntl.h>
107 #include <kvm.h>
108 #include <nlist.h>
109 #include <stdio.h>
110 #include <stdlib.h>
111 #include <string.h>
112 #include <termios.h>
113 #include <unistd.h>
114 #include <limits.h>
115 #include <devstat.h>
116 #include <math.h>
117 
118 struct nlist namelist[] = {
119 #define X_TK_NIN	0
120 	{ "_tk_nin" },
121 #define X_TK_NOUT	1
122 	{ "_tk_nout" },
123 #define X_BOOTTIME	2
124 	{ "_boottime" },
125 #define X_END		2
126 	{ NULL },
127 };
128 
129 #define	IOSTAT_DEFAULT_ROWS	20	/* Traditional default `wrows' */
130 
131 struct statinfo cur, last;
132 int num_devices;
133 struct device_selection *dev_select;
134 int maxshowdevs;
135 volatile sig_atomic_t headercount;
136 volatile sig_atomic_t wresized;		/* Tty resized, when non-zero. */
137 unsigned short wrows;			/* Current number of tty rows. */
138 int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0;
139 int xflag = 0, zflag = 0;
140 
141 /* local function declarations */
142 static void usage(void);
143 static void needhdr(int signo);
144 static void needresize(int signo);
145 static void doresize(void);
146 static void phdr(void);
147 static void devstats(int perf_select, long double etime, int havelast);
148 static void cpustats(void);
149 static int readvar(kvm_t *kd, const char *name, int nlid, void *ptr,
150 		   size_t len);
151 
152 static void
153 usage(void)
154 {
155 	/*
156 	 * We also support the following 'traditional' syntax:
157 	 * iostat [drives] [wait [count]]
158 	 * This isn't mentioned in the man page, or the usage statement,
159 	 * but it is supported.
160 	 */
161 	fprintf(stderr, "usage: iostat [-CdhIKoTxz?] [-c count] [-M core]"
162 		" [-n devs] [-N system]\n"
163 		"\t      [-t type,if,pass] [-w wait] [drives]\n");
164 }
165 
166 int
167 main(int argc, char **argv)
168 {
169 	int c, i;
170 	int tflag = 0, hflag = 0, cflag = 0, wflag = 0, nflag = 0;
171 	int count = 0, waittime = 0;
172 	char *memf = NULL, *nlistf = NULL;
173 	struct devstat_match *matches;
174 	int num_matches = 0;
175 	char errbuf[_POSIX2_LINE_MAX];
176 	kvm_t *kd = NULL;
177 	long generation;
178 	int num_devices_specified;
179 	int num_selected, num_selections;
180 	long select_generation;
181 	char **specified_devices;
182 	devstat_select_mode select_mode;
183 	float f;
184 	int havelast = 0;
185 
186 	matches = NULL;
187 	maxshowdevs = 3;
188 
189 	while ((c = getopt(argc, argv, "c:CdhIKM:n:N:ot:Tw:xz?")) != -1) {
190 		switch(c) {
191 			case 'c':
192 				cflag++;
193 				count = atoi(optarg);
194 				if (count < 1)
195 					errx(1, "count %d is < 1", count);
196 				break;
197 			case 'C':
198 				Cflag++;
199 				break;
200 			case 'd':
201 				dflag++;
202 				break;
203 			case 'h':
204 				hflag++;
205 				break;
206 			case 'I':
207 				Iflag++;
208 				break;
209 			case 'K':
210 				Kflag++;
211 				break;
212 			case 'M':
213 				memf = optarg;
214 				break;
215 			case 'n':
216 				nflag++;
217 				maxshowdevs = atoi(optarg);
218 				if (maxshowdevs < 0)
219 					errx(1, "number of devices %d is < 0",
220 					     maxshowdevs);
221 				break;
222 			case 'N':
223 				nlistf = optarg;
224 				break;
225 			case 'o':
226 				oflag++;
227 				break;
228 			case 't':
229 				tflag++;
230 				if (devstat_buildmatch(optarg, &matches,
231 						       &num_matches) != 0)
232 					errx(1, "%s", devstat_errbuf);
233 				break;
234 			case 'T':
235 				Tflag++;
236 				break;
237 			case 'w':
238 				wflag++;
239 				f = atof(optarg);
240 				waittime = f * 1000;
241 				if (waittime < 1)
242 					errx(1, "wait time is < 1ms");
243 				break;
244 			case 'x':
245 				xflag++;
246 				break;
247 			case 'z':
248 				zflag++;
249 				break;
250 			default:
251 				usage();
252 				exit(1);
253 				break;
254 		}
255 	}
256 
257 	argc -= optind;
258 	argv += optind;
259 
260 	if (nlistf != NULL || memf != NULL) {
261 		kd = kvm_openfiles(nlistf, memf, NULL, O_RDONLY, errbuf);
262 
263 		if (kd == NULL)
264 			errx(1, "kvm_openfiles: %s", errbuf);
265 
266 		if (kvm_nlist(kd, namelist) == -1)
267 			errx(1, "kvm_nlist: %s", kvm_geterr(kd));
268 	}
269 
270 	/*
271 	 * Make sure that the userland devstat version matches the kernel
272 	 * devstat version.  If not, exit and print a message informing
273 	 * the user of his mistake.
274 	 */
275 	if (devstat_checkversion(kd) < 0)
276 		errx(1, "%s", devstat_errbuf);
277 
278 	/*
279 	 * Make sure Tflag and/or Cflag are set if dflag == 0.  If dflag is
280 	 * greater than 0, they may be 0 or non-zero.
281 	 */
282 	if (dflag == 0 && xflag == 0) {
283 		Cflag = 1;
284 		Tflag = 1;
285 	}
286 
287 	/* find out how many devices we have */
288 	if ((num_devices = devstat_getnumdevs(kd)) < 0)
289 		err(1, "can't get number of devices");
290 
291 	/*
292 	 * Figure out how many devices we should display.
293 	 */
294 	if (nflag == 0) {
295 		if (xflag > 0)
296 			maxshowdevs = num_devices;
297 		else if (oflag > 0) {
298 			if ((dflag > 0) && (Cflag == 0) && (Tflag == 0))
299 				maxshowdevs = 5;
300 			else if ((dflag > 0) && (Tflag > 0) && (Cflag == 0))
301 				maxshowdevs = 5;
302 			else
303 				maxshowdevs = 4;
304 		} else {
305 			if ((dflag > 0) && (Cflag == 0))
306 				maxshowdevs = 4;
307 			else
308 				maxshowdevs = 3;
309 		}
310 	}
311 
312 	cur.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
313 	if (cur.dinfo == NULL)
314 		err(1, "calloc failed");
315 
316 	last.dinfo = (struct devinfo *)calloc(1, sizeof(struct devinfo));
317 	if (last.dinfo == NULL)
318 		err(1, "calloc failed");
319 
320 	/*
321 	 * Grab all the devices.  We don't look to see if the list has
322 	 * changed here, since it almost certainly has.  We only look for
323 	 * errors.
324 	 */
325 	if (devstat_getdevs(kd, &cur) == -1)
326 		errx(1, "%s", devstat_errbuf);
327 
328 	num_devices = cur.dinfo->numdevs;
329 	generation = cur.dinfo->generation;
330 
331 	/*
332 	 * If the user specified any devices on the command line, see if
333 	 * they are in the list of devices we have now.
334 	 */
335 	specified_devices = (char **)malloc(sizeof(char *));
336 	if (specified_devices == NULL)
337 		err(1, "malloc failed");
338 
339 	for (num_devices_specified = 0; *argv; ++argv) {
340 		if (isdigit(**argv))
341 			break;
342 		num_devices_specified++;
343 		specified_devices = (char **)realloc(specified_devices,
344 						     sizeof(char *) *
345 						     num_devices_specified);
346 		if (specified_devices == NULL)
347 			err(1, "realloc failed");
348 
349 		specified_devices[num_devices_specified - 1] = *argv;
350 
351 	}
352 	if (nflag == 0 && maxshowdevs < num_devices_specified)
353 		maxshowdevs = num_devices_specified;
354 
355 	dev_select = NULL;
356 
357 	if ((num_devices_specified == 0) && (num_matches == 0))
358 		select_mode = DS_SELECT_ADD;
359 	else
360 		select_mode = DS_SELECT_ONLY;
361 
362 	/*
363 	 * At this point, selectdevs will almost surely indicate that the
364 	 * device list has changed, so we don't look for return values of 0
365 	 * or 1.  If we get back -1, though, there is an error.
366 	 */
367 	if (devstat_selectdevs(&dev_select, &num_selected,
368 			       &num_selections, &select_generation, generation,
369 			       cur.dinfo->devices, num_devices, matches,
370 			       num_matches, specified_devices,
371 			       num_devices_specified, select_mode, maxshowdevs,
372 			       hflag) == -1)
373 		errx(1, "%s", devstat_errbuf);
374 
375 	/*
376 	 * Look for the traditional wait time and count arguments.
377 	 */
378 	if (*argv) {
379 		f = atof(*argv);
380 		waittime = f * 1000;
381 
382 		/* Let the user know he goofed, but keep going anyway */
383 		if (wflag != 0)
384 			warnx("discarding previous wait interval, using"
385 			      " %g instead", waittime / 1000.0);
386 		wflag++;
387 
388 		if (*++argv) {
389 			count = atoi(*argv);
390 			if (cflag != 0)
391 				warnx("discarding previous count, using %d"
392 				      " instead", count);
393 			cflag++;
394 		} else
395 			count = -1;
396 	}
397 
398 	/*
399 	 * If the user specified a count, but not an interval, we default
400 	 * to an interval of 1 second.
401 	 */
402 	if ((wflag == 0) && (cflag > 0))
403 		waittime = 1 * 1000;
404 
405 	/*
406 	 * If the user specified a wait time, but not a count, we want to
407 	 * go on ad infinitum.  This can be redundant if the user uses the
408 	 * traditional method of specifying the wait, since in that case we
409 	 * already set count = -1 above.  Oh well.
410 	 */
411 	if ((wflag > 0) && (cflag == 0))
412 		count = -1;
413 
414 	bzero(cur.cp_time, sizeof(cur.cp_time));
415 	cur.tk_nout = 0;
416 	cur.tk_nin = 0;
417 
418 	/*
419 	 * Set the snap time to the system boot time (ie: zero), so the
420 	 * stats are calculated since system boot.
421 	 */
422 	cur.snap_time = 0;
423 
424 	/*
425 	 * If the user stops the program (control-Z) and then resumes it,
426 	 * print out the header again.
427 	 */
428 	(void)signal(SIGCONT, needhdr);
429 
430 	/*
431 	 * If our standard output is a tty, then install a SIGWINCH handler
432 	 * and set wresized so that our first iteration through the main
433 	 * iostat loop will peek at the terminal's current rows to find out
434 	 * how many lines can fit in a screenful of output.
435 	 */
436 	if (isatty(fileno(stdout)) != 0) {
437 		wresized = 1;
438 		(void)signal(SIGWINCH, needresize);
439 	} else {
440 		wresized = 0;
441 		wrows = IOSTAT_DEFAULT_ROWS;
442 	}
443 
444 	for (headercount = 1;;) {
445 		struct devinfo *tmp_dinfo;
446 		long tmp;
447 		long double etime;
448 
449 		if (Tflag > 0) {
450 			if ((readvar(kd, "kern.tty_nin", X_TK_NIN, &cur.tk_nin,
451 			     sizeof(cur.tk_nin)) != 0)
452 			 || (readvar(kd, "kern.tty_nout", X_TK_NOUT,
453 			     &cur.tk_nout, sizeof(cur.tk_nout))!= 0)) {
454 				Tflag = 0;
455 				warnx("disabling TTY statistics");
456 			}
457 		 }
458 
459 		if (Cflag > 0) {
460 			if (kd == NULL) {
461 				if (readvar(kd, "kern.cp_time", 0,
462 				    &cur.cp_time, sizeof(cur.cp_time)) != 0)
463 					Cflag = 0;
464 			} else {
465 				if (kvm_getcptime(kd, cur.cp_time) < 0) {
466 					warnx("kvm_getcptime: %s",
467 					    kvm_geterr(kd));
468 					Cflag = 0;
469 				}
470 			}
471 			if (Cflag == 0)
472 				warnx("disabling CPU time statistics");
473 		}
474 
475 		if (!--headercount) {
476 			phdr();
477 			if (wresized != 0)
478 				doresize();
479 			headercount = wrows;
480 		}
481 
482 		tmp_dinfo = last.dinfo;
483 		last.dinfo = cur.dinfo;
484 		cur.dinfo = tmp_dinfo;
485 
486 		last.snap_time = cur.snap_time;
487 
488 		/*
489 		 * Here what we want to do is refresh our device stats.
490 		 * devstat_getdevs() returns 1 when the device list has changed.
491 		 * If the device list has changed, we want to go through
492 		 * the selection process again, in case a device that we
493 		 * were previously displaying has gone away.
494 		 */
495 		switch (devstat_getdevs(kd, &cur)) {
496 		case -1:
497 			errx(1, "%s", devstat_errbuf);
498 			break;
499 		case 1: {
500 			int retval;
501 
502 			num_devices = cur.dinfo->numdevs;
503 			generation = cur.dinfo->generation;
504 			retval = devstat_selectdevs(&dev_select, &num_selected,
505 						    &num_selections,
506 						    &select_generation,
507 						    generation,
508 						    cur.dinfo->devices,
509 						    num_devices, matches,
510 						    num_matches,
511 						    specified_devices,
512 						    num_devices_specified,
513 						    select_mode, maxshowdevs,
514 						    hflag);
515 			switch(retval) {
516 			case -1:
517 				errx(1, "%s", devstat_errbuf);
518 				break;
519 			case 1:
520 				phdr();
521 				if (wresized != 0)
522 					doresize();
523 				headercount = wrows;
524 				break;
525 			default:
526 				break;
527 			}
528 			break;
529 		}
530 		default:
531 			break;
532 		}
533 
534 		/*
535 		 * We only want to re-select devices if we're in 'top'
536 		 * mode.  This is the only mode where the devices selected
537 		 * could actually change.
538 		 */
539 		if (hflag > 0) {
540 			int retval;
541 			retval = devstat_selectdevs(&dev_select, &num_selected,
542 						    &num_selections,
543 						    &select_generation,
544 						    generation,
545 						    cur.dinfo->devices,
546 						    num_devices, matches,
547 						    num_matches,
548 						    specified_devices,
549 						    num_devices_specified,
550 						    select_mode, maxshowdevs,
551 						    hflag);
552 			switch(retval) {
553 			case -1:
554 				errx(1,"%s", devstat_errbuf);
555 				break;
556 			case 1:
557 				phdr();
558 				if (wresized != 0)
559 					doresize();
560 				headercount = wrows;
561 				break;
562 			default:
563 				break;
564 			}
565 		}
566 
567 		if (Tflag > 0) {
568 			tmp = cur.tk_nin;
569 			cur.tk_nin -= last.tk_nin;
570 			last.tk_nin = tmp;
571 			tmp = cur.tk_nout;
572 			cur.tk_nout -= last.tk_nout;
573 			last.tk_nout = tmp;
574 		}
575 
576 		etime = cur.snap_time - last.snap_time;
577 
578 		if (etime == 0.0)
579 			etime = 1.0;
580 
581 		for (i = 0; i < CPUSTATES; i++) {
582 			tmp = cur.cp_time[i];
583 			cur.cp_time[i] -= last.cp_time[i];
584 			last.cp_time[i] = tmp;
585 		}
586 
587 		if (xflag == 0 && Tflag > 0)
588 			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
589 			    cur.tk_nout / etime);
590 
591 		devstats(hflag, etime, havelast);
592 
593 		if (xflag == 0) {
594 			if (Cflag > 0)
595 				cpustats();
596 
597 			printf("\n");
598 		}
599 		fflush(stdout);
600 
601 		if (count >= 0 && --count <= 0)
602 			break;
603 
604 		usleep(waittime * 1000);
605 		havelast = 1;
606 	}
607 
608 	exit(0);
609 }
610 
611 /*
612  * Force a header to be prepended to the next output.
613  */
614 void
615 needhdr(int signo)
616 {
617 
618 	headercount = 1;
619 }
620 
621 /*
622  * When the terminal is resized, force an update of the maximum number of rows
623  * printed between each header repetition.  Then force a new header to be
624  * prepended to the next output.
625  */
626 void
627 needresize(int signo)
628 {
629 
630 	wresized = 1;
631 	headercount = 1;
632 }
633 
634 /*
635  * Update the global `wrows' count of terminal rows.
636  */
637 void
638 doresize(void)
639 {
640 	int status;
641 	struct winsize w;
642 
643 	for (;;) {
644 		status = ioctl(fileno(stdout), TIOCGWINSZ, &w);
645 		if (status == -1 && errno == EINTR)
646 			continue;
647 		else if (status == -1)
648 			err(1, "ioctl");
649 		if (w.ws_row > 3)
650 			wrows = w.ws_row - 3;
651 		else
652 			wrows = IOSTAT_DEFAULT_ROWS;
653 		break;
654 	}
655 
656 	/*
657 	 * Inhibit doresize() calls until we are rescheduled by SIGWINCH.
658 	 */
659 	wresized = 0;
660 }
661 
662 static void
663 phdr(void)
664 {
665 	int i, printed;
666 	char devbuf[256];
667 
668 	/*
669 	 * If xflag is set, we need a per-loop header, not a page header, so
670 	 * just return.  We'll print the header in devstats().
671 	 */
672 	if (xflag > 0)
673 		return;
674 
675 	if (Tflag > 0)
676 		(void)printf("       tty");
677 	for (i = 0, printed=0;(i < num_devices) && (printed < maxshowdevs);i++){
678 		int di;
679 		if ((dev_select[i].selected != 0)
680 		 && (dev_select[i].selected <= maxshowdevs)) {
681 			di = dev_select[i].position;
682 			snprintf(devbuf, sizeof(devbuf), "%s%d",
683 					    cur.dinfo->devices[di].device_name,
684 					    cur.dinfo->devices[di].unit_number);
685 			if (oflag > 0)
686 				(void)printf("%13.6s ", devbuf);
687 			else
688 				printf("%16.6s ", devbuf);
689 			printed++;
690 		}
691 	}
692 	if (Cflag > 0)
693 		(void)printf("            cpu\n");
694 	else
695 		(void)printf("\n");
696 
697 	if (Tflag > 0)
698 		(void)printf(" tin  tout");
699 
700 	for (i=0, printed = 0;(i < num_devices) && (printed < maxshowdevs);i++){
701 		if ((dev_select[i].selected != 0)
702 		 && (dev_select[i].selected <= maxshowdevs)) {
703 			if (oflag > 0) {
704 				if (Iflag == 0)
705 					(void)printf(" sps tps msps ");
706 				else
707 					(void)printf(" blk xfr msps ");
708 			} else {
709 				if (Iflag == 0)
710 					printf("  KB/t tps  MB/s ");
711 				else
712 					printf("  KB/t xfrs   MB ");
713 			}
714 			printed++;
715 		}
716 	}
717 	if (Cflag > 0)
718 		(void)printf(" us ni sy in id\n");
719 	else
720 		printf("\n");
721 
722 }
723 
724 static void
725 devstats(int perf_select, long double etime, int havelast)
726 {
727 	int dn;
728 	long double transfers_per_second, transfers_per_second_read, transfers_per_second_write;
729 	long double kb_per_transfer, mb_per_second, mb_per_second_read, mb_per_second_write;
730 	u_int64_t total_bytes, total_transfers, total_blocks;
731 	u_int64_t total_bytes_read, total_transfers_read;
732 	u_int64_t total_bytes_write, total_transfers_write;
733 	long double busy_pct;
734 	u_int64_t queue_len;
735 	long double total_mb;
736 	long double blocks_per_second, ms_per_transaction;
737 	int firstline = 1;
738 	char *devname;
739 
740 	if (xflag > 0) {
741 		printf("                        extended device statistics  ");
742 		if (Tflag > 0)
743 			printf("      tty ");
744 		if (Cflag > 0)
745 			printf("           cpu ");
746 		printf("\n");
747 		if (Iflag == 0)
748 			printf(
749 		"device     r/s   w/s    kr/s    kw/s qlen svc_t  %%b  "
750 			    );
751 		else
752 			printf(
753 		"device     r/i   w/i    kr/i    kw/i qlen svc_t  %%b  "
754 			    );
755 		if (Tflag > 0)
756 			printf("tin  tout ");
757 		if (Cflag > 0)
758 			printf("us ni sy in id ");
759 		printf("\n");
760 	}
761 
762 	for (dn = 0; dn < num_devices; dn++) {
763 		int di;
764 
765 		if (((perf_select == 0) && (dev_select[dn].selected == 0))
766 		 || (dev_select[dn].selected > maxshowdevs))
767 			continue;
768 
769 		di = dev_select[dn].position;
770 
771 		if (devstat_compute_statistics(&cur.dinfo->devices[di],
772 		    havelast ? &last.dinfo->devices[di] : NULL, etime,
773 		    DSM_TOTAL_BYTES, &total_bytes,
774 		    DSM_TOTAL_BYTES_READ, &total_bytes_read,
775 		    DSM_TOTAL_BYTES_WRITE, &total_bytes_write,
776 		    DSM_TOTAL_TRANSFERS, &total_transfers,
777 		    DSM_TOTAL_TRANSFERS_READ, &total_transfers_read,
778 		    DSM_TOTAL_TRANSFERS_WRITE, &total_transfers_write,
779 		    DSM_TOTAL_BLOCKS, &total_blocks,
780 		    DSM_KB_PER_TRANSFER, &kb_per_transfer,
781 		    DSM_TRANSFERS_PER_SECOND, &transfers_per_second,
782 		    DSM_TRANSFERS_PER_SECOND_READ, &transfers_per_second_read,
783 		    DSM_TRANSFERS_PER_SECOND_WRITE, &transfers_per_second_write,
784 		    DSM_MB_PER_SECOND, &mb_per_second,
785 		    DSM_MB_PER_SECOND_READ, &mb_per_second_read,
786 		    DSM_MB_PER_SECOND_WRITE, &mb_per_second_write,
787 		    DSM_BLOCKS_PER_SECOND, &blocks_per_second,
788 		    DSM_MS_PER_TRANSACTION, &ms_per_transaction,
789 		    DSM_BUSY_PCT, &busy_pct,
790 		    DSM_QUEUE_LENGTH, &queue_len,
791 		    DSM_NONE) != 0)
792 			errx(1, "%s", devstat_errbuf);
793 
794 		if (perf_select != 0) {
795 			dev_select[dn].bytes = total_bytes;
796 			if ((dev_select[dn].selected == 0)
797 			 || (dev_select[dn].selected > maxshowdevs))
798 				continue;
799 		}
800 
801 		if (Kflag > 0 || xflag > 0) {
802 			int block_size = cur.dinfo->devices[di].block_size;
803 			total_blocks = total_blocks * (block_size ?
804 						       block_size : 512) / 1024;
805 		}
806 
807 		if (xflag > 0) {
808 			if (asprintf(&devname, "%s%d",
809 			    cur.dinfo->devices[di].device_name,
810 			    cur.dinfo->devices[di].unit_number) == -1)
811 				err(1, "asprintf");
812 			/*
813 			 * If zflag is set, skip any devices with zero I/O.
814 			 */
815 			if (zflag == 0 || transfers_per_second_read > 0.05 ||
816 			    transfers_per_second_write > 0.05 ||
817 			    mb_per_second_read > ((long double).0005)/1024 ||
818 			    mb_per_second_write > ((long double).0005)/1024 ||
819 			    busy_pct > 0.5) {
820 				if (Iflag == 0)
821 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
822 					    devname, transfers_per_second_read,
823 					    transfers_per_second_write,
824 					    mb_per_second_read * 1024,
825 					    mb_per_second_write * 1024,
826 					    queue_len,
827 					    ms_per_transaction, busy_pct);
828 				else
829 					printf("%-8.8s %5.1Lf %5.1Lf %7.1Lf %7.1Lf %4qu %5.1Lf %3.0Lf ",
830 					    devname,
831 					    (long double)total_transfers_read,
832 					    (long double)total_transfers_write,
833 					    (long double)
834 					        total_bytes_read / 1024,
835 					    (long double)
836 					        total_bytes_write / 1024,
837 					    queue_len,
838 					    ms_per_transaction, busy_pct);
839 				if (firstline) {
840 					/*
841 					 * If this is the first device
842 					 * we're printing, also print
843 					 * CPU or TTY stats if requested.
844 					 */
845 					firstline = 0;
846 					if (Tflag > 0)
847 						printf("%4.0Lf%5.0Lf",
848 						    cur.tk_nin / etime,
849 						    cur.tk_nout / etime);
850 					if (Cflag > 0)
851 						cpustats();
852 				}
853 				printf("\n");
854 			}
855 			free(devname);
856 		} else if (oflag > 0) {
857 			int msdig = (ms_per_transaction < 100.0) ? 1 : 0;
858 
859 			if (Iflag == 0)
860 				printf("%4.0Lf%4.0Lf%5.*Lf ",
861 				       blocks_per_second,
862 				       transfers_per_second,
863 				       msdig,
864 				       ms_per_transaction);
865 			else
866 				printf("%4.1qu%4.1qu%5.*Lf ",
867 				       total_blocks,
868 				       total_transfers,
869 				       msdig,
870 				       ms_per_transaction);
871 		} else {
872 			if (Iflag == 0)
873 				printf(" %5.2Lf %3.0Lf %5.2Lf ",
874 				       kb_per_transfer,
875 				       transfers_per_second,
876 				       mb_per_second);
877 			else {
878 				total_mb = total_bytes;
879 				total_mb /= 1024 * 1024;
880 
881 				printf(" %5.2Lf %3.1qu %5.2Lf ",
882 				       kb_per_transfer,
883 				       total_transfers,
884 				       total_mb);
885 			}
886 		}
887 	}
888 	if (xflag > 0 && zflag > 0 && firstline == 1 &&
889 	    (Tflag > 0 || Cflag > 0)) {
890 		/*
891 		 * If zflag is set and we did not print any device
892 		 * lines I/O because they were all zero,
893 		 * print TTY/CPU stats.
894 		 */
895 		printf("%52s","");
896 		if (Tflag > 0)
897 			printf("%4.0Lf %5.0Lf", cur.tk_nin / etime,
898 			    cur.tk_nout / etime);
899 		if (Cflag > 0)
900 			cpustats();
901 		printf("\n");
902 	}
903 }
904 
905 static void
906 cpustats(void)
907 {
908 	int state;
909 	double time;
910 
911 	time = 0.0;
912 
913 	for (state = 0; state < CPUSTATES; ++state)
914 		time += cur.cp_time[state];
915 	for (state = 0; state < CPUSTATES; ++state)
916 		printf(" %2.0f",
917 		       rint(100. * cur.cp_time[state] / (time ? time : 1)));
918 }
919 
920 static int
921 readvar(kvm_t *kd, const char *name, int nlid, void *ptr, size_t len)
922 {
923 	if (kd != NULL) {
924 		ssize_t nbytes;
925 
926 		nbytes = kvm_read(kd, namelist[nlid].n_value, ptr, len);
927 
928 		if (nbytes < 0) {
929 			warnx("kvm_read(%s): %s", namelist[nlid].n_name,
930 			    kvm_geterr(kd));
931 			return (1);
932 		}
933 		if (nbytes != len) {
934 			warnx("kvm_read(%s): expected %zu bytes, got %zd bytes",
935 			      namelist[nlid].n_name, len, nbytes);
936 			return (1);
937 		}
938 	} else {
939 		size_t nlen = len;
940 
941 		if (sysctlbyname(name, ptr, &nlen, NULL, 0) == -1) {
942 			warn("sysctl(%s...) failed", name);
943 			return (1);
944 		}
945 		if (nlen != len) {
946 			warnx("sysctl(%s...): expected %lu, got %lu", name,
947 			      (unsigned long)len, (unsigned long)nlen);
948 			return (1);
949 		}
950 	}
951 	return (0);
952 }
953