1 /*
2  * Gather top-level ZFS pool and resilver/scan statistics and print using
3  * influxdb line protocol
4  * usage: [options] [pool_name]
5  * where options are:
6  *   --execd, -e           run in telegraf execd input plugin mode, [CR] on
7  *                         stdin causes a sample to be printed and wait for
8  *                         the next [CR]
9  *   --no-histograms, -n   don't print histogram data (reduces cardinality
10  *                         if you don't care about histograms)
11  *   --sum-histogram-buckets, -s sum histogram bucket values
12  *
13  * To integrate into telegraf use one of:
14  * 1. the `inputs.execd` plugin with the `--execd` option
15  * 2. the `inputs.exec` plugin to simply run with no options
16  *
17  * NOTE: libzfs is an unstable interface. YMMV.
18  *
19  * The design goals of this software include:
20  * + be as lightweight as possible
21  * + reduce the number of external dependencies as far as possible, hence
22  *   there is no dependency on a client library for managing the metric
23  *   collection -- info is printed, KISS
24  * + broken pools or kernel bugs can cause this process to hang in an
25  *   unkillable state. For this reason, it is best to keep the damage limited
26  *   to a small process like zpool_influxdb rather than a larger collector.
27  *
28  * Copyright 2018-2020 Richard Elling
29  *
30  * This software is dual-licensed MIT and CDDL.
31  *
32  * The MIT License (MIT)
33  *
34  * Permission is hereby granted, free of charge, to any person obtaining a copy
35  * of this software and associated documentation files (the "Software"), to deal
36  * in the Software without restriction, including without limitation the rights
37  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
38  * copies of the Software, and to permit persons to whom the Software is
39  * furnished to do so, subject to the following conditions:
40  *
41  * The above copyright notice and this permission notice shall be included in
42  * all copies or substantial portions of the Software.
43  *
44  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
45  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
46  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
47  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
48  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
49  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
50  * SOFTWARE.
51  *
52  * CDDL HEADER START
53  *
54  * The contents of this file are subject to the terms of the
55  * Common Development and Distribution License (the "License").
56  * You may not use this file except in compliance with the License.
57  *
58  * The contents of this file are subject to the terms of the
59  * Common Development and Distribution License Version 1.0 (CDDL-1.0).
60  * You can obtain a copy of the license from the top-level file
61  * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>.
62  * You may not use this file except in compliance with the license.
63  *
64  * See the License for the specific language governing permissions
65  * and limitations under the License.
66  *
67  * CDDL HEADER END
68  */
69 #include <string.h>
70 #include <getopt.h>
71 #include <stdio.h>
72 #include <stdint.h>
73 #include <inttypes.h>
74 #include <libzfs.h>
75 
76 #define	POOL_MEASUREMENT	"zpool_stats"
77 #define	SCAN_MEASUREMENT	"zpool_scan_stats"
78 #define	VDEV_MEASUREMENT	"zpool_vdev_stats"
79 #define	POOL_LATENCY_MEASUREMENT	"zpool_latency"
80 #define	POOL_QUEUE_MEASUREMENT	"zpool_vdev_queue"
81 #define	MIN_LAT_INDEX	10  /* minimum latency index 10 = 1024ns */
82 #define	POOL_IO_SIZE_MEASUREMENT	"zpool_io_size"
83 #define	MIN_SIZE_INDEX	9  /* minimum size index 9 = 512 bytes */
84 
85 /* global options */
86 int execd_mode = 0;
87 int no_histograms = 0;
88 int sum_histogram_buckets = 0;
89 char metric_data_type = 'u';
90 uint64_t metric_value_mask = UINT64_MAX;
91 uint64_t timestamp = 0;
92 int complained_about_sync = 0;
93 char *tags = "";
94 
95 typedef int (*stat_printer_f)(nvlist_t *, const char *, const char *);
96 
97 /*
98  * influxdb line protocol rules for escaping are important because the
99  * zpool name can include characters that need to be escaped
100  *
101  * caller is responsible for freeing result
102  */
103 static char *
104 escape_string(const char *s)
105 {
106 	const char *c;
107 	char *d;
108 	char *t = (char *)malloc(ZFS_MAX_DATASET_NAME_LEN * 2);
109 	if (t == NULL) {
110 		fprintf(stderr, "error: cannot allocate memory\n");
111 		exit(1);
112 	}
113 
114 	for (c = s, d = t; *c != '\0'; c++, d++) {
115 		switch (*c) {
116 		case ' ':
117 		case ',':
118 		case '=':
119 		case '\\':
120 			*d++ = '\\';
121 		default:
122 			*d = *c;
123 		}
124 	}
125 	*d = '\0';
126 	return (t);
127 }
128 
129 /*
130  * print key=value where value is a uint64_t
131  */
132 static void
133 print_kv(char *key, uint64_t value)
134 {
135 	printf("%s=%llu%c", key,
136 	    (u_longlong_t)value & metric_value_mask, metric_data_type);
137 }
138 
139 /*
140  * print_scan_status() prints the details as often seen in the "zpool status"
141  * output. However, unlike the zpool command, which is intended for humans,
142  * this output is suitable for long-term tracking in influxdb.
143  * TODO: update to include issued scan data
144  */
145 static int
146 print_scan_status(nvlist_t *nvroot, const char *pool_name)
147 {
148 	uint_t c;
149 	int64_t elapsed;
150 	uint64_t examined, pass_exam, paused_time, paused_ts, rate;
151 	uint64_t remaining_time;
152 	pool_scan_stat_t *ps = NULL;
153 	double pct_done;
154 	char *state[DSS_NUM_STATES] = {
155 	    "none", "scanning", "finished", "canceled"};
156 	char *func;
157 
158 	(void) nvlist_lookup_uint64_array(nvroot,
159 	    ZPOOL_CONFIG_SCAN_STATS,
160 	    (uint64_t **)&ps, &c);
161 
162 	/*
163 	 * ignore if there are no stats
164 	 */
165 	if (ps == NULL)
166 		return (0);
167 
168 	/*
169 	 * return error if state is bogus
170 	 */
171 	if (ps->pss_state >= DSS_NUM_STATES ||
172 	    ps->pss_func >= POOL_SCAN_FUNCS) {
173 		if (complained_about_sync % 1000 == 0) {
174 			fprintf(stderr, "error: cannot decode scan stats: "
175 			    "ZFS is out of sync with compiled zpool_influxdb");
176 			complained_about_sync++;
177 		}
178 		return (1);
179 	}
180 
181 	switch (ps->pss_func) {
182 	case POOL_SCAN_NONE:
183 		func = "none_requested";
184 		break;
185 	case POOL_SCAN_SCRUB:
186 		func = "scrub";
187 		break;
188 	case POOL_SCAN_RESILVER:
189 		func = "resilver";
190 		break;
191 #ifdef POOL_SCAN_REBUILD
192 	case POOL_SCAN_REBUILD:
193 		func = "rebuild";
194 		break;
195 #endif
196 	default:
197 		func = "scan";
198 	}
199 
200 	/* overall progress */
201 	examined = ps->pss_examined ? ps->pss_examined : 1;
202 	pct_done = 0.0;
203 	if (ps->pss_to_examine > 0)
204 		pct_done = 100.0 * examined / ps->pss_to_examine;
205 
206 #ifdef EZFS_SCRUB_PAUSED
207 	paused_ts = ps->pss_pass_scrub_pause;
208 	paused_time = ps->pss_pass_scrub_spent_paused;
209 #else
210 	paused_ts = 0;
211 	paused_time = 0;
212 #endif
213 
214 	/* calculations for this pass */
215 	if (ps->pss_state == DSS_SCANNING) {
216 		elapsed = (int64_t)time(NULL) - (int64_t)ps->pss_pass_start -
217 		    (int64_t)paused_time;
218 		elapsed = (elapsed > 0) ? elapsed : 1;
219 		pass_exam = ps->pss_pass_exam ? ps->pss_pass_exam : 1;
220 		rate = pass_exam / elapsed;
221 		rate = (rate > 0) ? rate : 1;
222 		remaining_time = ps->pss_to_examine - examined / rate;
223 	} else {
224 		elapsed =
225 		    (int64_t)ps->pss_end_time - (int64_t)ps->pss_pass_start -
226 		    (int64_t)paused_time;
227 		elapsed = (elapsed > 0) ? elapsed : 1;
228 		pass_exam = ps->pss_pass_exam ? ps->pss_pass_exam : 1;
229 		rate = pass_exam / elapsed;
230 		remaining_time = 0;
231 	}
232 	rate = rate ? rate : 1;
233 
234 	/* influxdb line protocol format: "tags metrics timestamp" */
235 	printf("%s%s,function=%s,name=%s,state=%s ",
236 	    SCAN_MEASUREMENT, tags, func, pool_name, state[ps->pss_state]);
237 	print_kv("end_ts", ps->pss_end_time);
238 	print_kv(",errors", ps->pss_errors);
239 	print_kv(",examined", examined);
240 	print_kv(",issued", ps->pss_issued);
241 	print_kv(",pass_examined", pass_exam);
242 	print_kv(",pass_issued", ps->pss_pass_issued);
243 	print_kv(",paused_ts", paused_ts);
244 	print_kv(",paused_t", paused_time);
245 	printf(",pct_done=%.2f", pct_done);
246 	print_kv(",processed", ps->pss_processed);
247 	print_kv(",rate", rate);
248 	print_kv(",remaining_t", remaining_time);
249 	print_kv(",start_ts", ps->pss_start_time);
250 	print_kv(",to_examine", ps->pss_to_examine);
251 	print_kv(",to_process", ps->pss_to_process);
252 	printf(" %llu\n", (u_longlong_t)timestamp);
253 	return (0);
254 }
255 
256 /*
257  * get a vdev name that corresponds to the top-level vdev names
258  * printed by `zpool status`
259  */
260 static char *
261 get_vdev_name(nvlist_t *nvroot, const char *parent_name)
262 {
263 	static char vdev_name[256];
264 	char *vdev_type = NULL;
265 	uint64_t vdev_id = 0;
266 
267 	if (nvlist_lookup_string(nvroot, ZPOOL_CONFIG_TYPE,
268 	    &vdev_type) != 0) {
269 		vdev_type = "unknown";
270 	}
271 	if (nvlist_lookup_uint64(
272 	    nvroot, ZPOOL_CONFIG_ID, &vdev_id) != 0) {
273 		vdev_id = UINT64_MAX;
274 	}
275 	if (parent_name == NULL) {
276 		(void) snprintf(vdev_name, sizeof (vdev_name), "%s",
277 		    vdev_type);
278 	} else {
279 		(void) snprintf(vdev_name, sizeof (vdev_name),
280 		    "%s/%s-%llu",
281 		    parent_name, vdev_type, (u_longlong_t)vdev_id);
282 	}
283 	return (vdev_name);
284 }
285 
286 /*
287  * get a string suitable for an influxdb tag that describes this vdev
288  *
289  * By default only the vdev hierarchical name is shown, separated by '/'
290  * If the vdev has an associated path, which is typical of leaf vdevs,
291  * then the path is added.
292  * It would be nice to have the devid instead of the path, but under
293  * Linux we cannot be sure a devid will exist and we'd rather have
294  * something than nothing, so we'll use path instead.
295  */
296 static char *
297 get_vdev_desc(nvlist_t *nvroot, const char *parent_name)
298 {
299 	static char vdev_desc[2 * MAXPATHLEN];
300 	char *vdev_type = NULL;
301 	uint64_t vdev_id = 0;
302 	char vdev_value[MAXPATHLEN];
303 	char *vdev_path = NULL;
304 	char *s, *t;
305 
306 	if (nvlist_lookup_string(nvroot, ZPOOL_CONFIG_TYPE, &vdev_type) != 0) {
307 		vdev_type = "unknown";
308 	}
309 	if (nvlist_lookup_uint64(nvroot, ZPOOL_CONFIG_ID, &vdev_id) != 0) {
310 		vdev_id = UINT64_MAX;
311 	}
312 	if (nvlist_lookup_string(
313 	    nvroot, ZPOOL_CONFIG_PATH, &vdev_path) != 0) {
314 		vdev_path = NULL;
315 	}
316 
317 	if (parent_name == NULL) {
318 		s = escape_string(vdev_type);
319 		(void) snprintf(vdev_value, sizeof (vdev_value), "vdev=%s", s);
320 		free(s);
321 	} else {
322 		s = escape_string((char *)parent_name);
323 		t = escape_string(vdev_type);
324 		(void) snprintf(vdev_value, sizeof (vdev_value),
325 		    "vdev=%s/%s-%llu", s, t, (u_longlong_t)vdev_id);
326 		free(s);
327 		free(t);
328 	}
329 	if (vdev_path == NULL) {
330 		(void) snprintf(vdev_desc, sizeof (vdev_desc), "%s",
331 		    vdev_value);
332 	} else {
333 		s = escape_string(vdev_path);
334 		(void) snprintf(vdev_desc, sizeof (vdev_desc), "path=%s,%s",
335 		    s, vdev_value);
336 		free(s);
337 	}
338 	return (vdev_desc);
339 }
340 
341 /*
342  * vdev summary stats are a combination of the data shown by
343  * `zpool status` and `zpool list -v`
344  */
345 static int
346 print_summary_stats(nvlist_t *nvroot, const char *pool_name,
347     const char *parent_name)
348 {
349 	uint_t c;
350 	vdev_stat_t *vs;
351 	char *vdev_desc = NULL;
352 	vdev_desc = get_vdev_desc(nvroot, parent_name);
353 	if (nvlist_lookup_uint64_array(nvroot, ZPOOL_CONFIG_VDEV_STATS,
354 	    (uint64_t **)&vs, &c) != 0) {
355 		return (1);
356 	}
357 	printf("%s%s,name=%s,state=%s,%s ", POOL_MEASUREMENT, tags,
358 	    pool_name, zpool_state_to_name((vdev_state_t)vs->vs_state,
359 	    (vdev_aux_t)vs->vs_aux), vdev_desc);
360 	print_kv("alloc", vs->vs_alloc);
361 	print_kv(",free", vs->vs_space - vs->vs_alloc);
362 	print_kv(",size", vs->vs_space);
363 	print_kv(",read_bytes", vs->vs_bytes[ZIO_TYPE_READ]);
364 	print_kv(",read_errors", vs->vs_read_errors);
365 	print_kv(",read_ops", vs->vs_ops[ZIO_TYPE_READ]);
366 	print_kv(",write_bytes", vs->vs_bytes[ZIO_TYPE_WRITE]);
367 	print_kv(",write_errors", vs->vs_write_errors);
368 	print_kv(",write_ops", vs->vs_ops[ZIO_TYPE_WRITE]);
369 	print_kv(",checksum_errors", vs->vs_checksum_errors);
370 	print_kv(",fragmentation", vs->vs_fragmentation);
371 	printf(" %llu\n", (u_longlong_t)timestamp);
372 	return (0);
373 }
374 
375 /*
376  * vdev latency stats are histograms stored as nvlist arrays of uint64.
377  * Latency stats include the ZIO scheduler classes plus lower-level
378  * vdev latencies.
379  *
380  * In many cases, the top-level "root" view obscures the underlying
381  * top-level vdev operations. For example, if a pool has a log, special,
382  * or cache device, then each can behave very differently. It is useful
383  * to see how each is responding.
384  */
385 static int
386 print_vdev_latency_stats(nvlist_t *nvroot, const char *pool_name,
387     const char *parent_name)
388 {
389 	uint_t c, end = 0;
390 	nvlist_t *nv_ex;
391 	char *vdev_desc = NULL;
392 
393 	/* short_names become part of the metric name and are influxdb-ready */
394 	struct lat_lookup {
395 	    char *name;
396 	    char *short_name;
397 	    uint64_t sum;
398 	    uint64_t *array;
399 	};
400 	struct lat_lookup lat_type[] = {
401 	    {ZPOOL_CONFIG_VDEV_TOT_R_LAT_HISTO,   "total_read", 0},
402 	    {ZPOOL_CONFIG_VDEV_TOT_W_LAT_HISTO,   "total_write", 0},
403 	    {ZPOOL_CONFIG_VDEV_DISK_R_LAT_HISTO,  "disk_read", 0},
404 	    {ZPOOL_CONFIG_VDEV_DISK_W_LAT_HISTO,  "disk_write", 0},
405 	    {ZPOOL_CONFIG_VDEV_SYNC_R_LAT_HISTO,  "sync_read", 0},
406 	    {ZPOOL_CONFIG_VDEV_SYNC_W_LAT_HISTO,  "sync_write", 0},
407 	    {ZPOOL_CONFIG_VDEV_ASYNC_R_LAT_HISTO, "async_read", 0},
408 	    {ZPOOL_CONFIG_VDEV_ASYNC_W_LAT_HISTO, "async_write", 0},
409 	    {ZPOOL_CONFIG_VDEV_SCRUB_LAT_HISTO,   "scrub", 0},
410 #ifdef ZPOOL_CONFIG_VDEV_TRIM_LAT_HISTO
411 	    {ZPOOL_CONFIG_VDEV_TRIM_LAT_HISTO,    "trim", 0},
412 #endif
413 	    {NULL,	NULL}
414 	};
415 
416 	if (nvlist_lookup_nvlist(nvroot,
417 	    ZPOOL_CONFIG_VDEV_STATS_EX, &nv_ex) != 0) {
418 		return (6);
419 	}
420 
421 	vdev_desc = get_vdev_desc(nvroot, parent_name);
422 
423 	for (int i = 0; lat_type[i].name; i++) {
424 		if (nvlist_lookup_uint64_array(nv_ex,
425 		    lat_type[i].name, &lat_type[i].array, &c) != 0) {
426 			fprintf(stderr, "error: can't get %s\n",
427 			    lat_type[i].name);
428 			return (3);
429 		}
430 		/* end count count, all of the arrays are the same size */
431 		end = c - 1;
432 	}
433 
434 	for (int bucket = 0; bucket <= end; bucket++) {
435 		if (bucket < MIN_LAT_INDEX) {
436 			/* don't print, but collect the sum */
437 			for (int i = 0; lat_type[i].name; i++) {
438 				lat_type[i].sum += lat_type[i].array[bucket];
439 			}
440 			continue;
441 		}
442 		if (bucket < end) {
443 			printf("%s%s,le=%0.6f,name=%s,%s ",
444 			    POOL_LATENCY_MEASUREMENT, tags,
445 			    (float)(1ULL << bucket) * 1e-9,
446 			    pool_name, vdev_desc);
447 		} else {
448 			printf("%s%s,le=+Inf,name=%s,%s ",
449 			    POOL_LATENCY_MEASUREMENT, tags, pool_name,
450 			    vdev_desc);
451 		}
452 		for (int i = 0; lat_type[i].name; i++) {
453 			if (bucket <= MIN_LAT_INDEX || sum_histogram_buckets) {
454 				lat_type[i].sum += lat_type[i].array[bucket];
455 			} else {
456 				lat_type[i].sum = lat_type[i].array[bucket];
457 			}
458 			print_kv(lat_type[i].short_name, lat_type[i].sum);
459 			if (lat_type[i + 1].name != NULL) {
460 				printf(",");
461 			}
462 		}
463 		printf(" %llu\n", (u_longlong_t)timestamp);
464 	}
465 	return (0);
466 }
467 
468 /*
469  * vdev request size stats are histograms stored as nvlist arrays of uint64.
470  * Request size stats include the ZIO scheduler classes plus lower-level
471  * vdev sizes. Both independent (ind) and aggregated (agg) sizes are reported.
472  *
473  * In many cases, the top-level "root" view obscures the underlying
474  * top-level vdev operations. For example, if a pool has a log, special,
475  * or cache device, then each can behave very differently. It is useful
476  * to see how each is responding.
477  */
478 static int
479 print_vdev_size_stats(nvlist_t *nvroot, const char *pool_name,
480     const char *parent_name)
481 {
482 	uint_t c, end = 0;
483 	nvlist_t *nv_ex;
484 	char *vdev_desc = NULL;
485 
486 	/* short_names become the field name */
487 	struct size_lookup {
488 	    char *name;
489 	    char *short_name;
490 	    uint64_t sum;
491 	    uint64_t *array;
492 	};
493 	struct size_lookup size_type[] = {
494 	    {ZPOOL_CONFIG_VDEV_SYNC_IND_R_HISTO,   "sync_read_ind"},
495 	    {ZPOOL_CONFIG_VDEV_SYNC_IND_W_HISTO,   "sync_write_ind"},
496 	    {ZPOOL_CONFIG_VDEV_ASYNC_IND_R_HISTO,  "async_read_ind"},
497 	    {ZPOOL_CONFIG_VDEV_ASYNC_IND_W_HISTO,  "async_write_ind"},
498 	    {ZPOOL_CONFIG_VDEV_IND_SCRUB_HISTO,    "scrub_read_ind"},
499 	    {ZPOOL_CONFIG_VDEV_SYNC_AGG_R_HISTO,   "sync_read_agg"},
500 	    {ZPOOL_CONFIG_VDEV_SYNC_AGG_W_HISTO,   "sync_write_agg"},
501 	    {ZPOOL_CONFIG_VDEV_ASYNC_AGG_R_HISTO,  "async_read_agg"},
502 	    {ZPOOL_CONFIG_VDEV_ASYNC_AGG_W_HISTO,  "async_write_agg"},
503 	    {ZPOOL_CONFIG_VDEV_AGG_SCRUB_HISTO,    "scrub_read_agg"},
504 #ifdef ZPOOL_CONFIG_VDEV_IND_TRIM_HISTO
505 	    {ZPOOL_CONFIG_VDEV_IND_TRIM_HISTO,    "trim_write_ind"},
506 	    {ZPOOL_CONFIG_VDEV_AGG_TRIM_HISTO,    "trim_write_agg"},
507 #endif
508 	    {NULL,	NULL}
509 	};
510 
511 	if (nvlist_lookup_nvlist(nvroot,
512 	    ZPOOL_CONFIG_VDEV_STATS_EX, &nv_ex) != 0) {
513 		return (6);
514 	}
515 
516 	vdev_desc = get_vdev_desc(nvroot, parent_name);
517 
518 	for (int i = 0; size_type[i].name; i++) {
519 		if (nvlist_lookup_uint64_array(nv_ex, size_type[i].name,
520 		    &size_type[i].array, &c) != 0) {
521 			fprintf(stderr, "error: can't get %s\n",
522 			    size_type[i].name);
523 			return (3);
524 		}
525 		/* end count count, all of the arrays are the same size */
526 		end = c - 1;
527 	}
528 
529 	for (int bucket = 0; bucket <= end; bucket++) {
530 		if (bucket < MIN_SIZE_INDEX) {
531 			/* don't print, but collect the sum */
532 			for (int i = 0; size_type[i].name; i++) {
533 				size_type[i].sum += size_type[i].array[bucket];
534 			}
535 			continue;
536 		}
537 
538 		if (bucket < end) {
539 			printf("%s%s,le=%llu,name=%s,%s ",
540 			    POOL_IO_SIZE_MEASUREMENT, tags, 1ULL << bucket,
541 			    pool_name, vdev_desc);
542 		} else {
543 			printf("%s%s,le=+Inf,name=%s,%s ",
544 			    POOL_IO_SIZE_MEASUREMENT, tags, pool_name,
545 			    vdev_desc);
546 		}
547 		for (int i = 0; size_type[i].name; i++) {
548 			if (bucket <= MIN_SIZE_INDEX || sum_histogram_buckets) {
549 				size_type[i].sum += size_type[i].array[bucket];
550 			} else {
551 				size_type[i].sum = size_type[i].array[bucket];
552 			}
553 			print_kv(size_type[i].short_name, size_type[i].sum);
554 			if (size_type[i + 1].name != NULL) {
555 				printf(",");
556 			}
557 		}
558 		printf(" %llu\n", (u_longlong_t)timestamp);
559 	}
560 	return (0);
561 }
562 
563 /*
564  * ZIO scheduler queue stats are stored as gauges. This is unfortunate
565  * because the values can change very rapidly and any point-in-time
566  * value will quickly be obsoleted. It is also not easy to downsample.
567  * Thus only the top-level queue stats might be beneficial... maybe.
568  */
569 static int
570 print_queue_stats(nvlist_t *nvroot, const char *pool_name,
571     const char *parent_name)
572 {
573 	nvlist_t *nv_ex;
574 	uint64_t value;
575 
576 	/* short_names are used for the field name */
577 	struct queue_lookup {
578 	    char *name;
579 	    char *short_name;
580 	};
581 	struct queue_lookup queue_type[] = {
582 	    {ZPOOL_CONFIG_VDEV_SYNC_R_ACTIVE_QUEUE,	"sync_r_active"},
583 	    {ZPOOL_CONFIG_VDEV_SYNC_W_ACTIVE_QUEUE,	"sync_w_active"},
584 	    {ZPOOL_CONFIG_VDEV_ASYNC_R_ACTIVE_QUEUE,	"async_r_active"},
585 	    {ZPOOL_CONFIG_VDEV_ASYNC_W_ACTIVE_QUEUE,	"async_w_active"},
586 	    {ZPOOL_CONFIG_VDEV_SCRUB_ACTIVE_QUEUE,	"async_scrub_active"},
587 	    {ZPOOL_CONFIG_VDEV_SYNC_R_PEND_QUEUE,	"sync_r_pend"},
588 	    {ZPOOL_CONFIG_VDEV_SYNC_W_PEND_QUEUE,	"sync_w_pend"},
589 	    {ZPOOL_CONFIG_VDEV_ASYNC_R_PEND_QUEUE,	"async_r_pend"},
590 	    {ZPOOL_CONFIG_VDEV_ASYNC_W_PEND_QUEUE,	"async_w_pend"},
591 	    {ZPOOL_CONFIG_VDEV_SCRUB_PEND_QUEUE,	"async_scrub_pend"},
592 	    {NULL,	NULL}
593 	};
594 
595 	if (nvlist_lookup_nvlist(nvroot,
596 	    ZPOOL_CONFIG_VDEV_STATS_EX, &nv_ex) != 0) {
597 		return (6);
598 	}
599 
600 	printf("%s%s,name=%s,%s ", POOL_QUEUE_MEASUREMENT, tags, pool_name,
601 	    get_vdev_desc(nvroot, parent_name));
602 	for (int i = 0; queue_type[i].name; i++) {
603 		if (nvlist_lookup_uint64(nv_ex,
604 		    queue_type[i].name, &value) != 0) {
605 			fprintf(stderr, "error: can't get %s\n",
606 			    queue_type[i].name);
607 			return (3);
608 		}
609 		print_kv(queue_type[i].short_name, value);
610 		if (queue_type[i + 1].name != NULL) {
611 			printf(",");
612 		}
613 	}
614 	printf(" %llu\n", (u_longlong_t)timestamp);
615 	return (0);
616 }
617 
618 /*
619  * top-level vdev stats are at the pool level
620  */
621 static int
622 print_top_level_vdev_stats(nvlist_t *nvroot, const char *pool_name)
623 {
624 	nvlist_t *nv_ex;
625 	uint64_t value;
626 
627 	/* short_names become part of the metric name */
628 	struct queue_lookup {
629 	    char *name;
630 	    char *short_name;
631 	};
632 	struct queue_lookup queue_type[] = {
633 	    {ZPOOL_CONFIG_VDEV_SYNC_R_ACTIVE_QUEUE, "sync_r_active_queue"},
634 	    {ZPOOL_CONFIG_VDEV_SYNC_W_ACTIVE_QUEUE, "sync_w_active_queue"},
635 	    {ZPOOL_CONFIG_VDEV_ASYNC_R_ACTIVE_QUEUE, "async_r_active_queue"},
636 	    {ZPOOL_CONFIG_VDEV_ASYNC_W_ACTIVE_QUEUE, "async_w_active_queue"},
637 	    {ZPOOL_CONFIG_VDEV_SCRUB_ACTIVE_QUEUE, "async_scrub_active_queue"},
638 	    {ZPOOL_CONFIG_VDEV_SYNC_R_PEND_QUEUE, "sync_r_pend_queue"},
639 	    {ZPOOL_CONFIG_VDEV_SYNC_W_PEND_QUEUE, "sync_w_pend_queue"},
640 	    {ZPOOL_CONFIG_VDEV_ASYNC_R_PEND_QUEUE, "async_r_pend_queue"},
641 	    {ZPOOL_CONFIG_VDEV_ASYNC_W_PEND_QUEUE, "async_w_pend_queue"},
642 	    {ZPOOL_CONFIG_VDEV_SCRUB_PEND_QUEUE, "async_scrub_pend_queue"},
643 	    {NULL, NULL}
644 	};
645 
646 	if (nvlist_lookup_nvlist(nvroot,
647 	    ZPOOL_CONFIG_VDEV_STATS_EX, &nv_ex) != 0) {
648 		return (6);
649 	}
650 
651 	printf("%s%s,name=%s,vdev=root ", VDEV_MEASUREMENT, tags,
652 	    pool_name);
653 	for (int i = 0; queue_type[i].name; i++) {
654 		if (nvlist_lookup_uint64(nv_ex,
655 		    queue_type[i].name, &value) != 0) {
656 			fprintf(stderr, "error: can't get %s\n",
657 			    queue_type[i].name);
658 			return (3);
659 		}
660 		if (i > 0)
661 			printf(",");
662 		print_kv(queue_type[i].short_name, value);
663 	}
664 
665 	printf(" %llu\n", (u_longlong_t)timestamp);
666 	return (0);
667 }
668 
669 /*
670  * recursive stats printer
671  */
672 static int
673 print_recursive_stats(stat_printer_f func, nvlist_t *nvroot,
674     const char *pool_name, const char *parent_name, int descend)
675 {
676 	uint_t c, children;
677 	nvlist_t **child;
678 	char vdev_name[256];
679 	int err;
680 
681 	err = func(nvroot, pool_name, parent_name);
682 	if (err)
683 		return (err);
684 
685 	if (descend && nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
686 	    &child, &children) == 0) {
687 		(void) strncpy(vdev_name, get_vdev_name(nvroot, parent_name),
688 		    sizeof (vdev_name));
689 		vdev_name[sizeof (vdev_name) - 1] = '\0';
690 
691 		for (c = 0; c < children; c++) {
692 			print_recursive_stats(func, child[c], pool_name,
693 			    vdev_name, descend);
694 		}
695 	}
696 	return (0);
697 }
698 
699 /*
700  * call-back to print the stats from the pool config
701  *
702  * Note: if the pool is broken, this can hang indefinitely and perhaps in an
703  * unkillable state.
704  */
705 static int
706 print_stats(zpool_handle_t *zhp, void *data)
707 {
708 	uint_t c;
709 	int err;
710 	boolean_t missing;
711 	nvlist_t *config, *nvroot;
712 	vdev_stat_t *vs;
713 	struct timespec tv;
714 	char *pool_name;
715 
716 	/* if not this pool return quickly */
717 	if (data &&
718 	    strncmp(data, zpool_get_name(zhp), ZFS_MAX_DATASET_NAME_LEN) != 0) {
719 		zpool_close(zhp);
720 		return (0);
721 	}
722 
723 	if (zpool_refresh_stats(zhp, &missing) != 0) {
724 		zpool_close(zhp);
725 		return (1);
726 	}
727 
728 	config = zpool_get_config(zhp, NULL);
729 	if (clock_gettime(CLOCK_REALTIME, &tv) != 0)
730 		timestamp = (uint64_t)time(NULL) * 1000000000;
731 	else
732 		timestamp =
733 		    ((uint64_t)tv.tv_sec * 1000000000) + (uint64_t)tv.tv_nsec;
734 
735 	if (nvlist_lookup_nvlist(
736 	    config, ZPOOL_CONFIG_VDEV_TREE, &nvroot) != 0) {
737 	zpool_close(zhp);
738 		return (2);
739 	}
740 	if (nvlist_lookup_uint64_array(nvroot, ZPOOL_CONFIG_VDEV_STATS,
741 	    (uint64_t **)&vs, &c) != 0) {
742 	zpool_close(zhp);
743 		return (3);
744 	}
745 
746 	pool_name = escape_string(zpool_get_name(zhp));
747 	err = print_recursive_stats(print_summary_stats, nvroot,
748 	    pool_name, NULL, 1);
749 	/* if any of these return an error, skip the rest */
750 	if (err == 0)
751 	err = print_top_level_vdev_stats(nvroot, pool_name);
752 
753 	if (no_histograms == 0) {
754 	if (err == 0)
755 		err = print_recursive_stats(print_vdev_latency_stats, nvroot,
756 		    pool_name, NULL, 1);
757 	if (err == 0)
758 		err = print_recursive_stats(print_vdev_size_stats, nvroot,
759 		    pool_name, NULL, 1);
760 	if (err == 0)
761 		err = print_recursive_stats(print_queue_stats, nvroot,
762 		    pool_name, NULL, 0);
763 	}
764 	if (err == 0)
765 		err = print_scan_status(nvroot, pool_name);
766 
767 	free(pool_name);
768 	zpool_close(zhp);
769 	return (err);
770 }
771 
772 static void
773 usage(char *name)
774 {
775 	fprintf(stderr, "usage: %s [--execd][--no-histograms]"
776 	    "[--sum-histogram-buckets] [--signed-int] [poolname]\n", name);
777 	exit(EXIT_FAILURE);
778 }
779 
780 int
781 main(int argc, char *argv[])
782 {
783 	int opt;
784 	int ret = 8;
785 	char *line = NULL;
786 	size_t len, tagslen = 0;
787 	struct option long_options[] = {
788 	    {"execd", no_argument, NULL, 'e'},
789 	    {"help", no_argument, NULL, 'h'},
790 	    {"no-histograms", no_argument, NULL, 'n'},
791 	    {"signed-int", no_argument, NULL, 'i'},
792 	    {"sum-histogram-buckets", no_argument, NULL, 's'},
793 	    {"tags", required_argument, NULL, 't'},
794 	    {0, 0, 0, 0}
795 	};
796 	while ((opt = getopt_long(
797 	    argc, argv, "ehinst:", long_options, NULL)) != -1) {
798 		switch (opt) {
799 		case 'e':
800 			execd_mode = 1;
801 			break;
802 		case 'i':
803 			metric_data_type = 'i';
804 			metric_value_mask = INT64_MAX;
805 			break;
806 		case 'n':
807 			no_histograms = 1;
808 			break;
809 		case 's':
810 			sum_histogram_buckets = 1;
811 			break;
812 		case 't':
813 			tagslen = strlen(optarg) + 2;
814 			tags = calloc(tagslen, 1);
815 			if (tags == NULL) {
816 				fprintf(stderr,
817 				    "error: cannot allocate memory "
818 				    "for tags\n");
819 				exit(1);
820 			}
821 			(void) snprintf(tags, tagslen, ",%s", optarg);
822 			break;
823 		default:
824 			usage(argv[0]);
825 		}
826 	}
827 
828 	libzfs_handle_t *g_zfs;
829 	if ((g_zfs = libzfs_init()) == NULL) {
830 		fprintf(stderr,
831 		    "error: cannot initialize libzfs. "
832 		    "Is the zfs module loaded or zrepl running?\n");
833 		exit(EXIT_FAILURE);
834 	}
835 	if (execd_mode == 0) {
836 		ret = zpool_iter(g_zfs, print_stats, argv[optind]);
837 		return (ret);
838 	}
839 	while (getline(&line, &len, stdin) != -1) {
840 		ret = zpool_iter(g_zfs, print_stats, argv[optind]);
841 		fflush(stdout);
842 	}
843 	return (ret);
844 }
845