1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 *
25 * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
26 */
27
28 #ifndef _SYS_KSTAT_H
29 #define _SYS_KSTAT_H
30
31 /*
32 * Definition of general kernel statistics structures and /dev/kstat ioctls
33 */
34
35 #include <sys/types.h>
36 #include <sys/time.h>
37
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41
42 typedef int kid_t; /* unique kstat id */
43
44 /*
45 * Kernel statistics driver (/dev/kstat) ioctls
46 */
47
48 #define KSTAT_IOC_BASE ('K' << 8)
49
50 #define KSTAT_IOC_CHAIN_ID KSTAT_IOC_BASE | 0x01
51 #define KSTAT_IOC_READ KSTAT_IOC_BASE | 0x02
52 #define KSTAT_IOC_WRITE KSTAT_IOC_BASE | 0x03
53
54 /*
55 * /dev/kstat ioctl usage (kd denotes /dev/kstat descriptor):
56 *
57 * kcid = ioctl(kd, KSTAT_IOC_CHAIN_ID, NULL);
58 * kcid = ioctl(kd, KSTAT_IOC_READ, kstat_t *);
59 * kcid = ioctl(kd, KSTAT_IOC_WRITE, kstat_t *);
60 */
61
62 #define KSTAT_STRLEN 31 /* 30 chars + NULL; must be 16 * n - 1 */
63
64 /*
65 * The generic kstat header
66 */
67
68 typedef struct kstat {
69 /*
70 * Fields relevant to both kernel and user
71 */
72 hrtime_t ks_crtime; /* creation time (from gethrtime()) */
73 struct kstat *ks_next; /* kstat chain linkage */
74 kid_t ks_kid; /* unique kstat ID */
75 char ks_module[KSTAT_STRLEN]; /* provider module name */
76 uchar_t ks_resv; /* reserved, currently just padding */
77 int ks_instance; /* provider module's instance */
78 char ks_name[KSTAT_STRLEN]; /* kstat name */
79 uchar_t ks_type; /* kstat data type */
80 char ks_class[KSTAT_STRLEN]; /* kstat class */
81 uchar_t ks_flags; /* kstat flags */
82 void *ks_data; /* kstat type-specific data */
83 uint_t ks_ndata; /* # of type-specific data records */
84 size_t ks_data_size; /* total size of kstat data section */
85 hrtime_t ks_snaptime; /* time of last data shapshot */
86 /*
87 * Fields relevant to kernel only
88 */
89 int (*ks_update)(struct kstat *, int); /* dynamic update */
90 void *ks_private; /* arbitrary provider-private data */
91 int (*ks_snapshot)(struct kstat *, void *, int);
92 void *ks_lock; /* protects this kstat's data */
93 } kstat_t;
94
95 #ifdef _SYSCALL32
96
97 typedef int32_t kid32_t;
98
99 typedef struct kstat32 {
100 /*
101 * Fields relevant to both kernel and user
102 */
103 hrtime_t ks_crtime;
104 caddr32_t ks_next; /* struct kstat pointer */
105 kid32_t ks_kid;
106 char ks_module[KSTAT_STRLEN];
107 uint8_t ks_resv;
108 int32_t ks_instance;
109 char ks_name[KSTAT_STRLEN];
110 uint8_t ks_type;
111 char ks_class[KSTAT_STRLEN];
112 uint8_t ks_flags;
113 caddr32_t ks_data; /* type-specific data */
114 uint32_t ks_ndata;
115 size32_t ks_data_size;
116 hrtime_t ks_snaptime;
117 /*
118 * Fields relevant to kernel only (only needed here for padding)
119 */
120 int32_t _ks_update;
121 caddr32_t _ks_private;
122 int32_t _ks_snapshot;
123 caddr32_t _ks_lock;
124 } kstat32_t;
125
126 #endif /* _SYSCALL32 */
127
128 /*
129 * kstat structure and locking strategy
130 *
131 * Each kstat consists of a header section (a kstat_t) and a data section.
132 * The system maintains a set of kstats, protected by kstat_chain_lock.
133 * kstat_chain_lock protects all additions to/deletions from this set,
134 * as well as all changes to kstat headers. kstat data sections are
135 * *optionally* protected by the per-kstat ks_lock. If ks_lock is non-NULL,
136 * kstat clients (e.g. /dev/kstat) will acquire this lock for all of their
137 * operations on that kstat. It is up to the kstat provider to decide whether
138 * guaranteeing consistent data to kstat clients is sufficiently important
139 * to justify the locking cost. Note, however, that most statistic updates
140 * already occur under one of the provider's mutexes, so if the provider sets
141 * ks_lock to point to that mutex, then kstat data locking is free.
142 *
143 * NOTE: variable-size kstats MUST employ kstat data locking, to prevent
144 * data-size races with kstat clients.
145 *
146 * NOTE: ks_lock is really of type (kmutex_t *); it is declared as (void *)
147 * in the kstat header so that users don't have to be exposed to all of the
148 * kernel's lock-related data structures.
149 */
150
151 #if defined(_KERNEL)
152
153 #define KSTAT_ENTER(k) \
154 { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_enter(lp); }
155
156 #define KSTAT_EXIT(k) \
157 { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_exit(lp); }
158
159 #define KSTAT_UPDATE(k, rw) (*(k)->ks_update)((k), (rw))
160
161 #define KSTAT_SNAPSHOT(k, buf, rw) (*(k)->ks_snapshot)((k), (buf), (rw))
162
163 #endif /* defined(_KERNEL) */
164
165 /*
166 * kstat time
167 *
168 * All times associated with kstats (e.g. creation time, snapshot time,
169 * kstat_timer_t and kstat_io_t timestamps, etc.) are 64-bit nanosecond values,
170 * as returned by gethrtime(). The accuracy of these timestamps is machine
171 * dependent, but the precision (units) is the same across all platforms.
172 */
173
174 /*
175 * kstat identity (KID)
176 *
177 * Each kstat is assigned a unique KID (kstat ID) when it is added to the
178 * global kstat chain. The KID is used as a cookie by /dev/kstat to
179 * request information about the corresponding kstat. There is also
180 * an identity associated with the entire kstat chain, kstat_chain_id,
181 * which is bumped each time a kstat is added or deleted. /dev/kstat uses
182 * the chain ID to detect changes in the kstat chain (e.g., a new disk
183 * coming online) between ioctl()s.
184 */
185
186 /*
187 * kstat module, kstat instance
188 *
189 * ks_module and ks_instance contain the name and instance of the module
190 * that created the kstat. In cases where there can only be one instance,
191 * ks_instance is 0. The kernel proper (/kernel/unix) uses "unix" as its
192 * module name.
193 */
194
195 /*
196 * kstat name
197 *
198 * ks_name gives a meaningful name to a kstat. The full kstat namespace
199 * is module.instance.name, so the name only need be unique within a
200 * module. kstat_create() will fail if you try to create a kstat with
201 * an already-used (ks_module, ks_instance, ks_name) triplet. Spaces are
202 * allowed in kstat names, but strongly discouraged, since they hinder
203 * awk-style processing at user level.
204 */
205
206 /*
207 * kstat type
208 *
209 * The kstat mechanism provides several flavors of kstat data, defined
210 * below. The "raw" kstat type is just treated as an array of bytes; you
211 * can use this to export any kind of data you want.
212 *
213 * Some kstat types allow multiple data structures per kstat, e.g.
214 * KSTAT_TYPE_NAMED; others do not. This is part of the spec for each
215 * kstat data type.
216 *
217 * User-level tools should *not* rely on the #define KSTAT_NUM_TYPES. To
218 * get this information, read out the standard system kstat "kstat_types".
219 */
220
221 #define KSTAT_TYPE_RAW 0 /* can be anything */
222 /* ks_ndata >= 1 */
223 #define KSTAT_TYPE_NAMED 1 /* name/value pair */
224 /* ks_ndata >= 1 */
225 #define KSTAT_TYPE_INTR 2 /* interrupt statistics */
226 /* ks_ndata == 1 */
227 #define KSTAT_TYPE_IO 3 /* I/O statistics */
228 /* ks_ndata == 1 */
229 #define KSTAT_TYPE_TIMER 4 /* event timer */
230 /* ks_ndata >= 1 */
231
232 #define KSTAT_NUM_TYPES 5
233
234 /*
235 * kstat class
236 *
237 * Each kstat can be characterized as belonging to some broad class
238 * of statistics, e.g. disk, tape, net, vm, streams, etc. This field
239 * can be used as a filter to extract related kstats. The following
240 * values are currently in use: disk, tape, net, controller, vm, kvm,
241 * hat, streams, kstat, and misc. (The kstat class encompasses things
242 * like kstat_types.)
243 */
244
245 /*
246 * kstat flags
247 *
248 * Any of the following flags may be passed to kstat_create(). They are
249 * all zero by default.
250 *
251 * KSTAT_FLAG_VIRTUAL:
252 *
253 * Tells kstat_create() not to allocate memory for the
254 * kstat data section; instead, you will set the ks_data
255 * field to point to the data you wish to export. This
256 * provides a convenient way to export existing data
257 * structures.
258 *
259 * KSTAT_FLAG_VAR_SIZE:
260 *
261 * The size of the kstat you are creating will vary over time.
262 * For example, you may want to use the kstat mechanism to
263 * export a linked list. NOTE: The kstat framework does not
264 * manage the data section, so all variable-size kstats must be
265 * virtual kstats. Moreover, variable-size kstats MUST employ
266 * kstat data locking to prevent data-size races with kstat
267 * clients. See the section on "kstat snapshot" for details.
268 *
269 * KSTAT_FLAG_WRITABLE:
270 *
271 * Makes the kstat's data section writable by root.
272 * The ks_snapshot routine (see below) does not need to check for
273 * this; permission checking is handled in the kstat driver.
274 *
275 * KSTAT_FLAG_PERSISTENT:
276 *
277 * Indicates that this kstat is to be persistent over time.
278 * For persistent kstats, kstat_delete() simply marks the
279 * kstat as dormant; a subsequent kstat_create() reactivates
280 * the kstat. This feature is provided so that statistics
281 * are not lost across driver close/open (e.g., raw disk I/O
282 * on a disk with no mounted partitions.)
283 * NOTE: Persistent kstats cannot be virtual, since ks_data
284 * points to garbage as soon as the driver goes away.
285 *
286 * The following flags are maintained by the kstat framework:
287 *
288 * KSTAT_FLAG_DORMANT:
289 *
290 * For persistent kstats, indicates that the kstat is in the
291 * dormant state (e.g., the corresponding device is closed).
292 *
293 * KSTAT_FLAG_INVALID:
294 *
295 * This flag is set when a kstat is in a transitional state,
296 * e.g. between kstat_create() and kstat_install().
297 * kstat clients must not attempt to access the kstat's data
298 * if this flag is set.
299 *
300 * KSTAT_FLAG_LONGSTRINGS:
301 *
302 * Indicates that this kstat contains long strings (which
303 * are stored outside of the kstat data section). When copied
304 * out to user space the string data will be held in the data
305 * section provided by the user.
306 */
307
308 #define KSTAT_FLAG_VIRTUAL 0x01
309 #define KSTAT_FLAG_VAR_SIZE 0x02
310 #define KSTAT_FLAG_WRITABLE 0x04
311 #define KSTAT_FLAG_PERSISTENT 0x08
312 #define KSTAT_FLAG_DORMANT 0x10
313 #define KSTAT_FLAG_INVALID 0x20
314 #define KSTAT_FLAG_LONGSTRINGS 0x40
315
316 /*
317 * Dynamic update support
318 *
319 * The kstat mechanism allows for an optional ks_update function to update
320 * kstat data. This is useful for drivers where the underlying device
321 * keeps cheap hardware stats, but extraction is expensive. Instead of
322 * constantly keeping the kstat data section up to date, you can supply a
323 * ks_update function which updates the kstat's data section on demand.
324 * To take advantage of this feature, simply set the ks_update field before
325 * calling kstat_install().
326 *
327 * The ks_update function, if supplied, must have the following structure:
328 *
329 * int
330 * foo_kstat_update(kstat_t *ksp, int rw)
331 * {
332 * if (rw == KSTAT_WRITE) {
333 * ... update the native stats from ksp->ks_data;
334 * return EACCES if you don't support this
335 * } else {
336 * ... update ksp->ks_data from the native stats
337 * }
338 * }
339 *
340 * The ks_update return codes are: 0 for success, EACCES if you don't allow
341 * KSTAT_WRITE, and EIO for any other type of error.
342 *
343 * In general, the ks_update function may need to refer to provider-private
344 * data; for example, it may need a pointer to the provider's raw statistics.
345 * The ks_private field is available for this purpose. Its use is entirely
346 * at the provider's discretion.
347 *
348 * All variable-size kstats MUST supply a ks_update routine, which computes
349 * and sets ks_data_size (and ks_ndata if that is meaningful), since these
350 * are needed to perform kstat snapshots (see below).
351 *
352 * No kstat locking should be done inside the ks_update routine. The caller
353 * will already be holding the kstat's ks_lock (to ensure consistent data).
354 */
355
356 #define KSTAT_READ 0
357 #define KSTAT_WRITE 1
358
359 /*
360 * Kstat snapshot
361 *
362 * In order to get a consistent view of a kstat's data, clients must obey
363 * the kstat's locking strategy. However, these clients may need to perform
364 * operations on the data which could cause a fault (e.g. copyout()), or
365 * operations which are simply expensive. Doing so could cause deadlock
366 * (e.g. if you're holding a disk's kstat lock which is ultimately required
367 * to resolve a copyout() fault), performance degradation (since the providers'
368 * activity is serialized at the kstat lock), device timing problems, etc.
369 *
370 * To avoid these problems, kstat data is provided via snapshots. Taking
371 * a snapshot is a simple process: allocate a wired-down kernel buffer,
372 * acquire the kstat's data lock, copy the data into the buffer ("take the
373 * snapshot"), and release the lock. This ensures that the kstat's data lock
374 * will be held as briefly as possible, and that no faults will occur while
375 * the lock is held.
376 *
377 * Normally, the snapshot is taken by default_kstat_snapshot(), which
378 * timestamps the data (sets ks_snaptime), copies it, and does a little
379 * massaging to deal with incomplete transactions on i/o kstats. However,
380 * this routine only works for kstats with contiguous data (the typical case).
381 * If you create a kstat whose data is, say, a linked list, you must provide
382 * your own ks_snapshot routine. The routine you supply must have the
383 * following prototype (replace "foo" with something appropriate):
384 *
385 * int foo_kstat_snapshot(kstat_t *ksp, void *buf, int rw);
386 *
387 * The minimal snapshot routine -- one which copies contiguous data that
388 * doesn't need any massaging -- would be this:
389 *
390 * ksp->ks_snaptime = gethrtime();
391 * if (rw == KSTAT_WRITE)
392 * bcopy(buf, ksp->ks_data, ksp->ks_data_size);
393 * else
394 * bcopy(ksp->ks_data, buf, ksp->ks_data_size);
395 * return (0);
396 *
397 * A more illuminating example is taking a snapshot of a linked list:
398 *
399 * ksp->ks_snaptime = gethrtime();
400 * if (rw == KSTAT_WRITE)
401 * return (EACCES); ... See below ...
402 * for (foo = first_foo; foo; foo = foo->next) {
403 * bcopy((char *) foo, (char *) buf, sizeof (struct foo));
404 * buf = ((struct foo *) buf) + 1;
405 * }
406 * return (0);
407 *
408 * In the example above, we have decided that we don't want to allow
409 * KSTAT_WRITE access, so we return EACCES if this is attempted.
410 *
411 * The key points are:
412 *
413 * (1) ks_snaptime must be set (via gethrtime()) to timestamp the data.
414 * (2) Data gets copied from the kstat to the buffer on KSTAT_READ,
415 * and from the buffer to the kstat on KSTAT_WRITE.
416 * (3) ks_snapshot return values are: 0 for success, EACCES if you
417 * don't allow KSTAT_WRITE, and EIO for any other type of error.
418 *
419 * Named kstats (see section on "Named statistics" below) containing long
420 * strings (KSTAT_DATA_STRING) need special handling. The kstat driver
421 * assumes that all strings are copied into the buffer after the array of
422 * named kstats, and the pointers (KSTAT_NAMED_STR_PTR()) are updated to point
423 * into the copy within the buffer. The default snapshot routine does this,
424 * but overriding routines should contain at least the following:
425 *
426 * if (rw == KSTAT_READ) {
427 * kstat_named_t *knp = buf;
428 * char *end = knp + ksp->ks_ndata;
429 * uint_t i;
430 *
431 * ... Do the regular copy ...
432 * bcopy(ksp->ks_data, buf, sizeof (kstat_named_t) * ksp->ks_ndata);
433 *
434 * for (i = 0; i < ksp->ks_ndata; i++, knp++) {
435 * if (knp[i].data_type == KSTAT_DATA_STRING &&
436 * KSTAT_NAMED_STR_PTR(knp) != NULL) {
437 * bcopy(KSTAT_NAMED_STR_PTR(knp), end,
438 * KSTAT_NAMED_STR_BUFLEN(knp));
439 * KSTAT_NAMED_STR_PTR(knp) = end;
440 * end += KSTAT_NAMED_STR_BUFLEN(knp);
441 * }
442 * }
443 */
444
445 /*
446 * Named statistics.
447 *
448 * List of arbitrary name=value statistics.
449 */
450
451 typedef struct kstat_named {
452 char name[KSTAT_STRLEN]; /* name of counter */
453 uchar_t data_type; /* data type */
454 union {
455 char c[16]; /* enough for 128-bit ints */
456 int32_t i32;
457 uint32_t ui32;
458 struct {
459 union {
460 char *ptr; /* NULL-term string */
461 #if defined(_KERNEL) && defined(_MULTI_DATAMODEL)
462 caddr32_t ptr32;
463 #endif
464 char __pad[8]; /* 64-bit padding */
465 } addr;
466 uint32_t len; /* # bytes for strlen + '\0' */
467 } str;
468 /*
469 * The int64_t and uint64_t types are not valid for a maximally conformant
470 * 32-bit compilation environment (cc -Xc) using compilers prior to the
471 * introduction of C99 conforming compiler (reference ISO/IEC 9899:1990).
472 * In these cases, the visibility of i64 and ui64 is only permitted for
473 * 64-bit compilation environments or 32-bit non-maximally conformant
474 * C89 or C90 ANSI C compilation environments (cc -Xt and cc -Xa). In the
475 * C99 ANSI C compilation environment, the long long type is supported.
476 * The _INT64_TYPE is defined by the implementation (see sys/int_types.h).
477 */
478 #if defined(_INT64_TYPE)
479 int64_t i64;
480 uint64_t ui64;
481 #endif
482 long l;
483 ulong_t ul;
484
485 /* These structure members are obsolete */
486
487 longlong_t ll;
488 u_longlong_t ull;
489 float f;
490 double d;
491 } value; /* value of counter */
492 } kstat_named_t;
493
494 #define KSTAT_DATA_CHAR 0
495 #define KSTAT_DATA_INT32 1
496 #define KSTAT_DATA_UINT32 2
497 #define KSTAT_DATA_INT64 3
498 #define KSTAT_DATA_UINT64 4
499
500 #if !defined(_LP64)
501 #define KSTAT_DATA_LONG KSTAT_DATA_INT32
502 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT32
503 #else
504 #if !defined(_KERNEL)
505 #define KSTAT_DATA_LONG KSTAT_DATA_INT64
506 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT64
507 #else
508 #define KSTAT_DATA_LONG 7 /* only visible to the kernel */
509 #define KSTAT_DATA_ULONG 8 /* only visible to the kernel */
510 #endif /* !_KERNEL */
511 #endif /* !_LP64 */
512
513 /*
514 * Statistics exporting named kstats with long strings (KSTAT_DATA_STRING)
515 * may not make the assumption that ks_data_size is equal to (ks_ndata * sizeof
516 * (kstat_named_t)). ks_data_size in these cases is equal to the sum of the
517 * amount of space required to store the strings (ie, the sum of
518 * KSTAT_NAMED_STR_BUFLEN() for all KSTAT_DATA_STRING statistics) plus the
519 * space required to store the kstat_named_t's.
520 *
521 * The default update routine will update ks_data_size automatically for
522 * variable-length kstats containing long strings (using the default update
523 * routine only makes sense if the string is the only thing that is changing
524 * in size, and ks_ndata is constant). Fixed-length kstats containing long
525 * strings must explicitly change ks_data_size (after creation but before
526 * initialization) to reflect the correct amount of space required for the
527 * long strings and the kstat_named_t's.
528 */
529 #define KSTAT_DATA_STRING 9
530
531 /* These types are obsolete */
532
533 #define KSTAT_DATA_LONGLONG KSTAT_DATA_INT64
534 #define KSTAT_DATA_ULONGLONG KSTAT_DATA_UINT64
535 #define KSTAT_DATA_FLOAT 5
536 #define KSTAT_DATA_DOUBLE 6
537
538 #define KSTAT_NAMED_PTR(kptr) ((kstat_named_t *)(kptr)->ks_data)
539
540 /*
541 * Retrieve the pointer of the string contained in the given named kstat.
542 */
543 #define KSTAT_NAMED_STR_PTR(knptr) ((knptr)->value.str.addr.ptr)
544
545 /*
546 * Retrieve the length of the buffer required to store the string in the given
547 * named kstat.
548 */
549 #define KSTAT_NAMED_STR_BUFLEN(knptr) ((knptr)->value.str.len)
550
551 /*
552 * Interrupt statistics.
553 *
554 * An interrupt is a hard interrupt (sourced from the hardware device
555 * itself), a soft interrupt (induced by the system via the use of
556 * some system interrupt source), a watchdog interrupt (induced by
557 * a periodic timer call), spurious (an interrupt entry point was
558 * entered but there was no interrupt condition to service),
559 * or multiple service (an interrupt condition was detected and
560 * serviced just prior to returning from any of the other types).
561 *
562 * Measurement of the spurious class of interrupts is useful for
563 * autovectored devices in order to pinpoint any interrupt latency
564 * problems in a particular system configuration.
565 *
566 * Devices that have more than one interrupt of the same
567 * type should use multiple structures.
568 */
569
570 #define KSTAT_INTR_HARD 0
571 #define KSTAT_INTR_SOFT 1
572 #define KSTAT_INTR_WATCHDOG 2
573 #define KSTAT_INTR_SPURIOUS 3
574 #define KSTAT_INTR_MULTSVC 4
575
576 #define KSTAT_NUM_INTRS 5
577
578 typedef struct kstat_intr {
579 uint_t intrs[KSTAT_NUM_INTRS]; /* interrupt counters */
580 } kstat_intr_t;
581
582 #define KSTAT_INTR_PTR(kptr) ((kstat_intr_t *)(kptr)->ks_data)
583
584 /*
585 * I/O statistics.
586 */
587
588 typedef struct kstat_io {
589
590 /*
591 * Basic counters.
592 *
593 * The counters should be updated at the end of service
594 * (e.g., just prior to calling biodone()).
595 */
596
597 u_longlong_t nread; /* number of bytes read */
598 u_longlong_t nwritten; /* number of bytes written */
599 uint_t reads; /* number of read operations */
600 uint_t writes; /* number of write operations */
601
602 /*
603 * Accumulated time and queue length statistics.
604 *
605 * Accumulated time statistics are kept as a running sum
606 * of "active" time. Queue length statistics are kept as a
607 * running sum of the product of queue length and elapsed time
608 * at that length -- i.e., a Riemann sum for queue length
609 * integrated against time. (You can also think of the active time
610 * as a Riemann sum, for the boolean function (queue_length > 0)
611 * integrated against time, or you can think of it as the
612 * Lebesgue measure of the set on which queue_length > 0.)
613 *
614 * ^
615 * | _________
616 * 8 | i4 |
617 * | | |
618 * Queue 6 | |
619 * Length | _________ | |
620 * 4 | i2 |_______| |
621 * | | i3 |
622 * 2_______| |
623 * | i1 |
624 * |_______________________________|
625 * Time-> t1 t2 t3 t4
626 *
627 * At each change of state (entry or exit from the queue),
628 * we add the elapsed time (since the previous state change)
629 * to the active time if the queue length was non-zero during
630 * that interval; and we add the product of the elapsed time
631 * times the queue length to the running length*time sum.
632 *
633 * This method is generalizable to measuring residency
634 * in any defined system: instead of queue lengths, think
635 * of "outstanding RPC calls to server X".
636 *
637 * A large number of I/O subsystems have at least two basic
638 * "lists" of transactions they manage: one for transactions
639 * that have been accepted for processing but for which processing
640 * has yet to begin, and one for transactions which are actively
641 * being processed (but not done). For this reason, two cumulative
642 * time statistics are defined here: wait (pre-service) time,
643 * and run (service) time.
644 *
645 * All times are 64-bit nanoseconds (hrtime_t), as returned by
646 * gethrtime().
647 *
648 * The units of cumulative busy time are accumulated nanoseconds.
649 * The units of cumulative length*time products are elapsed time
650 * times queue length.
651 *
652 * Updates to the fields below are performed implicitly by calls to
653 * these five functions:
654 *
655 * kstat_waitq_enter()
656 * kstat_waitq_exit()
657 * kstat_runq_enter()
658 * kstat_runq_exit()
659 *
660 * kstat_waitq_to_runq() (see below)
661 * kstat_runq_back_to_waitq() (see below)
662 *
663 * Since kstat_waitq_exit() is typically followed immediately
664 * by kstat_runq_enter(), there is a single kstat_waitq_to_runq()
665 * function which performs both operations. This is a performance
666 * win since only one timestamp is required.
667 *
668 * In some instances, it may be necessary to move a request from
669 * the run queue back to the wait queue, e.g. for write throttling.
670 * For these situations, call kstat_runq_back_to_waitq().
671 *
672 * These fields should never be updated by any other means.
673 */
674
675 hrtime_t wtime; /* cumulative wait (pre-service) time */
676 hrtime_t wlentime; /* cumulative wait length*time product */
677 hrtime_t wlastupdate; /* last time wait queue changed */
678 hrtime_t rtime; /* cumulative run (service) time */
679 hrtime_t rlentime; /* cumulative run length*time product */
680 hrtime_t rlastupdate; /* last time run queue changed */
681
682 uint_t wcnt; /* count of elements in wait state */
683 uint_t rcnt; /* count of elements in run state */
684
685 } kstat_io_t;
686
687 #define KSTAT_IO_PTR(kptr) ((kstat_io_t *)(kptr)->ks_data)
688
689 /*
690 * Event timer statistics - cumulative elapsed time and number of events.
691 *
692 * Updates to these fields are performed implicitly by calls to
693 * kstat_timer_start() and kstat_timer_stop().
694 */
695
696 typedef struct kstat_timer {
697 char name[KSTAT_STRLEN]; /* event name */
698 uchar_t resv; /* reserved */
699 u_longlong_t num_events; /* number of events */
700 hrtime_t elapsed_time; /* cumulative elapsed time */
701 hrtime_t min_time; /* shortest event duration */
702 hrtime_t max_time; /* longest event duration */
703 hrtime_t start_time; /* previous event start time */
704 hrtime_t stop_time; /* previous event stop time */
705 } kstat_timer_t;
706
707 #define KSTAT_TIMER_PTR(kptr) ((kstat_timer_t *)(kptr)->ks_data)
708
709 #if defined(_KERNEL) || defined(_FAKE_KERNEL)
710
711 #include <sys/t_lock.h>
712
713 extern kid_t kstat_chain_id; /* bumped at each state change */
714 extern void kstat_init(void); /* initialize kstat framework */
715
716 /*
717 * Adding and deleting kstats.
718 *
719 * The typical sequence to add a kstat is:
720 *
721 * ksp = kstat_create(module, instance, name, class, type, ndata, flags);
722 * if (ksp) {
723 * ... provider initialization, if necessary
724 * kstat_install(ksp);
725 * }
726 *
727 * There are three logically distinct steps here:
728 *
729 * Step 1: System Initialization (kstat_create)
730 *
731 * kstat_create() performs system initialization. kstat_create()
732 * allocates memory for the entire kstat (header plus data), initializes
733 * all header fields, initializes the data section to all zeroes, assigns
734 * a unique KID, and puts the kstat onto the system's kstat chain.
735 * The returned kstat is marked invalid (KSTAT_FLAG_INVALID is set),
736 * because the provider (caller) has not yet had a chance to initialize
737 * the data section.
738 *
739 * By default, kstats are exported to all zones on the system. A kstat may be
740 * created via kstat_create_zone() to specify a zone to which the statistics
741 * should be exported. kstat_zone_add() may be used to specify additional
742 * zones to which the statistics are to be exported.
743 *
744 * Step 2: Provider Initialization
745 *
746 * The provider performs any necessary initialization of the data section,
747 * e.g. setting the name fields in a KSTAT_TYPE_NAMED. Virtual kstats set
748 * the ks_data field at this time. The provider may also set the ks_update,
749 * ks_snapshot, ks_private, and ks_lock fields if necessary.
750 *
751 * Step 3: Installation (kstat_install)
752 *
753 * Once the kstat is completely initialized, kstat_install() clears the
754 * INVALID flag, thus making the kstat accessible to the outside world.
755 * kstat_install() also clears the DORMANT flag for persistent kstats.
756 *
757 * Removing a kstat from the system
758 *
759 * kstat_delete(ksp) removes ksp from the kstat chain and frees all
760 * associated system resources. NOTE: When you call kstat_delete(),
761 * you must NOT be holding that kstat's ks_lock. Otherwise, you may
762 * deadlock with a kstat reader.
763 *
764 * Persistent kstats
765 *
766 * From the provider's point of view, persistence is transparent. The only
767 * difference between ephemeral (normal) kstats and persistent kstats
768 * is that you pass KSTAT_FLAG_PERSISTENT to kstat_create(). Magically,
769 * this has the effect of making your data visible even when you're
770 * not home. Persistence is important to tools like iostat, which want
771 * to get a meaningful picture of disk activity. Without persistence,
772 * raw disk i/o statistics could never accumulate: they would come and
773 * go with each open/close of the raw device.
774 *
775 * The magic of persistence works by slightly altering the behavior of
776 * kstat_create() and kstat_delete(). The first call to kstat_create()
777 * creates a new kstat, as usual. However, kstat_delete() does not
778 * actually delete the kstat: it performs one final update of the data
779 * (i.e., calls the ks_update routine), marks the kstat as dormant, and
780 * sets the ks_lock, ks_update, ks_private, and ks_snapshot fields back
781 * to their default values (since they might otherwise point to garbage,
782 * e.g. if the provider is going away). kstat clients can still access
783 * the dormant kstat just like a live kstat; they just continue to see
784 * the final data values as long as the kstat remains dormant.
785 * All subsequent kstat_create() calls simply find the already-existing,
786 * dormant kstat and return a pointer to it, without altering any fields.
787 * The provider then performs its usual initialization sequence, and
788 * calls kstat_install(). kstat_install() uses the old data values to
789 * initialize the native data (i.e., ks_update is called with KSTAT_WRITE),
790 * thus making it seem like you were never gone.
791 */
792
793 extern kstat_t *kstat_create(const char *, int, const char *, const char *,
794 uchar_t, uint_t, uchar_t);
795 extern kstat_t *kstat_create_zone(const char *, int, const char *,
796 const char *, uchar_t, uint_t, uchar_t, zoneid_t);
797 extern void kstat_install(kstat_t *);
798 extern void kstat_delete(kstat_t *);
799 extern void kstat_named_setstr(kstat_named_t *knp, const char *src);
800 extern void kstat_set_string(char *, const char *);
801 extern void kstat_delete_byname(const char *, int, const char *);
802 extern void kstat_delete_byname_zone(const char *, int, const char *, zoneid_t);
803 extern void kstat_named_init(kstat_named_t *, const char *, uchar_t);
804 extern void kstat_timer_init(kstat_timer_t *, const char *);
805 extern void kstat_waitq_enter(kstat_io_t *);
806 extern void kstat_waitq_exit(kstat_io_t *);
807 extern void kstat_runq_enter(kstat_io_t *);
808 extern void kstat_runq_exit(kstat_io_t *);
809 extern void kstat_waitq_to_runq(kstat_io_t *);
810 extern void kstat_runq_back_to_waitq(kstat_io_t *);
811 extern void kstat_timer_start(kstat_timer_t *);
812 extern void kstat_timer_stop(kstat_timer_t *);
813
814 extern void kstat_zone_add(kstat_t *, zoneid_t);
815 extern void kstat_zone_remove(kstat_t *, zoneid_t);
816 extern int kstat_zone_find(kstat_t *, zoneid_t);
817
818 extern kstat_t *kstat_hold_bykid(kid_t kid, zoneid_t);
819 extern kstat_t *kstat_hold_byname(const char *, int, const char *, zoneid_t);
820 extern void kstat_rele(kstat_t *);
821
822 #endif /* defined(_KERNEL) */
823
824 #ifdef __cplusplus
825 }
826 #endif
827
828 #endif /* _SYS_KSTAT_H */