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 https://opensource.org/licenses/CDDL-1.0. 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 26 #ifndef _SYS_KSTAT_H 27 #define _SYS_KSTAT_H 28 29 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 255 /* 254 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 snapshot */ 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 /* 96 * kstat structure and locking strategy 97 * 98 * Each kstat consists of a header section (a kstat_t) and a data section. 99 * The system maintains a set of kstats, protected by kstat_chain_lock. 100 * kstat_chain_lock protects all additions to/deletions from this set, 101 * as well as all changes to kstat headers. kstat data sections are 102 * *optionally* protected by the per-kstat ks_lock. If ks_lock is non-NULL, 103 * kstat clients (e.g. /dev/kstat) will acquire this lock for all of their 104 * operations on that kstat. It is up to the kstat provider to decide whether 105 * guaranteeing consistent data to kstat clients is sufficiently important 106 * to justify the locking cost. Note, however, that most statistic updates 107 * already occur under one of the provider's mutexes, so if the provider sets 108 * ks_lock to point to that mutex, then kstat data locking is free. 109 * 110 * NOTE: variable-size kstats MUST employ kstat data locking, to prevent 111 * data-size races with kstat clients. 112 * 113 * NOTE: ks_lock is really of type (kmutex_t *); it is declared as (void *) 114 * in the kstat header so that users don't have to be exposed to all of the 115 * kernel's lock-related data structures. 116 */ 117 118 #if defined(_KERNEL) 119 120 #define KSTAT_ENTER(k) \ 121 { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_enter(lp); } 122 123 #define KSTAT_EXIT(k) \ 124 { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_exit(lp); } 125 126 #define KSTAT_UPDATE(k, rw) (*(k)->ks_update)((k), (rw)) 127 128 #define KSTAT_SNAPSHOT(k, buf, rw) (*(k)->ks_snapshot)((k), (buf), (rw)) 129 130 #endif /* defined(_KERNEL) */ 131 132 /* 133 * kstat time 134 * 135 * All times associated with kstats (e.g. creation time, snapshot time, 136 * kstat_timer_t and kstat_io_t timestamps, etc.) are 64-bit nanosecond values, 137 * as returned by gethrtime(). The accuracy of these timestamps is machine 138 * dependent, but the precision (units) is the same across all platforms. 139 */ 140 141 /* 142 * kstat identity (KID) 143 * 144 * Each kstat is assigned a unique KID (kstat ID) when it is added to the 145 * global kstat chain. The KID is used as a cookie by /dev/kstat to 146 * request information about the corresponding kstat. There is also 147 * an identity associated with the entire kstat chain, kstat_chain_id, 148 * which is bumped each time a kstat is added or deleted. /dev/kstat uses 149 * the chain ID to detect changes in the kstat chain (e.g., a new disk 150 * coming online) between ioctl()s. 151 */ 152 153 /* 154 * kstat module, kstat instance 155 * 156 * ks_module and ks_instance contain the name and instance of the module 157 * that created the kstat. In cases where there can only be one instance, 158 * ks_instance is 0. The kernel proper (/kernel/unix) uses "unix" as its 159 * module name. 160 */ 161 162 /* 163 * kstat name 164 * 165 * ks_name gives a meaningful name to a kstat. The full kstat namespace 166 * is module.instance.name, so the name only need be unique within a 167 * module. kstat_create() will fail if you try to create a kstat with 168 * an already-used (ks_module, ks_instance, ks_name) triplet. Spaces are 169 * allowed in kstat names, but strongly discouraged, since they hinder 170 * awk-style processing at user level. 171 */ 172 173 /* 174 * kstat type 175 * 176 * The kstat mechanism provides several flavors of kstat data, defined 177 * below. The "raw" kstat type is just treated as an array of bytes; you 178 * can use this to export any kind of data you want. 179 * 180 * Some kstat types allow multiple data structures per kstat, e.g. 181 * KSTAT_TYPE_NAMED; others do not. This is part of the spec for each 182 * kstat data type. 183 * 184 * User-level tools should *not* rely on the #define KSTAT_NUM_TYPES. To 185 * get this information, read out the standard system kstat "kstat_types". 186 */ 187 188 #define KSTAT_TYPE_RAW 0 /* can be anything */ 189 /* ks_ndata >= 1 */ 190 #define KSTAT_TYPE_NAMED 1 /* name/value pair */ 191 /* ks_ndata >= 1 */ 192 #define KSTAT_TYPE_INTR 2 /* interrupt statistics */ 193 /* ks_ndata == 1 */ 194 #define KSTAT_TYPE_IO 3 /* I/O statistics */ 195 /* ks_ndata == 1 */ 196 #define KSTAT_TYPE_TIMER 4 /* event timer */ 197 /* ks_ndata >= 1 */ 198 199 #define KSTAT_NUM_TYPES 5 200 201 /* 202 * kstat class 203 * 204 * Each kstat can be characterized as belonging to some broad class 205 * of statistics, e.g. disk, tape, net, vm, streams, etc. This field 206 * can be used as a filter to extract related kstats. The following 207 * values are currently in use: disk, tape, net, controller, vm, kvm, 208 * hat, streams, kstat, and misc. (The kstat class encompasses things 209 * like kstat_types.) 210 */ 211 212 /* 213 * kstat flags 214 * 215 * Any of the following flags may be passed to kstat_create(). They are 216 * all zero by default. 217 * 218 * KSTAT_FLAG_VIRTUAL: 219 * 220 * Tells kstat_create() not to allocate memory for the 221 * kstat data section; instead, you will set the ks_data 222 * field to point to the data you wish to export. This 223 * provides a convenient way to export existing data 224 * structures. 225 * 226 * KSTAT_FLAG_VAR_SIZE: 227 * 228 * The size of the kstat you are creating will vary over time. 229 * For example, you may want to use the kstat mechanism to 230 * export a linked list. NOTE: The kstat framework does not 231 * manage the data section, so all variable-size kstats must be 232 * virtual kstats. Moreover, variable-size kstats MUST employ 233 * kstat data locking to prevent data-size races with kstat 234 * clients. See the section on "kstat snapshot" for details. 235 * 236 * KSTAT_FLAG_WRITABLE: 237 * 238 * Makes the kstat's data section writable by root. 239 * The ks_snapshot routine (see below) does not need to check for 240 * this; permission checking is handled in the kstat driver. 241 * 242 * KSTAT_FLAG_PERSISTENT: 243 * 244 * Indicates that this kstat is to be persistent over time. 245 * For persistent kstats, kstat_delete() simply marks the 246 * kstat as dormant; a subsequent kstat_create() reactivates 247 * the kstat. This feature is provided so that statistics 248 * are not lost across driver close/open (e.g., raw disk I/O 249 * on a disk with no mounted partitions.) 250 * NOTE: Persistent kstats cannot be virtual, since ks_data 251 * points to garbage as soon as the driver goes away. 252 * 253 * The following flags are maintained by the kstat framework: 254 * 255 * KSTAT_FLAG_DORMANT: 256 * 257 * For persistent kstats, indicates that the kstat is in the 258 * dormant state (e.g., the corresponding device is closed). 259 * 260 * KSTAT_FLAG_INVALID: 261 * 262 * This flag is set when a kstat is in a transitional state, 263 * e.g. between kstat_create() and kstat_install(). 264 * kstat clients must not attempt to access the kstat's data 265 * if this flag is set. 266 */ 267 268 #define KSTAT_FLAG_VIRTUAL 0x01 269 #define KSTAT_FLAG_VAR_SIZE 0x02 270 #define KSTAT_FLAG_WRITABLE 0x04 271 #define KSTAT_FLAG_PERSISTENT 0x08 272 #define KSTAT_FLAG_DORMANT 0x10 273 #define KSTAT_FLAG_INVALID 0x20 274 #define KSTAT_FLAG_LONGSTRINGS 0x40 275 #define KSTAT_FLAG_NO_HEADERS 0x80 276 277 /* 278 * Dynamic update support 279 * 280 * The kstat mechanism allows for an optional ks_update function to update 281 * kstat data. This is useful for drivers where the underlying device 282 * keeps cheap hardware stats, but extraction is expensive. Instead of 283 * constantly keeping the kstat data section up to date, you can supply a 284 * ks_update function which updates the kstat's data section on demand. 285 * To take advantage of this feature, simply set the ks_update field before 286 * calling kstat_install(). 287 * 288 * The ks_update function, if supplied, must have the following structure: 289 * 290 * int 291 * foo_kstat_update(kstat_t *ksp, int rw) 292 * { 293 * if (rw == KSTAT_WRITE) { 294 * ... update the native stats from ksp->ks_data; 295 * return EACCES if you don't support this 296 * } else { 297 * ... update ksp->ks_data from the native stats 298 * } 299 * } 300 * 301 * The ks_update return codes are: 0 for success, EACCES if you don't allow 302 * KSTAT_WRITE, and EIO for any other type of error. 303 * 304 * In general, the ks_update function may need to refer to provider-private 305 * data; for example, it may need a pointer to the provider's raw statistics. 306 * The ks_private field is available for this purpose. Its use is entirely 307 * at the provider's discretion. 308 * 309 * All variable-size kstats MUST supply a ks_update routine, which computes 310 * and sets ks_data_size (and ks_ndata if that is meaningful), since these 311 * are needed to perform kstat snapshots (see below). 312 * 313 * No kstat locking should be done inside the ks_update routine. The caller 314 * will already be holding the kstat's ks_lock (to ensure consistent data). 315 */ 316 317 #define KSTAT_READ 0 318 #define KSTAT_WRITE 1 319 320 /* 321 * Kstat snapshot 322 * 323 * In order to get a consistent view of a kstat's data, clients must obey 324 * the kstat's locking strategy. However, these clients may need to perform 325 * operations on the data which could cause a fault (e.g. copyout()), or 326 * operations which are simply expensive. Doing so could cause deadlock 327 * (e.g. if you're holding a disk's kstat lock which is ultimately required 328 * to resolve a copyout() fault), performance degradation (since the providers' 329 * activity is serialized at the kstat lock), device timing problems, etc. 330 * 331 * To avoid these problems, kstat data is provided via snapshots. Taking 332 * a snapshot is a simple process: allocate a wired-down kernel buffer, 333 * acquire the kstat's data lock, copy the data into the buffer ("take the 334 * snapshot"), and release the lock. This ensures that the kstat's data lock 335 * will be held as briefly as possible, and that no faults will occur while 336 * the lock is held. 337 * 338 * Normally, the snapshot is taken by default_kstat_snapshot(), which 339 * timestamps the data (sets ks_snaptime), copies it, and does a little 340 * massaging to deal with incomplete transactions on i/o kstats. However, 341 * this routine only works for kstats with contiguous data (the typical case). 342 * If you create a kstat whose data is, say, a linked list, you must provide 343 * your own ks_snapshot routine. The routine you supply must have the 344 * following prototype (replace "foo" with something appropriate): 345 * 346 * int foo_kstat_snapshot(kstat_t *ksp, void *buf, int rw); 347 * 348 * The minimal snapshot routine -- one which copies contiguous data that 349 * doesn't need any massaging -- would be this: 350 * 351 * ksp->ks_snaptime = gethrtime(); 352 * if (rw == KSTAT_WRITE) 353 * memcpy(ksp->ks_data, buf, ksp->ks_data_size); 354 * else 355 * memcpy(buf, ksp->ks_data, ksp->ks_data_size); 356 * return (0); 357 * 358 * A more illuminating example is taking a snapshot of a linked list: 359 * 360 * ksp->ks_snaptime = gethrtime(); 361 * if (rw == KSTAT_WRITE) 362 * return (EACCES); ... See below ... 363 * for (foo = first_foo; foo; foo = foo->next) { 364 * memcpy(buf, foo, sizeof (struct foo)); 365 * buf = ((struct foo *) buf) + 1; 366 * } 367 * return (0); 368 * 369 * In the example above, we have decided that we don't want to allow 370 * KSTAT_WRITE access, so we return EACCES if this is attempted. 371 * 372 * The key points are: 373 * 374 * (1) ks_snaptime must be set (via gethrtime()) to timestamp the data. 375 * (2) Data gets copied from the kstat to the buffer on KSTAT_READ, 376 * and from the buffer to the kstat on KSTAT_WRITE. 377 * (3) ks_snapshot return values are: 0 for success, EACCES if you 378 * don't allow KSTAT_WRITE, and EIO for any other type of error. 379 * 380 * Named kstats (see section on "Named statistics" below) containing long 381 * strings (KSTAT_DATA_STRING) need special handling. The kstat driver 382 * assumes that all strings are copied into the buffer after the array of 383 * named kstats, and the pointers (KSTAT_NAMED_STR_PTR()) are updated to point 384 * into the copy within the buffer. The default snapshot routine does this, 385 * but overriding routines should contain at least the following: 386 * 387 * if (rw == KSTAT_READ) { 388 * kstat_named_t *knp = buf; 389 * char *end = knp + ksp->ks_ndata; 390 * uint_t i; 391 * 392 * ... Do the regular copy ... 393 * memcpy(buf, ksp->ks_data, sizeof (kstat_named_t) * ksp->ks_ndata); 394 * 395 * for (i = 0; i < ksp->ks_ndata; i++, knp++) { 396 * if (knp[i].data_type == KSTAT_DATA_STRING && 397 * KSTAT_NAMED_STR_PTR(knp) != NULL) { 398 * memcpy(end, KSTAT_NAMED_STR_PTR(knp), 399 * KSTAT_NAMED_STR_BUFLEN(knp)); 400 * KSTAT_NAMED_STR_PTR(knp) = end; 401 * end += KSTAT_NAMED_STR_BUFLEN(knp); 402 * } 403 * } 404 */ 405 406 /* 407 * Named statistics. 408 * 409 * List of arbitrary name=value statistics. 410 */ 411 412 typedef struct kstat_named { 413 char name[KSTAT_STRLEN]; /* name of counter */ 414 uchar_t data_type; /* data type */ 415 union { 416 char c[16]; /* enough for 128-bit ints */ 417 int32_t i32; 418 uint32_t ui32; 419 struct { 420 union { 421 char *ptr; /* NULL-term string */ 422 #if defined(_KERNEL) && defined(_MULTI_DATAMODEL) 423 caddr32_t ptr32; 424 #endif 425 char __pad[8]; /* 64-bit padding */ 426 } addr; 427 uint32_t len; /* # bytes for strlen + '\0' */ 428 } str; 429 /* 430 * The int64_t and uint64_t types are not valid for a maximally conformant 431 * 32-bit compilation environment (cc -Xc) using compilers prior to the 432 * introduction of C99 conforming compiler (reference ISO/IEC 9899:1990). 433 * In these cases, the visibility of i64 and ui64 is only permitted for 434 * 64-bit compilation environments or 32-bit non-maximally conformant 435 * C89 or C90 ANSI C compilation environments (cc -Xt and cc -Xa). In the 436 * C99 ANSI C compilation environment, the long long type is supported. 437 * The _INT64_TYPE is defined by the implementation (see sys/inttypes.h). 438 */ 439 #if defined(_INT64_TYPE) 440 int64_t i64; 441 uint64_t ui64; 442 #endif 443 long l; 444 ulong_t ul; 445 446 /* These structure members are obsolete */ 447 448 longlong_t ll; 449 u_longlong_t ull; 450 float f; 451 double d; 452 } value; /* value of counter */ 453 } kstat_named_t; 454 455 #define KSTAT_DATA_CHAR 0 456 #define KSTAT_DATA_INT32 1 457 #define KSTAT_DATA_UINT32 2 458 #define KSTAT_DATA_INT64 3 459 #define KSTAT_DATA_UINT64 4 460 461 #if !defined(_LP64) 462 #define KSTAT_DATA_LONG KSTAT_DATA_INT32 463 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT32 464 #else 465 #if !defined(_KERNEL) 466 #define KSTAT_DATA_LONG KSTAT_DATA_INT64 467 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT64 468 #else 469 #define KSTAT_DATA_LONG 7 /* only visible to the kernel */ 470 #define KSTAT_DATA_ULONG 8 /* only visible to the kernel */ 471 #endif /* !_KERNEL */ 472 #endif /* !_LP64 */ 473 474 /* 475 * Statistics exporting named kstats with long strings (KSTAT_DATA_STRING) 476 * may not make the assumption that ks_data_size is equal to (ks_ndata * sizeof 477 * (kstat_named_t)). ks_data_size in these cases is equal to the sum of the 478 * amount of space required to store the strings (ie, the sum of 479 * KSTAT_NAMED_STR_BUFLEN() for all KSTAT_DATA_STRING statistics) plus the 480 * space required to store the kstat_named_t's. 481 * 482 * The default update routine will update ks_data_size automatically for 483 * variable-length kstats containing long strings (using the default update 484 * routine only makes sense if the string is the only thing that is changing 485 * in size, and ks_ndata is constant). Fixed-length kstats containing long 486 * strings must explicitly change ks_data_size (after creation but before 487 * initialization) to reflect the correct amount of space required for the 488 * long strings and the kstat_named_t's. 489 */ 490 #define KSTAT_DATA_STRING 9 491 492 /* These types are obsolete */ 493 494 #define KSTAT_DATA_LONGLONG KSTAT_DATA_INT64 495 #define KSTAT_DATA_ULONGLONG KSTAT_DATA_UINT64 496 #define KSTAT_DATA_FLOAT 5 497 #define KSTAT_DATA_DOUBLE 6 498 499 #define KSTAT_NAMED_PTR(kptr) ((kstat_named_t *)(kptr)->ks_data) 500 501 /* 502 * Retrieve the pointer of the string contained in the given named kstat. 503 */ 504 #define KSTAT_NAMED_STR_PTR(knptr) ((knptr)->value.str.addr.ptr) 505 506 /* 507 * Retrieve the length of the buffer required to store the string in the given 508 * named kstat. 509 */ 510 #define KSTAT_NAMED_STR_BUFLEN(knptr) ((knptr)->value.str.len) 511 512 /* 513 * Interrupt statistics. 514 * 515 * An interrupt is a hard interrupt (sourced from the hardware device 516 * itself), a soft interrupt (induced by the system via the use of 517 * some system interrupt source), a watchdog interrupt (induced by 518 * a periodic timer call), spurious (an interrupt entry point was 519 * entered but there was no interrupt condition to service), 520 * or multiple service (an interrupt condition was detected and 521 * serviced just prior to returning from any of the other types). 522 * 523 * Measurement of the spurious class of interrupts is useful for 524 * autovectored devices in order to pinpoint any interrupt latency 525 * problems in a particular system configuration. 526 * 527 * Devices that have more than one interrupt of the same 528 * type should use multiple structures. 529 */ 530 531 #define KSTAT_INTR_HARD 0 532 #define KSTAT_INTR_SOFT 1 533 #define KSTAT_INTR_WATCHDOG 2 534 #define KSTAT_INTR_SPURIOUS 3 535 #define KSTAT_INTR_MULTSVC 4 536 537 #define KSTAT_NUM_INTRS 5 538 539 typedef struct kstat_intr { 540 uint_t intrs[KSTAT_NUM_INTRS]; /* interrupt counters */ 541 } kstat_intr_t; 542 543 #define KSTAT_INTR_PTR(kptr) ((kstat_intr_t *)(kptr)->ks_data) 544 545 /* 546 * I/O statistics. 547 */ 548 549 typedef struct kstat_io { 550 551 /* 552 * Basic counters. 553 * 554 * The counters should be updated at the end of service 555 * (e.g., just prior to calling biodone()). 556 */ 557 558 u_longlong_t nread; /* number of bytes read */ 559 u_longlong_t nwritten; /* number of bytes written */ 560 uint_t reads; /* number of read operations */ 561 uint_t writes; /* number of write operations */ 562 563 /* 564 * Accumulated time and queue length statistics. 565 * 566 * Accumulated time statistics are kept as a running sum 567 * of "active" time. Queue length statistics are kept as a 568 * running sum of the product of queue length and elapsed time 569 * at that length -- i.e., a Riemann sum for queue length 570 * integrated against time. (You can also think of the active time 571 * as a Riemann sum, for the boolean function (queue_length > 0) 572 * integrated against time, or you can think of it as the 573 * Lebesgue measure of the set on which queue_length > 0.) 574 * 575 * ^ 576 * | _________ 577 * 8 | i4 | 578 * | | | 579 * Queue 6 | | 580 * Length | _________ | | 581 * 4 | i2 |_______| | 582 * | | i3 | 583 * 2_______| | 584 * | i1 | 585 * |_______________________________| 586 * Time-> t1 t2 t3 t4 587 * 588 * At each change of state (entry or exit from the queue), 589 * we add the elapsed time (since the previous state change) 590 * to the active time if the queue length was non-zero during 591 * that interval; and we add the product of the elapsed time 592 * times the queue length to the running length*time sum. 593 * 594 * This method is generalizable to measuring residency 595 * in any defined system: instead of queue lengths, think 596 * of "outstanding RPC calls to server X". 597 * 598 * A large number of I/O subsystems have at least two basic 599 * "lists" of transactions they manage: one for transactions 600 * that have been accepted for processing but for which processing 601 * has yet to begin, and one for transactions which are actively 602 * being processed (but not done). For this reason, two cumulative 603 * time statistics are defined here: wait (pre-service) time, 604 * and run (service) time. 605 * 606 * All times are 64-bit nanoseconds (hrtime_t), as returned by 607 * gethrtime(). 608 * 609 * The units of cumulative busy time are accumulated nanoseconds. 610 * The units of cumulative length*time products are elapsed time 611 * times queue length. 612 * 613 * Updates to the fields below are performed implicitly by calls to 614 * these five functions: 615 * 616 * kstat_waitq_enter() 617 * kstat_waitq_exit() 618 * kstat_runq_enter() 619 * kstat_runq_exit() 620 * 621 * kstat_waitq_to_runq() (see below) 622 * kstat_runq_back_to_waitq() (see below) 623 * 624 * Since kstat_waitq_exit() is typically followed immediately 625 * by kstat_runq_enter(), there is a single kstat_waitq_to_runq() 626 * function which performs both operations. This is a performance 627 * win since only one timestamp is required. 628 * 629 * In some instances, it may be necessary to move a request from 630 * the run queue back to the wait queue, e.g. for write throttling. 631 * For these situations, call kstat_runq_back_to_waitq(). 632 * 633 * These fields should never be updated by any other means. 634 */ 635 636 hrtime_t wtime; /* cumulative wait (pre-service) time */ 637 hrtime_t wlentime; /* cumulative wait length*time product */ 638 hrtime_t wlastupdate; /* last time wait queue changed */ 639 hrtime_t rtime; /* cumulative run (service) time */ 640 hrtime_t rlentime; /* cumulative run length*time product */ 641 hrtime_t rlastupdate; /* last time run queue changed */ 642 643 uint_t wcnt; /* count of elements in wait state */ 644 uint_t rcnt; /* count of elements in run state */ 645 646 } kstat_io_t; 647 648 #define KSTAT_IO_PTR(kptr) ((kstat_io_t *)(kptr)->ks_data) 649 650 /* 651 * Event timer statistics - cumulative elapsed time and number of events. 652 * 653 * Updates to these fields are performed implicitly by calls to 654 * kstat_timer_start() and kstat_timer_stop(). 655 */ 656 657 typedef struct kstat_timer { 658 char name[KSTAT_STRLEN]; /* event name */ 659 uchar_t resv; /* reserved */ 660 u_longlong_t num_events; /* number of events */ 661 hrtime_t elapsed_time; /* cumulative elapsed time */ 662 hrtime_t min_time; /* shortest event duration */ 663 hrtime_t max_time; /* longest event duration */ 664 hrtime_t start_time; /* previous event start time */ 665 hrtime_t stop_time; /* previous event stop time */ 666 } kstat_timer_t; 667 668 #define KSTAT_TIMER_PTR(kptr) ((kstat_timer_t *)(kptr)->ks_data) 669 670 #if defined(_KERNEL) 671 672 #include <sys/t_lock.h> 673 674 extern kid_t kstat_chain_id; /* bumped at each state change */ 675 extern void kstat_init(void); /* initialize kstat framework */ 676 677 /* 678 * Adding and deleting kstats. 679 * 680 * The typical sequence to add a kstat is: 681 * 682 * ksp = kstat_create(module, instance, name, class, type, ndata, flags); 683 * if (ksp) { 684 * ... provider initialization, if necessary 685 * kstat_install(ksp); 686 * } 687 * 688 * There are three logically distinct steps here: 689 * 690 * Step 1: System Initialization (kstat_create) 691 * 692 * kstat_create() performs system initialization. kstat_create() 693 * allocates memory for the entire kstat (header plus data), initializes 694 * all header fields, initializes the data section to all zeroes, assigns 695 * a unique KID, and puts the kstat onto the system's kstat chain. 696 * The returned kstat is marked invalid (KSTAT_FLAG_INVALID is set), 697 * because the provider (caller) has not yet had a chance to initialize 698 * the data section. 699 * 700 * By default, kstats are exported to all zones on the system. A kstat may be 701 * created via kstat_create_zone() to specify a zone to which the statistics 702 * should be exported. kstat_zone_add() may be used to specify additional 703 * zones to which the statistics are to be exported. 704 * 705 * Step 2: Provider Initialization 706 * 707 * The provider performs any necessary initialization of the data section, 708 * e.g. setting the name fields in a KSTAT_TYPE_NAMED. Virtual kstats set 709 * the ks_data field at this time. The provider may also set the ks_update, 710 * ks_snapshot, ks_private, and ks_lock fields if necessary. 711 * 712 * Step 3: Installation (kstat_install) 713 * 714 * Once the kstat is completely initialized, kstat_install() clears the 715 * INVALID flag, thus making the kstat accessible to the outside world. 716 * kstat_install() also clears the DORMANT flag for persistent kstats. 717 * 718 * Removing a kstat from the system 719 * 720 * kstat_delete(ksp) removes ksp from the kstat chain and frees all 721 * associated system resources. NOTE: When you call kstat_delete(), 722 * you must NOT be holding that kstat's ks_lock. Otherwise, you may 723 * deadlock with a kstat reader. 724 * 725 * Persistent kstats 726 * 727 * From the provider's point of view, persistence is transparent. The only 728 * difference between ephemeral (normal) kstats and persistent kstats 729 * is that you pass KSTAT_FLAG_PERSISTENT to kstat_create(). Magically, 730 * this has the effect of making your data visible even when you're 731 * not home. Persistence is important to tools like iostat, which want 732 * to get a meaningful picture of disk activity. Without persistence, 733 * raw disk i/o statistics could never accumulate: they would come and 734 * go with each open/close of the raw device. 735 * 736 * The magic of persistence works by slightly altering the behavior of 737 * kstat_create() and kstat_delete(). The first call to kstat_create() 738 * creates a new kstat, as usual. However, kstat_delete() does not 739 * actually delete the kstat: it performs one final update of the data 740 * (i.e., calls the ks_update routine), marks the kstat as dormant, and 741 * sets the ks_lock, ks_update, ks_private, and ks_snapshot fields back 742 * to their default values (since they might otherwise point to garbage, 743 * e.g. if the provider is going away). kstat clients can still access 744 * the dormant kstat just like a live kstat; they just continue to see 745 * the final data values as long as the kstat remains dormant. 746 * All subsequent kstat_create() calls simply find the already-existing, 747 * dormant kstat and return a pointer to it, without altering any fields. 748 * The provider then performs its usual initialization sequence, and 749 * calls kstat_install(). kstat_install() uses the old data values to 750 * initialize the native data (i.e., ks_update is called with KSTAT_WRITE), 751 * thus making it seem like you were never gone. 752 */ 753 754 extern kstat_t *kstat_create(const char *, int, const char *, const char *, 755 uchar_t, uint_t, uchar_t); 756 extern kstat_t *kstat_create_zone(const char *, int, const char *, 757 const char *, uchar_t, uint_t, uchar_t, zoneid_t); 758 extern void kstat_install(kstat_t *); 759 extern void kstat_delete(kstat_t *); 760 extern void kstat_named_setstr(kstat_named_t *knp, const char *src); 761 extern void kstat_set_string(char *, const char *); 762 extern void kstat_delete_byname(const char *, int, const char *); 763 extern void kstat_delete_byname_zone(const char *, int, const char *, zoneid_t); 764 extern void kstat_named_init(kstat_named_t *, const char *, uchar_t); 765 extern void kstat_timer_init(kstat_timer_t *, const char *); 766 extern void kstat_timer_start(kstat_timer_t *); 767 extern void kstat_timer_stop(kstat_timer_t *); 768 769 extern void kstat_zone_add(kstat_t *, zoneid_t); 770 extern void kstat_zone_remove(kstat_t *, zoneid_t); 771 extern int kstat_zone_find(kstat_t *, zoneid_t); 772 773 extern kstat_t *kstat_hold_bykid(kid_t kid, zoneid_t); 774 extern kstat_t *kstat_hold_byname(const char *, int, const char *, zoneid_t); 775 extern void kstat_rele(kstat_t *); 776 777 #endif /* defined(_KERNEL) */ 778 779 #ifdef __cplusplus 780 } 781 #endif 782 783 #endif /* _SYS_KSTAT_H */ 784