2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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. Neither the name of the author nor the names of any co-contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * This module holds the global variables and functions used to maintain
32 * lock_object structures.
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
39 #include "opt_mprof.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
45 #include <sys/linker_set.h>
47 #include <sys/lock_profile.h>
48 #include <sys/malloc.h>
53 #include <sys/sysctl.h>
59 #include <machine/cpufunc.h>
61 CTASSERT(LOCK_CLASS_MAX == 15);
63 struct lock_class *lock_classes[LOCK_CLASS_MAX + 1] = {
65 &lock_class_mtx_sleep,
73 lock_init(struct lock_object *lock, struct lock_class *class, const char *name,
74 const char *type, int flags)
78 /* Check for double-init and zero object. */
79 KASSERT(!lock_initalized(lock), ("lock \"%s\" %p already initialized",
82 /* Look up lock class to find its index. */
83 for (i = 0; i < LOCK_CLASS_MAX; i++)
84 if (lock_classes[i] == class) {
85 lock->lo_flags = i << LO_CLASSSHIFT;
88 KASSERT(i < LOCK_CLASS_MAX, ("unknown lock class %p", class));
90 /* Initialize the lock object. */
92 lock->lo_flags |= flags | LO_INITIALIZED;
93 LOCK_LOG_INIT(lock, 0);
94 WITNESS_INIT(lock, (type != NULL) ? type : name);
98 lock_destroy(struct lock_object *lock)
101 KASSERT(lock_initalized(lock), ("lock %p is not initialized", lock));
102 WITNESS_DESTROY(lock);
103 LOCK_LOG_DESTROY(lock, 0);
104 lock->lo_flags &= ~LO_INITIALIZED;
108 DB_SHOW_COMMAND(lock, db_show_lock)
110 struct lock_object *lock;
111 struct lock_class *class;
115 lock = (struct lock_object *)addr;
116 if (LO_CLASSINDEX(lock) > LOCK_CLASS_MAX) {
117 db_printf("Unknown lock class: %d\n", LO_CLASSINDEX(lock));
120 class = LOCK_CLASS(lock);
121 db_printf(" class: %s\n", class->lc_name);
122 db_printf(" name: %s\n", lock->lo_name);
123 class->lc_ddb_show(lock);
127 #ifdef LOCK_PROFILING
130 * One object per-thread for each lock the thread owns. Tracks individual
133 struct lock_profile_object {
134 LIST_ENTRY(lock_profile_object) lpo_link;
135 struct lock_object *lpo_obj;
136 const char *lpo_file;
140 u_int64_t lpo_acqtime;
141 u_int64_t lpo_waittime;
142 u_int lpo_contest_locking;
146 * One lock_prof for each (file, line, lock object) triple.
149 SLIST_ENTRY(lock_prof) link;
150 struct lock_class *class;
155 uintmax_t cnt_wait_max;
160 uintmax_t cnt_contest_locking;
163 SLIST_HEAD(lphead, lock_prof);
165 #define LPROF_HASH_SIZE 4096
166 #define LPROF_HASH_MASK (LPROF_HASH_SIZE - 1)
167 #define LPROF_CACHE_SIZE 4096
170 * Array of objects and profs for each type of object for each cpu. Spinlocks
171 * are handled seperately because a thread may be preempted and acquire a
172 * spinlock while in the lock profiling code of a non-spinlock. In this way
173 * we only need a critical section to protect the per-cpu lists.
175 struct lock_prof_type {
176 struct lphead lpt_lpalloc;
177 struct lpohead lpt_lpoalloc;
178 struct lphead lpt_hash[LPROF_HASH_SIZE];
179 struct lock_prof lpt_prof[LPROF_CACHE_SIZE];
180 struct lock_profile_object lpt_objs[LPROF_CACHE_SIZE];
183 struct lock_prof_cpu {
184 struct lock_prof_type lpc_types[2]; /* One for spin one for other. */
187 struct lock_prof_cpu *lp_cpu[MAXCPU];
189 int lock_prof_enable = 0;
191 /* SWAG: sbuf size = avg stat. line size * number of locks */
192 #define LPROF_SBUF_SIZE 256 * 400
194 static int lock_prof_rejected;
195 static int lock_prof_skipspin;
196 static int lock_prof_skipcount;
198 #ifndef USE_CPU_NANOSECONDS
206 /* From bintime2timespec */
207 ns = bt.sec * (u_int64_t)1000000000;
208 ns += ((uint64_t)1000000000 * (uint32_t)(bt.frac >> 32)) >> 32;
214 lock_prof_init_type(struct lock_prof_type *type)
218 SLIST_INIT(&type->lpt_lpalloc);
219 LIST_INIT(&type->lpt_lpoalloc);
220 for (i = 0; i < LPROF_CACHE_SIZE; i++) {
221 SLIST_INSERT_HEAD(&type->lpt_lpalloc, &type->lpt_prof[i],
223 LIST_INSERT_HEAD(&type->lpt_lpoalloc, &type->lpt_objs[i],
229 lock_prof_init(void *arg)
233 for (cpu = 0; cpu <= mp_maxid; cpu++) {
234 lp_cpu[cpu] = malloc(sizeof(*lp_cpu[cpu]), M_DEVBUF,
236 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[0]);
237 lock_prof_init_type(&lp_cpu[cpu]->lpc_types[1]);
240 SYSINIT(lockprof, SI_SUB_SMP, SI_ORDER_ANY, lock_prof_init, NULL);
243 lock_prof_reset(void)
245 struct lock_prof_cpu *lpc;
248 enabled = lock_prof_enable;
249 lock_prof_enable = 0;
250 pause("lpreset", hz / 10);
251 for (cpu = 0; cpu <= mp_maxid; cpu++) {
253 for (i = 0; i < LPROF_CACHE_SIZE; i++) {
254 LIST_REMOVE(&lpc->lpc_types[0].lpt_objs[i], lpo_link);
255 LIST_REMOVE(&lpc->lpc_types[1].lpt_objs[i], lpo_link);
257 bzero(lpc, sizeof(*lpc));
258 lock_prof_init_type(&lpc->lpc_types[0]);
259 lock_prof_init_type(&lpc->lpc_types[1]);
261 lock_prof_enable = enabled;
265 lock_prof_output(struct lock_prof *lp, struct sbuf *sb)
269 for (p = lp->file; p != NULL && strncmp(p, "../", 3) == 0; p += 3);
271 "%8ju %9ju %11ju %11ju %11ju %6ju %6ju %2ju %6ju %s:%d (%s:%s)\n",
272 lp->cnt_max / 1000, lp->cnt_wait_max / 1000, lp->cnt_tot / 1000,
273 lp->cnt_wait / 1000, lp->cnt_cur,
274 lp->cnt_cur == 0 ? (uintmax_t)0 :
275 lp->cnt_tot / (lp->cnt_cur * 1000),
276 lp->cnt_cur == 0 ? (uintmax_t)0 :
277 lp->cnt_wait / (lp->cnt_cur * 1000),
278 (uintmax_t)0, lp->cnt_contest_locking,
279 p, lp->line, lp->class->lc_name, lp->name);
283 lock_prof_sum(struct lock_prof *match, struct lock_prof *dst, int hash,
286 struct lock_prof_type *type;
290 dst->file = match->file;
291 dst->line = match->line;
292 dst->class = match->class;
293 dst->name = match->name;
295 for (cpu = 0; cpu <= mp_maxid; cpu++) {
296 if (lp_cpu[cpu] == NULL)
298 type = &lp_cpu[cpu]->lpc_types[spin];
299 SLIST_FOREACH(l, &type->lpt_hash[hash], link) {
302 if (l->file != match->file || l->line != match->line ||
303 l->name != match->name)
306 if (l->cnt_max > dst->cnt_max)
307 dst->cnt_max = l->cnt_max;
308 if (l->cnt_wait_max > dst->cnt_wait_max)
309 dst->cnt_wait_max = l->cnt_wait_max;
310 dst->cnt_tot += l->cnt_tot;
311 dst->cnt_wait += l->cnt_wait;
312 dst->cnt_cur += l->cnt_cur;
313 dst->cnt_contest_locking += l->cnt_contest_locking;
320 lock_prof_type_stats(struct lock_prof_type *type, struct sbuf *sb, int spin,
326 for (i = 0; i < LPROF_HASH_SIZE; ++i) {
327 SLIST_FOREACH(l, &type->lpt_hash[i], link) {
328 struct lock_prof lp = {};
332 lock_prof_sum(l, &lp, i, spin, t);
333 lock_prof_output(&lp, sb);
334 if (sbuf_overflowed(sb))
341 dump_lock_prof_stats(SYSCTL_HANDLER_ARGS)
343 static int multiplier = 1;
349 sb = sbuf_new(NULL, NULL, LPROF_SBUF_SIZE * multiplier, SBUF_FIXEDLEN);
350 sbuf_printf(sb, "\n%8s %9s %11s %11s %11s %6s %6s %2s %6s %s\n",
351 "max", "wait_max", "total", "wait_total", "count", "avg", "wait_avg", "cnt_hold", "cnt_lock", "name");
352 enabled = lock_prof_enable;
353 lock_prof_enable = 0;
354 pause("lpreset", hz / 10);
356 for (cpu = 0; cpu <= mp_maxid; cpu++) {
357 if (lp_cpu[cpu] == NULL)
359 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[0], sb, 0, t);
360 lock_prof_type_stats(&lp_cpu[cpu]->lpc_types[1], sb, 1, t);
361 if (sbuf_overflowed(sb)) {
367 lock_prof_enable = enabled;
370 error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
376 enable_lock_prof(SYSCTL_HANDLER_ARGS)
380 v = lock_prof_enable;
381 error = sysctl_handle_int(oidp, &v, v, req);
384 if (req->newptr == NULL)
386 if (v == lock_prof_enable)
390 lock_prof_enable = !!v;
396 reset_lock_prof_stats(SYSCTL_HANDLER_ARGS)
401 error = sysctl_handle_int(oidp, &v, 0, req);
404 if (req->newptr == NULL)
413 static struct lock_prof *
414 lock_profile_lookup(struct lock_object *lo, int spin, const char *file,
417 const char *unknown = "(unknown)";
418 struct lock_prof_type *type;
419 struct lock_prof *lp;
425 if (p == NULL || *p == '\0')
427 hash = (uintptr_t)lo->lo_name * 31 + (uintptr_t)p * 31 + line;
428 hash &= LPROF_HASH_MASK;
429 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
430 head = &type->lpt_hash[hash];
431 SLIST_FOREACH(lp, head, link) {
432 if (lp->line == line && lp->file == p &&
433 lp->name == lo->lo_name)
437 lp = SLIST_FIRST(&type->lpt_lpalloc);
439 lock_prof_rejected++;
442 SLIST_REMOVE_HEAD(&type->lpt_lpalloc, link);
445 lp->class = LOCK_CLASS(lo);
446 lp->name = lo->lo_name;
447 SLIST_INSERT_HEAD(&type->lpt_hash[hash], lp, link);
451 static struct lock_profile_object *
452 lock_profile_object_lookup(struct lock_object *lo, int spin, const char *file,
455 struct lock_profile_object *l;
456 struct lock_prof_type *type;
457 struct lpohead *head;
459 head = &curthread->td_lprof[spin];
460 LIST_FOREACH(l, head, lpo_link)
461 if (l->lpo_obj == lo && l->lpo_file == file &&
465 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
466 l = LIST_FIRST(&type->lpt_lpoalloc);
468 lock_prof_rejected++;
472 LIST_REMOVE(l, lpo_link);
478 LIST_INSERT_HEAD(head, l, lpo_link);
484 lock_profile_obtain_lock_success(struct lock_object *lo, int contested,
485 uint64_t waittime, const char *file, int line)
487 static int lock_prof_count;
488 struct lock_profile_object *l;
491 /* don't reset the timer when/if recursing */
492 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE))
494 if (lock_prof_skipcount &&
495 (++lock_prof_count % lock_prof_skipcount) != 0)
497 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
498 if (spin && lock_prof_skipspin == 1)
500 l = lock_profile_object_lookup(lo, spin, file, line);
504 if (++l->lpo_ref > 1)
506 l->lpo_contest_locking = contested;
507 l->lpo_acqtime = nanoseconds();
508 if (waittime && (l->lpo_acqtime > waittime))
509 l->lpo_waittime = l->lpo_acqtime - waittime;
515 lock_profile_release_lock(struct lock_object *lo)
517 struct lock_profile_object *l;
518 struct lock_prof_type *type;
519 struct lock_prof *lp;
521 struct lpohead *head;
524 if (!lock_prof_enable || (lo->lo_flags & LO_NOPROFILE))
526 spin = (LOCK_CLASS(lo)->lc_flags & LC_SPINLOCK) ? 1 : 0;
527 head = &curthread->td_lprof[spin];
529 LIST_FOREACH(l, head, lpo_link)
530 if (l->lpo_obj == lo)
534 if (--l->lpo_ref > 0)
536 lp = lock_profile_lookup(lo, spin, l->lpo_file, l->lpo_line);
539 holdtime = nanoseconds() - l->lpo_acqtime;
543 * Record if the lock has been held longer now than ever
546 if (holdtime > lp->cnt_max)
547 lp->cnt_max = holdtime;
548 if (l->lpo_waittime > lp->cnt_wait_max)
549 lp->cnt_wait_max = l->lpo_waittime;
550 lp->cnt_tot += holdtime;
551 lp->cnt_wait += l->lpo_waittime;
552 lp->cnt_contest_locking += l->lpo_contest_locking;
553 lp->cnt_cur += l->lpo_cnt;
555 LIST_REMOVE(l, lpo_link);
556 type = &lp_cpu[PCPU_GET(cpuid)]->lpc_types[spin];
557 LIST_INSERT_HEAD(&type->lpt_lpoalloc, l, lpo_link);
562 SYSCTL_NODE(_debug, OID_AUTO, lock, CTLFLAG_RD, NULL, "lock debugging");
563 SYSCTL_NODE(_debug_lock, OID_AUTO, prof, CTLFLAG_RD, NULL, "lock profiling");
564 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipspin, CTLFLAG_RW,
565 &lock_prof_skipspin, 0, "Skip profiling on spinlocks.");
566 SYSCTL_INT(_debug_lock_prof, OID_AUTO, skipcount, CTLFLAG_RW,
567 &lock_prof_skipcount, 0, "Sample approximately every N lock acquisitions.");
568 SYSCTL_INT(_debug_lock_prof, OID_AUTO, rejected, CTLFLAG_RD,
569 &lock_prof_rejected, 0, "Number of rejected profiling records");
570 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, stats, CTLTYPE_STRING | CTLFLAG_RD,
571 NULL, 0, dump_lock_prof_stats, "A", "Lock profiling statistics");
572 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, reset, CTLTYPE_INT | CTLFLAG_RW,
573 NULL, 0, reset_lock_prof_stats, "I", "Reset lock profiling statistics");
574 SYSCTL_PROC(_debug_lock_prof, OID_AUTO, enable, CTLTYPE_INT | CTLFLAG_RW,
575 NULL, 0, enable_lock_prof, "I", "Enable lock profiling");