bsd/dev/dtrace/lockprof.c

   1 /*
   2  * Copyright (c) 2018 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <sys/dtrace.h>
  29 #include <sys/dtrace_impl.h>
  30 #include <kern/lock_group.h>
  31 #include <kern/lock_stat.h>
  32
  33 #if LOCK_STATS
  34 #define SPIN_HELD 0
  35 #define SPIN_MISS 1
  36 #define SPIN_SPIN 2
  37
  38 #define SPIN_HELD_PREFIX "spin-held-"
  39 #define SPIN_MISS_PREFIX "spin-miss-"
  40 #define SPIN_SPIN_PREFIX "spin-spin-"
  41
  42 #define LOCKGROUPSTAT_AFRAMES 1
  43 #define LOCKGROUPSTAT_LEN 64
  44
  45 static dtrace_provider_id_t lockprof_id;
  46
  47 decl_lck_mtx_data(extern, lck_grp_lock)
  48 extern queue_head_t lck_grp_queue;
  49 extern unsigned int lck_grp_cnt;
  50
  51 #define LOCKPROF_MAX 10000 /* maximum number of lockprof probes */
  52 static uint32_t lockprof_count; /* current number of lockprof probes */
  53
  54 static const struct {
  55         int kind;
  56         const char *prefix;
  57         bool time_event;
  58 } events[] = {
  59         {SPIN_HELD, SPIN_HELD_PREFIX, false},
  60         {SPIN_MISS, SPIN_MISS_PREFIX, false},
  61         {SPIN_SPIN, SPIN_SPIN_PREFIX, true},
  62         {0, NULL, false}
  63 };
  64
  65 const static int hold_defaults[] = {
  66         100, 1000
  67 };
  68
  69 const static struct {
  70         unsigned int time;
  71         const char *suffix;
  72         uint64_t mult;
  73 } cont_defaults[] = {
  74         {100, "ms", NANOSEC / MILLISEC}
  75 };
  76
  77 typedef struct lockprof_probe {
  78         int lockprof_kind;
  79         dtrace_id_t lockprof_id;
  80         uint64_t lockprof_limit;
  81         lck_grp_t *lockprof_grp;
  82 } lockprof_probe_t;
  83
  84 void
  85 lockprof_invoke(lck_grp_t *grp, lck_grp_stat_t *stat, uint64_t val)
  86 {
  87         dtrace_probe(stat->lgs_probeid, (uintptr_t)grp, val, 0, 0, 0);
  88 }
  89
  90 static void
  91 probe_create(int kind, const char *suffix, const char *grp_name, uint64_t count, uint64_t mult)
  92 {
  93         char name[LOCKGROUPSTAT_LEN];
  94         lck_mtx_lock(&lck_grp_lock);
  95         lck_grp_t *grp = (lck_grp_t*)queue_first(&lck_grp_queue);
  96         uint64_t limit = count * mult;
  97
  98         if (events[kind].time_event) {
  99                 nanoseconds_to_absolutetime(limit, &limit);
 100         }
 101
 102         for (unsigned int i = 0; i < lck_grp_cnt; i++, grp = (lck_grp_t*)queue_next((queue_entry_t)grp)) {
 103                 if (!grp_name || grp_name[0] == '\0' || strcmp(grp_name, grp->lck_grp_name) == 0) {
 104                         snprintf(name, sizeof(name), "%s%llu%s", events[kind].prefix, count, suffix ?: "");
 105
 106                         if (dtrace_probe_lookup(lockprof_id, grp->lck_grp_name, NULL, name) != 0) {
 107                                 continue;
 108                         }
 109                         if (lockprof_count >= LOCKPROF_MAX) {
 110                                 break;
 111                         }
 112
 113                         lockprof_probe_t *probe = kmem_zalloc(sizeof(lockprof_probe_t), KM_SLEEP);
 114                         probe->lockprof_kind = kind;
 115                         probe->lockprof_limit = limit;
 116                         probe->lockprof_grp = grp;
 117
 118                         probe->lockprof_id = dtrace_probe_create(lockprof_id, grp->lck_grp_name, NULL, name,
 119                             LOCKGROUPSTAT_AFRAMES, probe);
 120
 121                         lockprof_count++;
 122                 }
 123         }
 124         lck_mtx_unlock(&lck_grp_lock);
 125 }
 126
 127 static void
 128 lockprof_provide(void *arg, const dtrace_probedesc_t *desc)
 129 {
 130 #pragma unused(arg)
 131         size_t event_id, i, len;
 132
 133         if (desc == NULL) {
 134                 for (i = 0; i < sizeof(hold_defaults) / sizeof(hold_defaults[0]); i++) {
 135                         probe_create(SPIN_HELD, NULL, NULL, hold_defaults[i], 1);
 136                         probe_create(SPIN_MISS, NULL, NULL, hold_defaults[i], 1);
 137                 }
 138                 for (i = 0; i < sizeof(cont_defaults) / sizeof(cont_defaults[0]); i++) {
 139                         probe_create(SPIN_SPIN, cont_defaults[i].suffix, NULL, cont_defaults[i].time, cont_defaults[i].mult);
 140                 }
 141                 return;
 142         }
 143
 144         const char *name, *suffix = NULL;
 145         hrtime_t val = 0, mult = 1;
 146
 147         const struct {
 148                 const char *name;
 149                 hrtime_t mult;
 150         } suffixes[] = {
 151                 { "us", NANOSEC / MICROSEC },
 152                 { "usec", NANOSEC / MICROSEC },
 153                 { "ms", NANOSEC / MILLISEC },
 154                 { "msec", NANOSEC / MILLISEC },
 155                 { "s", NANOSEC / SEC },
 156                 { "sec", NANOSEC / SEC },
 157                 { NULL, 0 }
 158         };
 159
 160         name = desc->dtpd_name;
 161
 162         for (event_id = 0; events[event_id].prefix != NULL; event_id++) {
 163                 len = strlen(events[event_id].prefix);
 164
 165                 if (strncmp(name, events[event_id].prefix, len) != 0) {
 166                         continue;
 167                 }
 168                 break;
 169         }
 170
 171         if (events[event_id].prefix == NULL) {
 172                 return;
 173         }
 174
 175
 176         /*
 177          * We need to start before any time suffix.
 178          */
 179         for (i = strlen(name); i >= len; i--) {
 180                 if (name[i] >= '0' && name[i] <= '9') {
 181                         break;
 182                 }
 183                 suffix = &name[i];
 184         }
 185
 186         /*
 187          * Now determine the numerical value present in the probe name.
 188          */
 189         for (uint64_t m = 1; i >= len; i--) {
 190                 if (name[i] < '0' || name[i] > '9') {
 191                         return;
 192                 }
 193
 194                 val += (name[i] - '0') * m;
 195                 m *= (hrtime_t)10;
 196         }
 197
 198         if (val == 0) {
 199                 return;
 200         }
 201
 202         if (events[event_id].time_event) {
 203                 for (i = 0, mult = 0; suffixes[i].name != NULL; i++) {
 204                         if (strncasecmp(suffixes[i].name, suffix, strlen(suffixes[i].name) + 1) == 0) {
 205                                 mult = suffixes[i].mult;
 206                                 break;
 207                         }
 208                 }
 209                 if (suffixes[i].name == NULL) {
 210                         return;
 211                 }
 212         } else if (*suffix != '\0') {
 213                 return;
 214         }
 215
 216         probe_create(events[event_id].kind, suffix, desc->dtpd_mod, val, mult);
 217 }
 218
 219
 220 static lck_grp_stat_t*
 221 lockprof_stat(lck_grp_t *grp, int kind)
 222 {
 223         switch (kind) {
 224         case SPIN_HELD:
 225                 return &grp->lck_grp_stats.lgss_spin_held;
 226         case SPIN_MISS:
 227                 return &grp->lck_grp_stats.lgss_spin_miss;
 228         case SPIN_SPIN:
 229                 return &grp->lck_grp_stats.lgss_spin_spin;
 230         default:
 231                 return NULL;
 232         }
 233 }
 234
 235 static int
 236 lockprof_enable(void *arg, dtrace_id_t id, void *parg)
 237 {
 238 #pragma unused(arg, id, parg)
 239         lockprof_probe_t *probe = (lockprof_probe_t*)parg;
 240         lck_grp_t *grp = probe->lockprof_grp;
 241         lck_grp_stat_t *stat;
 242
 243         if (grp == NULL) {
 244                 return -1;
 245         }
 246
 247         if ((stat = lockprof_stat(grp, probe->lockprof_kind)) == NULL) {
 248                 return -1;
 249         }
 250
 251         /*
 252          * lockprof_enable/disable are called with
 253          * dtrace_lock held
 254          */
 255         if (stat->lgs_limit != 0) {
 256                 return -1;
 257         }
 258
 259         stat->lgs_limit = probe->lockprof_limit;
 260         stat->lgs_enablings++;
 261         stat->lgs_probeid = probe->lockprof_id;
 262
 263         return 0;
 264 }
 265
 266 static void
 267 lockprof_disable(void *arg, dtrace_id_t id, void *parg)
 268 {
 269 #pragma unused(arg, id)
 270         lockprof_probe_t *probe = (lockprof_probe_t*)parg;
 271         lck_grp_t *grp = probe->lockprof_grp;
 272         lck_grp_stat_t *stat;
 273
 274         if (grp == NULL) {
 275                 return;
 276         }
 277
 278         if ((stat = lockprof_stat(grp, probe->lockprof_kind)) == NULL) {
 279                 return;
 280         }
 281
 282         if (stat->lgs_limit == 0 || stat->lgs_enablings == 0) {
 283                 return;
 284         }
 285
 286         stat->lgs_limit = 0;
 287         stat->lgs_enablings--;
 288         stat->lgs_probeid = 0;
 289 }
 290
 291 static void
 292 lockprof_destroy(void *arg, dtrace_id_t id, void *parg)
 293 {
 294 #pragma unused(arg, id)
 295         lockprof_probe_t *probe = (lockprof_probe_t*)parg;
 296         kmem_free(probe, sizeof(lockprof_probe_t));
 297         lockprof_count--;
 298 }
 299
 300 static void
 301 lockprof_getargdesc(void *arg, dtrace_id_t id, void *parg, dtrace_argdesc_t *desc)
 302 {
 303 #pragma unused(arg, id, parg)
 304         const char *argdesc = NULL;
 305         switch (desc->dtargd_ndx) {
 306         case 0:
 307                 argdesc = "lck_grp_t*";
 308                 break;
 309         case 1:
 310                 argdesc = "uint64_t";
 311                 break;
 312         }
 313
 314         if (argdesc) {
 315                 strlcpy(desc->dtargd_native, argdesc, DTRACE_ARGTYPELEN);
 316         } else {
 317                 desc->dtargd_ndx = DTRACE_ARGNONE;
 318         }
 319 }
 320 static dtrace_pattr_t lockprof_attr = {
 321         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 322         { DTRACE_STABILITY_UNSTABLE, DTRACE_STABILITY_UNSTABLE, DTRACE_CLASS_UNKNOWN },
 323         { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 324         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 325         { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 326 };
 327
 328 static dtrace_pops_t lockprof_pops = {
 329         .dtps_provide =         lockprof_provide,
 330         .dtps_provide_module =  NULL,
 331         .dtps_enable =          lockprof_enable,
 332         .dtps_disable =         lockprof_disable,
 333         .dtps_suspend =         NULL,
 334         .dtps_resume =          NULL,
 335         .dtps_getargdesc =      lockprof_getargdesc,
 336         .dtps_getargval =       NULL,
 337         .dtps_usermode =        NULL,
 338         .dtps_destroy =         lockprof_destroy
 339 };
 340 #endif /* LOCK_STATS */
 341 void lockprof_init(void);
 342 void
 343 lockprof_init(void)
 344 {
 345 #if LOCK_STATS
 346         dtrace_register("lockprof", &lockprof_attr,
 347             DTRACE_PRIV_KERNEL, NULL,
 348             &lockprof_pops, NULL, &lockprof_id);
 349 #endif /* LOCK_STATS */
 350 }