sys/cddl/contrib/opensolaris/uts/common/dtrace/profile.c

   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 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include <sys/errno.h>
  29 #include <sys/stat.h>
  30 #include <sys/modctl.h>
  31 #include <sys/conf.h>
  32 #include <sys/systm.h>
  33 #include <sys/ddi.h>
  34 #include <sys/sunddi.h>
  35 #include <sys/cpuvar.h>
  36 #include <sys/kmem.h>
  37 #include <sys/strsubr.h>
  38 #include <sys/dtrace.h>
  39 #include <sys/cyclic.h>
  40 #include <sys/atomic.h>
  41
  42 static dev_info_t *profile_devi;
  43 static dtrace_provider_id_t profile_id;
  44
  45 /*
  46  * Regardless of platform, the stack frames look like this in the case of the
  47  * profile provider:
  48  *
  49  *      profile_fire
  50  *      cyclic_expire
  51  *      cyclic_fire
  52  *      [ cbe ]
  53  *      [ interrupt code ]
  54  *
  55  * On x86, there are five frames from the generic interrupt code; further, the
  56  * interrupted instruction appears as its own stack frame, giving us a total of
  57  * 10.
  58  *
  59  * On SPARC, the picture is further complicated because the compiler
  60  * optimizes away tail-calls -- so the following frames are optimized away:
  61  *
  62  *      profile_fire
  63  *      cyclic_expire
  64  *
  65  * This gives three frames.  However, on DEBUG kernels, the cyclic_expire
  66  * frame cannot be tail-call eliminated, yielding four frames in this case.
  67  *
  68  * All of the above constraints lead to the mess below.  Yes, the profile
  69  * provider should ideally figure this out on-the-fly by hitting one of its own
  70  * probes and then walking its own stack trace.  This is complicated, however,
  71  * and the static definition doesn't seem to be overly brittle.  Still, we
  72  * allow for a manual override in case we get it completely wrong.
  73  */
  74 #ifdef __x86
  75 #define PROF_ARTIFICIAL_FRAMES  10
  76 #else
  77 #ifdef __sparc
  78 #ifdef DEBUG
  79 #define PROF_ARTIFICIAL_FRAMES  4
  80 #else
  81 #define PROF_ARTIFICIAL_FRAMES  3
  82 #endif
  83 #endif
  84 #endif
  85
  86 #define PROF_NAMELEN            15
  87
  88 #define PROF_PROFILE            0
  89 #define PROF_TICK               1
  90 #define PROF_PREFIX_PROFILE     "profile-"
  91 #define PROF_PREFIX_TICK        "tick-"
  92
  93 typedef struct profile_probe {
  94         char            prof_name[PROF_NAMELEN];
  95         dtrace_id_t     prof_id;
  96         int             prof_kind;
  97         hrtime_t        prof_interval;
  98         cyclic_id_t     prof_cyclic;
  99 } profile_probe_t;
 100
 101 typedef struct profile_probe_percpu {
 102         hrtime_t        profc_expected;
 103         hrtime_t        profc_interval;
 104         profile_probe_t *profc_probe;
 105 } profile_probe_percpu_t;
 106
 107 hrtime_t        profile_interval_min = NANOSEC / 5000;          /* 5000 hz */
 108 int             profile_aframes = 0;                            /* override */
 109
 110 static int profile_rates[] = {
 111     97, 199, 499, 997, 1999,
 112     4001, 4999, 0, 0, 0,
 113     0, 0, 0, 0, 0,
 114     0, 0, 0, 0, 0
 115 };
 116
 117 static int profile_ticks[] = {
 118     1, 10, 100, 500, 1000,
 119     5000, 0, 0, 0, 0,
 120     0, 0, 0, 0, 0
 121 };
 122
 123 /*
 124  * profile_max defines the upper bound on the number of profile probes that
 125  * can exist (this is to prevent malicious or clumsy users from exhausing
 126  * system resources by creating a slew of profile probes). At mod load time,
 127  * this gets its value from PROFILE_MAX_DEFAULT or profile-max-probes if it's
 128  * present in the profile.conf file.
 129  */
 130 #define PROFILE_MAX_DEFAULT     1000    /* default max. number of probes */
 131 static uint32_t profile_max;            /* maximum number of profile probes */
 132 static uint32_t profile_total;  /* current number of profile probes */
 133
 134 static void
 135 profile_fire(void *arg)
 136 {
 137         profile_probe_percpu_t *pcpu = arg;
 138         profile_probe_t *prof = pcpu->profc_probe;
 139         hrtime_t late;
 140
 141         late = dtrace_gethrtime() - pcpu->profc_expected;
 142         pcpu->profc_expected += pcpu->profc_interval;
 143
 144         dtrace_probe(prof->prof_id, CPU->cpu_profile_pc,
 145             CPU->cpu_profile_upc, late, 0, 0);
 146 }
 147
 148 static void
 149 profile_tick(void *arg)
 150 {
 151         profile_probe_t *prof = arg;
 152
 153         dtrace_probe(prof->prof_id, CPU->cpu_profile_pc,
 154             CPU->cpu_profile_upc, 0, 0, 0);
 155 }
 156
 157 static void
 158 profile_create(hrtime_t interval, const char *name, int kind)
 159 {
 160         profile_probe_t *prof;
 161         int nr_frames = PROF_ARTIFICIAL_FRAMES + dtrace_mach_aframes();
 162
 163         if (profile_aframes)
 164                 nr_frames = profile_aframes;
 165
 166         if (interval < profile_interval_min)
 167                 return;
 168
 169         if (dtrace_probe_lookup(profile_id, NULL, NULL, name) != 0)
 170                 return;
 171
 172         atomic_add_32(&profile_total, 1);
 173         if (profile_total > profile_max) {
 174                 atomic_add_32(&profile_total, -1);
 175                 return;
 176         }
 177
 178         prof = kmem_zalloc(sizeof (profile_probe_t), KM_SLEEP);
 179         (void) strcpy(prof->prof_name, name);
 180         prof->prof_interval = interval;
 181         prof->prof_cyclic = CYCLIC_NONE;
 182         prof->prof_kind = kind;
 183         prof->prof_id = dtrace_probe_create(profile_id,
 184             NULL, NULL, name, nr_frames, prof);
 185 }
 186
 187 /*ARGSUSED*/
 188 static void
 189 profile_provide(void *arg, const dtrace_probedesc_t *desc)
 190 {
 191         int i, j, rate, kind;
 192         hrtime_t val = 0, mult = 1, len;
 193         const char *name, *suffix = NULL;
 194
 195         const struct {
 196                 char *prefix;
 197                 int kind;
 198         } types[] = {
 199                 { PROF_PREFIX_PROFILE, PROF_PROFILE },
 200                 { PROF_PREFIX_TICK, PROF_TICK },
 201                 { NULL, NULL }
 202         };
 203
 204         const struct {
 205                 char *name;
 206                 hrtime_t mult;
 207         } suffixes[] = {
 208                 { "ns",         NANOSEC / NANOSEC },
 209                 { "nsec",       NANOSEC / NANOSEC },
 210                 { "us",         NANOSEC / MICROSEC },
 211                 { "usec",       NANOSEC / MICROSEC },
 212                 { "ms",         NANOSEC / MILLISEC },
 213                 { "msec",       NANOSEC / MILLISEC },
 214                 { "s",          NANOSEC / SEC },
 215                 { "sec",        NANOSEC / SEC },
 216                 { "m",          NANOSEC * (hrtime_t)60 },
 217                 { "min",        NANOSEC * (hrtime_t)60 },
 218                 { "h",          NANOSEC * (hrtime_t)(60 * 60) },
 219                 { "hour",       NANOSEC * (hrtime_t)(60 * 60) },
 220                 { "d",          NANOSEC * (hrtime_t)(24 * 60 * 60) },
 221                 { "day",        NANOSEC * (hrtime_t)(24 * 60 * 60) },
 222                 { "hz",         0 },
 223                 { NULL }
 224         };
 225
 226         if (desc == NULL) {
 227                 char n[PROF_NAMELEN];
 228
 229                 /*
 230                  * If no description was provided, provide all of our probes.
 231                  */
 232                 for (i = 0; i < sizeof (profile_rates) / sizeof (int); i++) {
 233                         if ((rate = profile_rates[i]) == 0)
 234                                 continue;
 235
 236                         (void) snprintf(n, PROF_NAMELEN, "%s%d",
 237                             PROF_PREFIX_PROFILE, rate);
 238                         profile_create(NANOSEC / rate, n, PROF_PROFILE);
 239                 }
 240
 241                 for (i = 0; i < sizeof (profile_ticks) / sizeof (int); i++) {
 242                         if ((rate = profile_ticks[i]) == 0)
 243                                 continue;
 244
 245                         (void) snprintf(n, PROF_NAMELEN, "%s%d",
 246                             PROF_PREFIX_TICK, rate);
 247                         profile_create(NANOSEC / rate, n, PROF_TICK);
 248                 }
 249
 250                 return;
 251         }
 252
 253         name = desc->dtpd_name;
 254
 255         for (i = 0; types[i].prefix != NULL; i++) {
 256                 len = strlen(types[i].prefix);
 257
 258                 if (strncmp(name, types[i].prefix, len) != 0)
 259                         continue;
 260                 break;
 261         }
 262
 263         if (types[i].prefix == NULL)
 264                 return;
 265
 266         kind = types[i].kind;
 267         j = strlen(name) - len;
 268
 269         /*
 270          * We need to start before any time suffix.
 271          */
 272         for (j = strlen(name); j >= len; j--) {
 273                 if (name[j] >= '0' && name[j] <= '9')
 274                         break;
 275                 suffix = &name[j];
 276         }
 277
 278         ASSERT(suffix != NULL);
 279
 280         /*
 281          * Now determine the numerical value present in the probe name.
 282          */
 283         for (; j >= len; j--) {
 284                 if (name[j] < '0' || name[j] > '9')
 285                         return;
 286
 287                 val += (name[j] - '0') * mult;
 288                 mult *= (hrtime_t)10;
 289         }
 290
 291         if (val == 0)
 292                 return;
 293
 294         /*
 295          * Look-up the suffix to determine the multiplier.
 296          */
 297         for (i = 0, mult = 0; suffixes[i].name != NULL; i++) {
 298                 if (strcasecmp(suffixes[i].name, suffix) == 0) {
 299                         mult = suffixes[i].mult;
 300                         break;
 301                 }
 302         }
 303
 304         if (suffixes[i].name == NULL && *suffix != '\0')
 305                 return;
 306
 307         if (mult == 0) {
 308                 /*
 309                  * The default is frequency-per-second.
 310                  */
 311                 val = NANOSEC / val;
 312         } else {
 313                 val *= mult;
 314         }
 315
 316         profile_create(val, name, kind);
 317 }
 318
 319 /*ARGSUSED*/
 320 static void
 321 profile_destroy(void *arg, dtrace_id_t id, void *parg)
 322 {
 323         profile_probe_t *prof = parg;
 324
 325         ASSERT(prof->prof_cyclic == CYCLIC_NONE);
 326         kmem_free(prof, sizeof (profile_probe_t));
 327
 328         ASSERT(profile_total >= 1);
 329         atomic_add_32(&profile_total, -1);
 330 }
 331
 332 /*ARGSUSED*/
 333 static void
 334 profile_online(void *arg, cpu_t *cpu, cyc_handler_t *hdlr, cyc_time_t *when)
 335 {
 336         profile_probe_t *prof = arg;
 337         profile_probe_percpu_t *pcpu;
 338
 339         pcpu = kmem_zalloc(sizeof (profile_probe_percpu_t), KM_SLEEP);
 340         pcpu->profc_probe = prof;
 341
 342         hdlr->cyh_func = profile_fire;
 343         hdlr->cyh_arg = pcpu;
 344         hdlr->cyh_level = CY_HIGH_LEVEL;
 345
 346         when->cyt_interval = prof->prof_interval;
 347         when->cyt_when = dtrace_gethrtime() + when->cyt_interval;
 348
 349         pcpu->profc_expected = when->cyt_when;
 350         pcpu->profc_interval = when->cyt_interval;
 351 }
 352
 353 /*ARGSUSED*/
 354 static void
 355 profile_offline(void *arg, cpu_t *cpu, void *oarg)
 356 {
 357         profile_probe_percpu_t *pcpu = oarg;
 358
 359         ASSERT(pcpu->profc_probe == arg);
 360         kmem_free(pcpu, sizeof (profile_probe_percpu_t));
 361 }
 362
 363 /*ARGSUSED*/
 364 static void
 365 profile_enable(void *arg, dtrace_id_t id, void *parg)
 366 {
 367         profile_probe_t *prof = parg;
 368         cyc_omni_handler_t omni;
 369         cyc_handler_t hdlr;
 370         cyc_time_t when;
 371
 372         ASSERT(prof->prof_interval != 0);
 373         ASSERT(MUTEX_HELD(&cpu_lock));
 374
 375         if (prof->prof_kind == PROF_TICK) {
 376                 hdlr.cyh_func = profile_tick;
 377                 hdlr.cyh_arg = prof;
 378                 hdlr.cyh_level = CY_HIGH_LEVEL;
 379
 380                 when.cyt_interval = prof->prof_interval;
 381                 when.cyt_when = dtrace_gethrtime() + when.cyt_interval;
 382         } else {
 383                 ASSERT(prof->prof_kind == PROF_PROFILE);
 384                 omni.cyo_online = profile_online;
 385                 omni.cyo_offline = profile_offline;
 386                 omni.cyo_arg = prof;
 387         }
 388
 389         if (prof->prof_kind == PROF_TICK) {
 390                 prof->prof_cyclic = cyclic_add(&hdlr, &when);
 391         } else {
 392                 prof->prof_cyclic = cyclic_add_omni(&omni);
 393         }
 394 }
 395
 396 /*ARGSUSED*/
 397 static void
 398 profile_disable(void *arg, dtrace_id_t id, void *parg)
 399 {
 400         profile_probe_t *prof = parg;
 401
 402         ASSERT(prof->prof_cyclic != CYCLIC_NONE);
 403         ASSERT(MUTEX_HELD(&cpu_lock));
 404
 405         cyclic_remove(prof->prof_cyclic);
 406         prof->prof_cyclic = CYCLIC_NONE;
 407 }
 408
 409 /*ARGSUSED*/
 410 static int
 411 profile_usermode(void *arg, dtrace_id_t id, void *parg)
 412 {
 413         return (CPU->cpu_profile_pc == 0);
 414 }
 415
 416 static dtrace_pattr_t profile_attr = {
 417 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 418 { DTRACE_STABILITY_UNSTABLE, DTRACE_STABILITY_UNSTABLE, DTRACE_CLASS_UNKNOWN },
 419 { DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
 420 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 421 { DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_COMMON },
 422 };
 423
 424 static dtrace_pops_t profile_pops = {
 425         profile_provide,
 426         NULL,
 427         profile_enable,
 428         profile_disable,
 429         NULL,
 430         NULL,
 431         NULL,
 432         NULL,
 433         profile_usermode,
 434         profile_destroy
 435 };
 436
 437 static int
 438 profile_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
 439 {
 440         switch (cmd) {
 441         case DDI_ATTACH:
 442                 break;
 443         case DDI_RESUME:
 444                 return (DDI_SUCCESS);
 445         default:
 446                 return (DDI_FAILURE);
 447         }
 448
 449         if (ddi_create_minor_node(devi, "profile", S_IFCHR, 0,
 450             DDI_PSEUDO, NULL) == DDI_FAILURE ||
 451             dtrace_register("profile", &profile_attr,
 452             DTRACE_PRIV_KERNEL | DTRACE_PRIV_USER, NULL,
 453             &profile_pops, NULL, &profile_id) != 0) {
 454                 ddi_remove_minor_node(devi, NULL);
 455                 return (DDI_FAILURE);
 456         }
 457
 458         profile_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
 459             "profile-max-probes", PROFILE_MAX_DEFAULT);
 460
 461         ddi_report_dev(devi);
 462         profile_devi = devi;
 463         return (DDI_SUCCESS);
 464 }
 465
 466 static int
 467 profile_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
 468 {
 469         switch (cmd) {
 470         case DDI_DETACH:
 471                 break;
 472         case DDI_SUSPEND:
 473                 return (DDI_SUCCESS);
 474         default:
 475                 return (DDI_FAILURE);
 476         }
 477
 478         if (dtrace_unregister(profile_id) != 0)
 479                 return (DDI_FAILURE);
 480
 481         ddi_remove_minor_node(devi, NULL);
 482         return (DDI_SUCCESS);
 483 }
 484
 485 /*ARGSUSED*/
 486 static int
 487 profile_info(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result)
 488 {
 489         int error;
 490
 491         switch (infocmd) {
 492         case DDI_INFO_DEVT2DEVINFO:
 493                 *result = (void *)profile_devi;
 494                 error = DDI_SUCCESS;
 495                 break;
 496         case DDI_INFO_DEVT2INSTANCE:
 497                 *result = (void *)0;
 498                 error = DDI_SUCCESS;
 499                 break;
 500         default:
 501                 error = DDI_FAILURE;
 502         }
 503         return (error);
 504 }
 505
 506 /*ARGSUSED*/
 507 static int
 508 profile_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
 509 {
 510         return (0);
 511 }
 512
 513 static struct cb_ops profile_cb_ops = {
 514         profile_open,           /* open */
 515         nodev,                  /* close */
 516         nulldev,                /* strategy */
 517         nulldev,                /* print */
 518         nodev,                  /* dump */
 519         nodev,                  /* read */
 520         nodev,                  /* write */
 521         nodev,                  /* ioctl */
 522         nodev,                  /* devmap */
 523         nodev,                  /* mmap */
 524         nodev,                  /* segmap */
 525         nochpoll,               /* poll */
 526         ddi_prop_op,            /* cb_prop_op */
 527         0,                      /* streamtab  */
 528         D_NEW | D_MP            /* Driver compatibility flag */
 529 };
 530
 531 static struct dev_ops profile_ops = {
 532         DEVO_REV,               /* devo_rev, */
 533         0,                      /* refcnt  */
 534         profile_info,           /* get_dev_info */
 535         nulldev,                /* identify */
 536         nulldev,                /* probe */
 537         profile_attach,         /* attach */
 538         profile_detach,         /* detach */
 539         nodev,                  /* reset */
 540         &profile_cb_ops,        /* driver operations */
 541         NULL,                   /* bus operations */
 542         nodev                   /* dev power */
 543 };
 544
 545 /*
 546  * Module linkage information for the kernel.
 547  */
 548 static struct modldrv modldrv = {
 549         &mod_driverops,         /* module type (this is a pseudo driver) */
 550         "Profile Interrupt Tracing",    /* name of module */
 551         &profile_ops,           /* driver ops */
 552 };
 553
 554 static struct modlinkage modlinkage = {
 555         MODREV_1,
 556         (void *)&modldrv,
 557         NULL
 558 };
 559
 560 int
 561 _init(void)
 562 {
 563         return (mod_install(&modlinkage));
 564 }
 565
 566 int
 567 _info(struct modinfo *modinfop)
 568 {
 569         return (mod_info(&modlinkage, modinfop));
 570 }
 571
 572 int
 573 _fini(void)
 574 {
 575         return (mod_remove(&modlinkage));
 576 }