1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008-2022 NetApp, Inc. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/param.h> 28 #include <sys/systm.h> 29 #include <sys/boottrace.h> 30 #include <sys/kernel.h> 31 #include <sys/malloc.h> 32 #include <sys/pcpu.h> 33 #include <sys/proc.h> 34 #include <sys/resourcevar.h> 35 #include <sys/sbuf.h> 36 #include <sys/syscallsubr.h> 37 #include <sys/sysctl.h> 38 #include <sys/time.h> 39 40 #include <machine/stdarg.h> 41 42 #define dprintf(fmt, ...) \ 43 do { \ 44 if (dotrace_debugging) \ 45 printf(fmt, ##__VA_ARGS__); \ 46 } while (0); 47 48 static MALLOC_DEFINE(M_BOOTTRACE, "boottrace", "memory for boot tracing"); 49 50 #define BT_TABLE_DEFSIZE 3000 51 #define BT_TABLE_RUNSIZE 2000 52 #define BT_TABLE_SHTSIZE 1000 53 #define BT_TABLE_MINSIZE 500 54 55 /* 56 * Boot-time & shutdown-time event. 57 */ 58 struct bt_event { 59 uint64_t tsc; /* Timestamp */ 60 uint64_t tick; /* Kernel tick */ 61 uint64_t cputime; /* Microseconds of process CPU time */ 62 uint32_t cpuid; /* CPU on which the event ran */ 63 uint32_t inblock; /* # of blocks in */ 64 uint32_t oublock; /* # of blocks out */ 65 pid_t pid; /* Current PID */ 66 char name[BT_EVENT_NAMELEN]; /* Event name */ 67 char tdname[BT_EVENT_TDNAMELEN]; /* Thread name */ 68 }; 69 70 struct bt_table { 71 uint32_t size; /* Trace table size */ 72 uint32_t curr; /* Trace entry to use */ 73 uint32_t wrap; /* Wrap-around, instead of dropping */ 74 uint32_t drops_early; /* Trace entries dropped before init */ 75 uint32_t drops_full; /* Trace entries dropped after full */ 76 struct bt_event *table; 77 }; 78 79 /* Boot-time tracing */ 80 static struct bt_table bt; 81 82 /* Run-time tracing */ 83 static struct bt_table rt; 84 85 /* Shutdown-time tracing */ 86 static struct bt_table st; 87 88 /* Set when system boot is complete, and we've switched to runtime tracing. */ 89 static bool bootdone; 90 91 /* Set when system shutdown has started. */ 92 static bool shutdown; 93 94 /* Turn on dotrace() debug logging to console. */ 95 static bool dotrace_debugging; 96 TUNABLE_BOOL("debug.boottrace.dotrace_debugging", &dotrace_debugging); 97 98 /* Trace kernel events */ 99 static bool dotrace_kernel = true; 100 TUNABLE_BOOL("kern.boottrace.dotrace_kernel", &dotrace_kernel); 101 102 /* Trace userspace events */ 103 static bool dotrace_user = true; 104 TUNABLE_BOOL("kern.boottrace.dotrace_user", &dotrace_user); 105 106 static int sysctl_log(SYSCTL_HANDLER_ARGS); 107 static int sysctl_boottrace(SYSCTL_HANDLER_ARGS); 108 static int sysctl_runtrace(SYSCTL_HANDLER_ARGS); 109 static int sysctl_shuttrace(SYSCTL_HANDLER_ARGS); 110 static int sysctl_boottrace_reset(SYSCTL_HANDLER_ARGS); 111 112 SYSCTL_NODE(_kern, OID_AUTO, boottrace, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 113 "boottrace statistics"); 114 115 SYSCTL_PROC(_kern_boottrace, OID_AUTO, log, 116 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE | CTLFLAG_SKIP, 117 0, 0, sysctl_log, "A", 118 "Print a log of the boottrace trace data"); 119 SYSCTL_PROC(_kern_boottrace, OID_AUTO, boottrace, 120 CTLTYPE_STRING | CTLFLAG_WR | CTLFLAG_MPSAFE, 121 0, 0, sysctl_boottrace, "A", 122 "Capture a boot-time trace event"); 123 SYSCTL_PROC(_kern_boottrace, OID_AUTO, runtrace, 124 CTLTYPE_STRING | CTLFLAG_WR | CTLFLAG_MPSAFE, 125 0, 0, sysctl_runtrace, "A", 126 "Capture a run-time trace event"); 127 SYSCTL_PROC(_kern_boottrace, OID_AUTO, shuttrace, 128 CTLTYPE_STRING | CTLFLAG_WR | CTLFLAG_MPSAFE, 129 0, 0, sysctl_shuttrace, "A", 130 "Capture a shutdown-time trace event"); 131 SYSCTL_PROC(_kern_boottrace, OID_AUTO, reset, 132 CTLTYPE_INT | CTLFLAG_WR | CTLFLAG_MPSAFE, 133 0, 0, sysctl_boottrace_reset, "A", 134 "Reset run-time tracing table"); 135 136 /* 137 * Global enable. 138 */ 139 bool __read_mostly boottrace_enabled = false; 140 SYSCTL_BOOL(_kern_boottrace, OID_AUTO, enabled, CTLFLAG_RDTUN, 141 &boottrace_enabled, 0, 142 "Boot-time and shutdown-time tracing enabled"); 143 144 /* 145 * Enable dumping of the shutdown trace entries to console. 146 */ 147 bool shutdown_trace = false; 148 SYSCTL_BOOL(_kern_boottrace, OID_AUTO, shutdown_trace, CTLFLAG_RWTUN, 149 &shutdown_trace, 0, 150 "Enable kernel shutdown tracing to the console"); 151 152 /* 153 * Set the delta threshold (ms) below which events are ignored, used in 154 * determining what to dump to the console. 155 */ 156 static int shutdown_trace_threshold; 157 SYSCTL_INT(_kern_boottrace, OID_AUTO, shutdown_trace_threshold, CTLFLAG_RWTUN, 158 &shutdown_trace_threshold, 0, 159 "Tracing threshold (ms) below which tracing is ignored"); 160 161 /* 162 * Dump a trace to buffer or if buffer is NULL to console. 163 * 164 * Non-zero delta_threshold selectively prints entries based on delta 165 * with current and previous entry. Otherwise, delta_threshold of 0 166 * prints every trace entry and delta. 167 * 168 * Output something like this: 169 * 170 * CPU msecs delta process event 171 * 11 1228262715 0 init shutdown pre sync begin 172 * 3 1228265622 2907 init shutdown pre sync complete 173 * 3 1228265623 0 init shutdown turned swap off 174 * 18 1228266466 843 init shutdown unmounted all filesystems 175 * 176 * How to interpret: 177 * 178 * delta column represents the time in milliseconds between this event and the previous. 179 * Usually that means you can take the previous event, current event, match them 180 * up in the code, and whatever lies between is the culprit taking time. 181 * 182 * For example, above: Pre-Sync is taking 2907ms, and something between swap and unmount 183 * filesystems is taking 843 milliseconds. 184 * 185 * An event with a delta of 0 are 'landmark' events that simply exist in the output 186 * for the developer to know where the time measurement begins. The 0 is an arbitrary 187 * number that can effectively be ignored. 188 */ 189 #define BTC_DELTA_PRINT(bte, msecs, delta) do { \ 190 if (sbp) { \ 191 sbuf_printf(sbp, fmt, (bte)->cpuid, msecs, delta, \ 192 (bte)->tdname, (bte)->name, (bte)->pid, \ 193 (bte)->cputime / 1000000, \ 194 ((bte)->cputime % 1000000) / 10000, \ 195 (bte)->inblock, (bte)->oublock); \ 196 } else { \ 197 printf(fmt, (bte)->cpuid, msecs, delta, \ 198 (bte)->tdname, (bte)->name, (bte)->pid, \ 199 (bte)->cputime / 1000000, \ 200 ((bte)->cputime % 1000000) / 10000, \ 201 (bte)->inblock, (bte)->oublock); \ 202 } \ 203 } while (0) 204 205 /* 206 * Print the trace entries to the message buffer, or to an sbuf, if provided. 207 * 208 * Entries with a difference less than dthres will not be printed. 209 */ 210 static void 211 boottrace_display(struct sbuf *sbp, struct bt_table *btp, uint64_t dthres) 212 { 213 struct bt_event *evtp; 214 struct bt_event *last_evtp; 215 uint64_t msecs; 216 uint64_t first_msecs; 217 uint64_t last_msecs; 218 uint64_t dmsecs; 219 uint64_t last_dmsecs; 220 uint64_t total_dmsecs; 221 uint32_t i; 222 uint32_t curr; 223 const char *fmt = "%3u %10llu %10llu %-24s %-40s %5d %4d.%02d %5u %5u\n"; 224 const char *hdr_fmt = "\n\n%3s %10s %10s %-24s %-40s %5s %6s %5s %5s\n"; 225 bool printed; 226 bool last_printed; 227 228 /* Print the header */ 229 if (sbp != NULL) 230 sbuf_printf(sbp, hdr_fmt, 231 "CPU", "msecs", "delta", "process", 232 "event", "PID", "CPUtime", "IBlks", "OBlks"); 233 else 234 printf(hdr_fmt, 235 "CPU", "msecs", "delta", "process", 236 "event", "PID", "CPUtime", "IBlks", "OBlks"); 237 238 first_msecs = 0; 239 last_evtp = NULL; 240 last_msecs = 0; 241 last_dmsecs = 0; 242 last_printed = false; 243 i = curr = btp->curr; 244 245 do { 246 evtp = &btp->table[i]; 247 if (evtp->tsc == 0) 248 goto next; 249 250 msecs = cputick2usec(evtp->tick) / 1000; 251 dmsecs = (last_msecs != 0 && msecs > last_msecs) ? 252 msecs - last_msecs : 0; 253 printed = false; 254 255 /* 256 * If a threshold is defined, start filtering events by the 257 * delta of msecs. 258 */ 259 if (dthres != 0 && (dmsecs > dthres)) { 260 /* 261 * Print the previous entry as a landmark, even if it 262 * falls below the threshold. 263 */ 264 if (last_evtp != NULL && !last_printed) 265 BTC_DELTA_PRINT(last_evtp, last_msecs, 266 last_dmsecs); 267 BTC_DELTA_PRINT(evtp, msecs, dmsecs); 268 printed = true; 269 } else if (dthres == 0) { 270 BTC_DELTA_PRINT(evtp, msecs, dmsecs); 271 printed = true; 272 } 273 if (first_msecs == 0 || msecs < first_msecs) 274 first_msecs = msecs; 275 last_evtp = evtp; 276 last_msecs = msecs; 277 last_dmsecs = dmsecs; 278 last_printed = printed; 279 maybe_yield(); 280 next: 281 i = (i + 1) % btp->size; 282 } while (i != curr); 283 284 total_dmsecs = last_msecs > first_msecs ? 285 (last_msecs - first_msecs) : 0; 286 if (sbp != NULL) 287 sbuf_printf(sbp, "Total measured time: %ju msecs\n", 288 (uintmax_t)total_dmsecs); 289 else 290 printf("Total measured time: %ju msecs\n", 291 (uintmax_t)total_dmsecs); 292 } 293 294 /* 295 * Dump trace table entries to the console, given a delta threshold. 296 */ 297 void 298 boottrace_dump_console(void) 299 { 300 if (!boottrace_enabled) 301 return; 302 303 if (shutdown || rebooting || KERNEL_PANICKED()) { 304 boottrace_display(NULL, &st, shutdown_trace_threshold); 305 } else { 306 boottrace_display(NULL, &bt, 0); 307 boottrace_display(NULL, &rt, 0); 308 } 309 } 310 311 /* 312 * Records a new tracing event to the specified table. 313 * 314 * We don't use a lock because we want this to be callable from interrupt 315 * context. 316 */ 317 static int 318 dotrace(struct bt_table *btp, const char *eventname, const char *tdname) 319 { 320 uint32_t idx, nxt; 321 struct rusage usage; 322 323 MPASS(boottrace_enabled); 324 if (tdname == NULL) 325 tdname = (curproc->p_flag & P_SYSTEM) ? 326 curthread->td_name : curproc->p_comm; 327 328 dprintf("dotrace["); 329 dprintf("cpu=%u, pid=%d, tsc=%ju, tick=%d, td='%s', event='%s'", 330 PCPU_GET(cpuid), curthread->td_proc->p_pid, 331 (uintmax_t)get_cyclecount(), ticks, tdname, eventname); 332 if (btp->table == NULL) { 333 btp->drops_early++; 334 dprintf(", return=ENOSPC_1]\n"); 335 return (ENOSPC); 336 } 337 338 /* Claim a slot in the table. */ 339 do { 340 idx = btp->curr; 341 nxt = (idx + 1) % btp->size; 342 if (nxt == 0 && btp->wrap == 0) { 343 btp->drops_full++; 344 dprintf(", return=ENOSPC_2]\n"); 345 return (ENOSPC); 346 } 347 } while (!atomic_cmpset_int(&btp->curr, idx, nxt)); 348 349 btp->table[idx].cpuid = PCPU_GET(cpuid); 350 btp->table[idx].tsc = get_cyclecount(), 351 btp->table[idx].tick = cpu_ticks(); 352 btp->table[idx].pid = curthread->td_proc->p_pid; 353 354 /* 355 * Get the resource usage for the process. Don't attempt this for the 356 * kernel proc0 or for critical section activities. 357 */ 358 if ((curthread->td_proc == &proc0) || (curthread->td_critnest != 0)) { 359 btp->table[idx].cputime = 0; 360 btp->table[idx].inblock = 0; 361 btp->table[idx].oublock = 0; 362 } else { 363 kern_getrusage(curthread, RUSAGE_CHILDREN, &usage); 364 btp->table[idx].cputime = 365 (uint64_t)(usage.ru_utime.tv_sec * 1000000 + 366 usage.ru_utime.tv_usec + usage.ru_stime.tv_sec * 1000000 + 367 usage.ru_stime.tv_usec); 368 btp->table[idx].inblock = (uint32_t)usage.ru_inblock; 369 btp->table[idx].oublock = (uint32_t)usage.ru_oublock; 370 } 371 strlcpy(btp->table[idx].name, eventname, BT_EVENT_NAMELEN); 372 strlcpy(btp->table[idx].tdname, tdname, BT_EVENT_TDNAMELEN); 373 374 dprintf(", return=0]\n"); 375 return (0); 376 } 377 378 /* 379 * Log various boot-time events, with the trace message encoded using 380 * printf-like arguments. 381 */ 382 int 383 boottrace(const char *tdname, const char *fmt, ...) 384 { 385 char eventname[BT_EVENT_NAMELEN]; 386 struct bt_table *btp; 387 va_list ap; 388 389 if (!dotrace_kernel) 390 return (ENXIO); 391 392 va_start(ap, fmt); 393 vsnprintf(eventname, sizeof(eventname), fmt, ap); 394 va_end(ap); 395 396 btp = &bt; 397 if (bootdone) 398 btp = &rt; 399 if (shutdown || rebooting || KERNEL_PANICKED()) 400 btp = &st; 401 402 return (dotrace(btp, eventname, tdname)); 403 } 404 405 /* 406 * Log a run-time event & switch over to run-time tracing mode. 407 */ 408 static int 409 runtrace(const char *eventname, const char *tdname) 410 { 411 412 bootdone = true; 413 return (dotrace(&rt, eventname, tdname)); 414 } 415 416 /* 417 * Parse a boottrace message from userspace. 418 * 419 * The input from may contain a ':' to denote tdname. If not, tdname is 420 * inferred from the process' name. 421 * 422 * e.g. reboot(8):SIGINT to init(8) 423 */ 424 static void 425 boottrace_parse_message(char *message, char **eventname, char **tdname) 426 { 427 char *delim; 428 429 delim = strchr(message, ':'); 430 if (delim != NULL) { 431 *delim = '\0'; 432 *tdname = message; 433 *eventname = ++delim; 434 } else { 435 *tdname = curproc->p_comm; 436 *eventname = message; 437 } 438 } 439 440 static int 441 _boottrace_sysctl(struct bt_table *btp, struct sysctl_oid *oidp, 442 struct sysctl_req *req) 443 { 444 char message[BT_MSGLEN]; 445 char *eventname, *tdname; 446 int error; 447 448 if (!dotrace_user) 449 return (ENXIO); 450 451 message[0] = '\0'; 452 error = sysctl_handle_string(oidp, message, sizeof(message), req); 453 if (error) 454 return (error); 455 456 boottrace_parse_message(message, &eventname, &tdname); 457 error = dotrace(btp, eventname, tdname); 458 if (error == ENOSPC) { 459 /* Ignore table full error. */ 460 error = 0; 461 } 462 return (error); 463 } 464 465 static int 466 sysctl_log(SYSCTL_HANDLER_ARGS) 467 { 468 struct sbuf *sbuf; 469 int error; 470 471 if (!boottrace_enabled || req->newptr != NULL) 472 return (0); 473 474 sbuf = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND); 475 boottrace_display(sbuf, &bt, 0); 476 boottrace_display(sbuf, &rt, 0); 477 sbuf_finish(sbuf); 478 error = SYSCTL_OUT(req, sbuf_data(sbuf), sbuf_len(sbuf)); 479 sbuf_delete(sbuf); 480 481 return (error); 482 } 483 484 static int 485 sysctl_boottrace(SYSCTL_HANDLER_ARGS) 486 { 487 488 if (!boottrace_enabled) 489 return (0); 490 491 /* No output */ 492 if (req->newptr == NULL) 493 return (0); 494 495 /* Trace to rt if we have reached multi-user. */ 496 return (_boottrace_sysctl(bootdone ? &rt : &bt, oidp, req)); 497 } 498 499 /* 500 * Log a run-time event and switch over to run-time tracing mode. 501 */ 502 static int 503 sysctl_runtrace(SYSCTL_HANDLER_ARGS) 504 { 505 506 if (!boottrace_enabled) 507 return (0); 508 509 /* No output */ 510 if (req->newptr == NULL) 511 return (0); 512 513 bootdone = true; 514 return (_boottrace_sysctl(&rt, oidp, req)); 515 } 516 517 /* 518 * Log a shutdown-time event and switch over to shutdown tracing mode. 519 */ 520 static int 521 sysctl_shuttrace(SYSCTL_HANDLER_ARGS) 522 { 523 524 if (!boottrace_enabled) 525 return (0); 526 527 /* No output */ 528 if (req->newptr == NULL) 529 return (0); 530 531 shutdown = true; 532 return (_boottrace_sysctl(&st, oidp, req)); 533 } 534 535 /* 536 * Reset the runtime tracing buffer. 537 */ 538 void 539 boottrace_reset(const char *actor) 540 { 541 char tmpbuf[64]; 542 543 snprintf(tmpbuf, sizeof(tmpbuf), "reset: %s", actor); 544 runtrace(tmpbuf, NULL); 545 } 546 547 /* 548 * Note that a resize implies a reset, i.e., the index is reset to 0. 549 * We never shrink the array; we can only increase its size. 550 */ 551 int 552 boottrace_resize(u_int newsize) 553 { 554 555 if (newsize <= rt.size) { 556 return (EINVAL); 557 } 558 rt.table = realloc(rt.table, newsize * sizeof(struct bt_event), 559 M_BOOTTRACE, M_WAITOK | M_ZERO); 560 if (rt.table == NULL) 561 return (ENOMEM); 562 563 rt.size = newsize; 564 boottrace_reset("boottrace_resize"); 565 return (0); 566 } 567 568 static int 569 sysctl_boottrace_reset(SYSCTL_HANDLER_ARGS) 570 { 571 572 if (!boottrace_enabled) 573 return (0); 574 575 if (req->newptr != NULL) 576 boottrace_reset("sysctl_boottrace_reset"); 577 578 return (0); 579 } 580 581 static void 582 boottrace_init(void) 583 { 584 585 if (!boottrace_enabled) 586 return; 587 588 /* Boottime trace table */ 589 bt.size = BT_TABLE_DEFSIZE; 590 TUNABLE_INT_FETCH("kern.boottrace.table_size", &bt.size); 591 bt.size = max(bt.size, BT_TABLE_MINSIZE); 592 bt.table = malloc(bt.size * sizeof(struct bt_event), M_BOOTTRACE, 593 M_WAITOK | M_ZERO); 594 595 /* Stick in an initial entry. */ 596 bt.table[0].cpuid = PCPU_GET(cpuid); 597 strlcpy(bt.table[0].tdname, "boottime", BT_EVENT_TDNAMELEN); 598 strlcpy(bt.table[0].name, "initial event", BT_EVENT_NAMELEN); 599 bt.curr = 1; 600 601 /* Run-time trace table (may wrap-around). */ 602 rt.wrap = 1; 603 rt.size = BT_TABLE_RUNSIZE; 604 rt.table = malloc(rt.size * sizeof(struct bt_event), M_BOOTTRACE, 605 M_WAITOK | M_ZERO); 606 607 /* Shutdown trace table */ 608 st.size = BT_TABLE_SHTSIZE; 609 st.table = malloc(st.size * sizeof(struct bt_event), M_BOOTTRACE, 610 M_WAITOK | M_ZERO); 611 } 612 SYSINIT(boottrace, SI_SUB_CPU, SI_ORDER_ANY, boottrace_init, 0); 613