Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_clock.c
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1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include "opt_kdb.h" 43 #include "opt_device_polling.h" 44 #include "opt_hwpmc_hooks.h" 45 #include "opt_ntp.h" 46 #include "opt_watchdog.h" 47 48 #include <sys/param.h> 49 #include <sys/systm.h> 50 #include <sys/callout.h> 51 #include <sys/epoch.h> 52 #include <sys/eventhandler.h> 53 #include <sys/gtaskqueue.h> 54 #include <sys/kdb.h> 55 #include <sys/kernel.h> 56 #include <sys/kthread.h> 57 #include <sys/ktr.h> 58 #include <sys/lock.h> 59 #include <sys/mutex.h> 60 #include <sys/proc.h> 61 #include <sys/resource.h> 62 #include <sys/resourcevar.h> 63 #include <sys/sched.h> 64 #include <sys/sdt.h> 65 #include <sys/signalvar.h> 66 #include <sys/sleepqueue.h> 67 #include <sys/smp.h> 68 #include <vm/vm.h> 69 #include <vm/pmap.h> 70 #include <vm/vm_map.h> 71 #include <sys/sysctl.h> 72 #include <sys/bus.h> 73 #include <sys/interrupt.h> 74 #include <sys/limits.h> 75 #include <sys/timetc.h> 76 77 #ifdef GPROF 78 #include <sys/gmon.h> 79 #endif 80 81 #ifdef HWPMC_HOOKS 82 #include <sys/pmckern.h> 83 PMC_SOFT_DEFINE( , , clock, hard); 84 PMC_SOFT_DEFINE( , , clock, stat); 85 PMC_SOFT_DEFINE_EX( , , clock, prof, \ 86 cpu_startprofclock, cpu_stopprofclock); 87 #endif 88 89 #ifdef DEVICE_POLLING 90 extern void hardclock_device_poll(void); 91 #endif /* DEVICE_POLLING */ 92 93 /* Spin-lock protecting profiling statistics. */ 94 static struct mtx time_lock; 95 96 SDT_PROVIDER_DECLARE(sched); 97 SDT_PROBE_DEFINE2(sched, , , tick, "struct thread *", "struct proc *"); 98 99 static int 100 sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS) 101 { 102 int error; 103 long cp_time[CPUSTATES]; 104 #ifdef SCTL_MASK32 105 int i; 106 unsigned int cp_time32[CPUSTATES]; 107 #endif 108 109 read_cpu_time(cp_time); 110 #ifdef SCTL_MASK32 111 if (req->flags & SCTL_MASK32) { 112 if (!req->oldptr) 113 return SYSCTL_OUT(req, 0, sizeof(cp_time32)); 114 for (i = 0; i < CPUSTATES; i++) 115 cp_time32[i] = (unsigned int)cp_time[i]; 116 error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); 117 } else 118 #endif 119 { 120 if (!req->oldptr) 121 return SYSCTL_OUT(req, 0, sizeof(cp_time)); 122 error = SYSCTL_OUT(req, cp_time, sizeof(cp_time)); 123 } 124 return error; 125 } 126 127 SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 128 0,0, sysctl_kern_cp_time, "LU", "CPU time statistics"); 129 130 static long empty[CPUSTATES]; 131 132 static int 133 sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS) 134 { 135 struct pcpu *pcpu; 136 int error; 137 int c; 138 long *cp_time; 139 #ifdef SCTL_MASK32 140 unsigned int cp_time32[CPUSTATES]; 141 int i; 142 #endif 143 144 if (!req->oldptr) { 145 #ifdef SCTL_MASK32 146 if (req->flags & SCTL_MASK32) 147 return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1)); 148 else 149 #endif 150 return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1)); 151 } 152 for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) { 153 if (!CPU_ABSENT(c)) { 154 pcpu = pcpu_find(c); 155 cp_time = pcpu->pc_cp_time; 156 } else { 157 cp_time = empty; 158 } 159 #ifdef SCTL_MASK32 160 if (req->flags & SCTL_MASK32) { 161 for (i = 0; i < CPUSTATES; i++) 162 cp_time32[i] = (unsigned int)cp_time[i]; 163 error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32)); 164 } else 165 #endif 166 error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES); 167 } 168 return error; 169 } 170 171 SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE, 172 0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics"); 173 174 #ifdef DEADLKRES 175 static const char *blessed[] = { 176 "getblk", 177 "so_snd_sx", 178 "so_rcv_sx", 179 NULL 180 }; 181 static int slptime_threshold = 1800; 182 static int blktime_threshold = 900; 183 static int sleepfreq = 3; 184 185 static void 186 deadlres_td_on_lock(struct proc *p, struct thread *td, int blkticks) 187 { 188 int tticks; 189 190 sx_assert(&allproc_lock, SX_LOCKED); 191 PROC_LOCK_ASSERT(p, MA_OWNED); 192 THREAD_LOCK_ASSERT(td, MA_OWNED); 193 /* 194 * The thread should be blocked on a turnstile, simply check 195 * if the turnstile channel is in good state. 196 */ 197 MPASS(td->td_blocked != NULL); 198 199 tticks = ticks - td->td_blktick; 200 if (tticks > blkticks) 201 /* 202 * Accordingly with provided thresholds, this thread is stuck 203 * for too long on a turnstile. 204 */ 205 panic("%s: possible deadlock detected for %p (%s), " 206 "blocked for %d ticks\n", __func__, 207 td, sched_tdname(td), tticks); 208 } 209 210 static void 211 deadlres_td_sleep_q(struct proc *p, struct thread *td, int slpticks) 212 { 213 const void *wchan; 214 int i, slptype, tticks; 215 216 sx_assert(&allproc_lock, SX_LOCKED); 217 PROC_LOCK_ASSERT(p, MA_OWNED); 218 THREAD_LOCK_ASSERT(td, MA_OWNED); 219 /* 220 * Check if the thread is sleeping on a lock, otherwise skip the check. 221 * Drop the thread lock in order to avoid a LOR with the sleepqueue 222 * spinlock. 223 */ 224 wchan = td->td_wchan; 225 tticks = ticks - td->td_slptick; 226 slptype = sleepq_type(wchan); 227 if ((slptype == SLEEPQ_SX || slptype == SLEEPQ_LK) && 228 tticks > slpticks) { 229 /* 230 * Accordingly with provided thresholds, this thread is stuck 231 * for too long on a sleepqueue. 232 * However, being on a sleepqueue, we might still check for the 233 * blessed list. 234 */ 235 for (i = 0; blessed[i] != NULL; i++) 236 if (!strcmp(blessed[i], td->td_wmesg)) 237 return; 238 239 panic("%s: possible deadlock detected for %p (%s), " 240 "blocked for %d ticks\n", __func__, 241 td, sched_tdname(td), tticks); 242 } 243 } 244 245 static void 246 deadlkres(void) 247 { 248 struct proc *p; 249 struct thread *td; 250 int blkticks, slpticks, tryl; 251 252 tryl = 0; 253 for (;;) { 254 blkticks = blktime_threshold * hz; 255 slpticks = slptime_threshold * hz; 256 257 /* 258 * Avoid to sleep on the sx_lock in order to avoid a 259 * possible priority inversion problem leading to 260 * starvation. 261 * If the lock can't be held after 100 tries, panic. 262 */ 263 if (!sx_try_slock(&allproc_lock)) { 264 if (tryl > 100) 265 panic("%s: possible deadlock detected " 266 "on allproc_lock\n", __func__); 267 tryl++; 268 pause("allproc", sleepfreq * hz); 269 continue; 270 } 271 tryl = 0; 272 FOREACH_PROC_IN_SYSTEM(p) { 273 PROC_LOCK(p); 274 if (p->p_state == PRS_NEW) { 275 PROC_UNLOCK(p); 276 continue; 277 } 278 FOREACH_THREAD_IN_PROC(p, td) { 279 thread_lock(td); 280 if (TD_ON_LOCK(td)) 281 deadlres_td_on_lock(p, td, 282 blkticks); 283 else if (TD_IS_SLEEPING(td)) 284 deadlres_td_sleep_q(p, td, 285 slpticks); 286 thread_unlock(td); 287 } 288 PROC_UNLOCK(p); 289 } 290 sx_sunlock(&allproc_lock); 291 292 /* Sleep for sleepfreq seconds. */ 293 pause("-", sleepfreq * hz); 294 } 295 } 296 297 static struct kthread_desc deadlkres_kd = { 298 "deadlkres", 299 deadlkres, 300 (struct thread **)NULL 301 }; 302 303 SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd); 304 305 static SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 306 "Deadlock resolver"); 307 SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW, 308 &slptime_threshold, 0, 309 "Number of seconds within is valid to sleep on a sleepqueue"); 310 SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW, 311 &blktime_threshold, 0, 312 "Number of seconds within is valid to block on a turnstile"); 313 SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0, 314 "Number of seconds between any deadlock resolver thread run"); 315 #endif /* DEADLKRES */ 316 317 void 318 read_cpu_time(long *cp_time) 319 { 320 struct pcpu *pc; 321 int i, j; 322 323 /* Sum up global cp_time[]. */ 324 bzero(cp_time, sizeof(long) * CPUSTATES); 325 CPU_FOREACH(i) { 326 pc = pcpu_find(i); 327 for (j = 0; j < CPUSTATES; j++) 328 cp_time[j] += pc->pc_cp_time[j]; 329 } 330 } 331 332 #include <sys/watchdog.h> 333 334 static int watchdog_ticks; 335 static int watchdog_enabled; 336 static void watchdog_fire(void); 337 static void watchdog_config(void *, u_int, int *); 338 339 static void 340 watchdog_attach(void) 341 { 342 EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0); 343 } 344 345 /* 346 * Clock handling routines. 347 * 348 * This code is written to operate with two timers that run independently of 349 * each other. 350 * 351 * The main timer, running hz times per second, is used to trigger interval 352 * timers, timeouts and rescheduling as needed. 353 * 354 * The second timer handles kernel and user profiling, 355 * and does resource use estimation. If the second timer is programmable, 356 * it is randomized to avoid aliasing between the two clocks. For example, 357 * the randomization prevents an adversary from always giving up the cpu 358 * just before its quantum expires. Otherwise, it would never accumulate 359 * cpu ticks. The mean frequency of the second timer is stathz. 360 * 361 * If no second timer exists, stathz will be zero; in this case we drive 362 * profiling and statistics off the main clock. This WILL NOT be accurate; 363 * do not do it unless absolutely necessary. 364 * 365 * The statistics clock may (or may not) be run at a higher rate while 366 * profiling. This profile clock runs at profhz. We require that profhz 367 * be an integral multiple of stathz. 368 * 369 * If the statistics clock is running fast, it must be divided by the ratio 370 * profhz/stathz for statistics. (For profiling, every tick counts.) 371 * 372 * Time-of-day is maintained using a "timecounter", which may or may 373 * not be related to the hardware generating the above mentioned 374 * interrupts. 375 */ 376 377 int stathz; 378 int profhz; 379 int profprocs; 380 volatile int ticks; 381 int psratio; 382 383 DPCPU_DEFINE_STATIC(int, pcputicks); /* Per-CPU version of ticks. */ 384 #ifdef DEVICE_POLLING 385 static int devpoll_run = 0; 386 #endif 387 388 /* 389 * Initialize clock frequencies and start both clocks running. 390 */ 391 static void 392 initclocks(void *dummy __unused) 393 { 394 int i; 395 396 /* 397 * Set divisors to 1 (normal case) and let the machine-specific 398 * code do its bit. 399 */ 400 mtx_init(&time_lock, "time lock", NULL, MTX_DEF); 401 cpu_initclocks(); 402 403 /* 404 * Compute profhz/stathz, and fix profhz if needed. 405 */ 406 i = stathz ? stathz : hz; 407 if (profhz == 0) 408 profhz = i; 409 psratio = profhz / i; 410 411 #ifdef SW_WATCHDOG 412 /* Enable hardclock watchdog now, even if a hardware watchdog exists. */ 413 watchdog_attach(); 414 #else 415 /* Volunteer to run a software watchdog. */ 416 if (wdog_software_attach == NULL) 417 wdog_software_attach = watchdog_attach; 418 #endif 419 } 420 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL); 421 422 static __noinline void 423 hardclock_itimer(struct thread *td, struct pstats *pstats, int cnt, int usermode) 424 { 425 struct proc *p; 426 int flags; 427 428 flags = 0; 429 p = td->td_proc; 430 if (usermode && 431 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) { 432 PROC_ITIMLOCK(p); 433 if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], 434 tick * cnt) == 0) 435 flags |= TDF_ALRMPEND | TDF_ASTPENDING; 436 PROC_ITIMUNLOCK(p); 437 } 438 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) { 439 PROC_ITIMLOCK(p); 440 if (itimerdecr(&pstats->p_timer[ITIMER_PROF], 441 tick * cnt) == 0) 442 flags |= TDF_PROFPEND | TDF_ASTPENDING; 443 PROC_ITIMUNLOCK(p); 444 } 445 if (flags != 0) { 446 thread_lock(td); 447 td->td_flags |= flags; 448 thread_unlock(td); 449 } 450 } 451 452 void 453 hardclock(int cnt, int usermode) 454 { 455 struct pstats *pstats; 456 struct thread *td = curthread; 457 struct proc *p = td->td_proc; 458 int *t = DPCPU_PTR(pcputicks); 459 int global, i, newticks; 460 461 /* 462 * Update per-CPU and possibly global ticks values. 463 */ 464 *t += cnt; 465 global = ticks; 466 do { 467 newticks = *t - global; 468 if (newticks <= 0) { 469 if (newticks < -1) 470 *t = global - 1; 471 newticks = 0; 472 break; 473 } 474 } while (!atomic_fcmpset_int(&ticks, &global, *t)); 475 476 /* 477 * Run current process's virtual and profile time, as needed. 478 */ 479 pstats = p->p_stats; 480 if (__predict_false( 481 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) || 482 timevalisset(&pstats->p_timer[ITIMER_PROF].it_value))) 483 hardclock_itimer(td, pstats, cnt, usermode); 484 485 #ifdef HWPMC_HOOKS 486 if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid))) 487 PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL); 488 if (td->td_intr_frame != NULL) 489 PMC_SOFT_CALL_TF( , , clock, hard, td->td_intr_frame); 490 #endif 491 /* We are in charge to handle this tick duty. */ 492 if (newticks > 0) { 493 tc_ticktock(newticks); 494 #ifdef DEVICE_POLLING 495 /* Dangerous and no need to call these things concurrently. */ 496 if (atomic_cmpset_acq_int(&devpoll_run, 0, 1)) { 497 /* This is very short and quick. */ 498 hardclock_device_poll(); 499 atomic_store_rel_int(&devpoll_run, 0); 500 } 501 #endif /* DEVICE_POLLING */ 502 if (watchdog_enabled > 0) { 503 i = atomic_fetchadd_int(&watchdog_ticks, -newticks); 504 if (i > 0 && i <= newticks) 505 watchdog_fire(); 506 } 507 intr_event_handle(clk_intr_event, NULL); 508 } 509 if (curcpu == CPU_FIRST()) 510 cpu_tick_calibration(); 511 if (__predict_false(DPCPU_GET(epoch_cb_count))) 512 GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task)); 513 } 514 515 void 516 hardclock_sync(int cpu) 517 { 518 int *t; 519 KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu)); 520 t = DPCPU_ID_PTR(cpu, pcputicks); 521 522 *t = ticks; 523 } 524 525 /* 526 * Regular integer scaling formula without losing precision: 527 */ 528 #define TIME_INT_SCALE(value, mul, div) \ 529 (((value) / (div)) * (mul) + (((value) % (div)) * (mul)) / (div)) 530 531 /* 532 * Macro for converting seconds and microseconds into actual ticks, 533 * based on the given hz value: 534 */ 535 #define TIME_TO_TICKS(sec, usec, hz) \ 536 ((sec) * (hz) + TIME_INT_SCALE(usec, hz, 1 << 6) / (1000000 >> 6)) 537 538 #define TIME_ASSERT_VALID_HZ(hz) \ 539 _Static_assert(TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) >= 0 && \ 540 TIME_TO_TICKS(INT_MAX / (hz) - 1, 999999, hz) < INT_MAX, \ 541 "tvtohz() can overflow the regular integer type") 542 543 /* 544 * Compile time assert the maximum and minimum values to fit into a 545 * regular integer when computing TIME_TO_TICKS(): 546 */ 547 TIME_ASSERT_VALID_HZ(HZ_MAXIMUM); 548 TIME_ASSERT_VALID_HZ(HZ_MINIMUM); 549 550 /* 551 * The formula is mostly linear, but test some more common values just 552 * in case: 553 */ 554 TIME_ASSERT_VALID_HZ(1024); 555 TIME_ASSERT_VALID_HZ(1000); 556 TIME_ASSERT_VALID_HZ(128); 557 TIME_ASSERT_VALID_HZ(100); 558 559 /* 560 * Compute number of ticks representing the specified amount of time. 561 * If the specified time is negative, a value of 1 is returned. This 562 * function returns a value from 1 up to and including INT_MAX. 563 */ 564 int 565 tvtohz(struct timeval *tv) 566 { 567 int retval; 568 569 /* 570 * The values passed here may come from user-space and these 571 * checks ensure "tv_usec" is within its allowed range: 572 */ 573 574 /* check for tv_usec underflow */ 575 if (__predict_false(tv->tv_usec < 0)) { 576 tv->tv_sec += tv->tv_usec / 1000000; 577 tv->tv_usec = tv->tv_usec % 1000000; 578 /* convert tv_usec to a positive value */ 579 if (__predict_true(tv->tv_usec < 0)) { 580 tv->tv_usec += 1000000; 581 tv->tv_sec -= 1; 582 } 583 /* check for tv_usec overflow */ 584 } else if (__predict_false(tv->tv_usec >= 1000000)) { 585 tv->tv_sec += tv->tv_usec / 1000000; 586 tv->tv_usec = tv->tv_usec % 1000000; 587 } 588 589 /* check for tv_sec underflow */ 590 if (__predict_false(tv->tv_sec < 0)) 591 return (1); 592 /* check for tv_sec overflow (including room for the tv_usec part) */ 593 else if (__predict_false(tv->tv_sec >= tick_seconds_max)) 594 return (INT_MAX); 595 596 /* cast to "int" to avoid platform differences */ 597 retval = TIME_TO_TICKS((int)tv->tv_sec, (int)tv->tv_usec, hz); 598 599 /* add one additional tick */ 600 return (retval + 1); 601 } 602 603 /* 604 * Start profiling on a process. 605 * 606 * Kernel profiling passes proc0 which never exits and hence 607 * keeps the profile clock running constantly. 608 */ 609 void 610 startprofclock(struct proc *p) 611 { 612 613 PROC_LOCK_ASSERT(p, MA_OWNED); 614 if (p->p_flag & P_STOPPROF) 615 return; 616 if ((p->p_flag & P_PROFIL) == 0) { 617 p->p_flag |= P_PROFIL; 618 mtx_lock(&time_lock); 619 if (++profprocs == 1) 620 cpu_startprofclock(); 621 mtx_unlock(&time_lock); 622 } 623 } 624 625 /* 626 * Stop profiling on a process. 627 */ 628 void 629 stopprofclock(struct proc *p) 630 { 631 632 PROC_LOCK_ASSERT(p, MA_OWNED); 633 if (p->p_flag & P_PROFIL) { 634 if (p->p_profthreads != 0) { 635 while (p->p_profthreads != 0) { 636 p->p_flag |= P_STOPPROF; 637 msleep(&p->p_profthreads, &p->p_mtx, PPAUSE, 638 "stopprof", 0); 639 } 640 } 641 if ((p->p_flag & P_PROFIL) == 0) 642 return; 643 p->p_flag &= ~P_PROFIL; 644 mtx_lock(&time_lock); 645 if (--profprocs == 0) 646 cpu_stopprofclock(); 647 mtx_unlock(&time_lock); 648 } 649 } 650 651 /* 652 * Statistics clock. Updates rusage information and calls the scheduler 653 * to adjust priorities of the active thread. 654 * 655 * This should be called by all active processors. 656 */ 657 void 658 statclock(int cnt, int usermode) 659 { 660 struct rusage *ru; 661 struct vmspace *vm; 662 struct thread *td; 663 struct proc *p; 664 long rss; 665 long *cp_time; 666 uint64_t runtime, new_switchtime; 667 668 td = curthread; 669 p = td->td_proc; 670 671 cp_time = (long *)PCPU_PTR(cp_time); 672 if (usermode) { 673 /* 674 * Charge the time as appropriate. 675 */ 676 td->td_uticks += cnt; 677 if (p->p_nice > NZERO) 678 cp_time[CP_NICE] += cnt; 679 else 680 cp_time[CP_USER] += cnt; 681 } else { 682 /* 683 * Came from kernel mode, so we were: 684 * - handling an interrupt, 685 * - doing syscall or trap work on behalf of the current 686 * user process, or 687 * - spinning in the idle loop. 688 * Whichever it is, charge the time as appropriate. 689 * Note that we charge interrupts to the current process, 690 * regardless of whether they are ``for'' that process, 691 * so that we know how much of its real time was spent 692 * in ``non-process'' (i.e., interrupt) work. 693 */ 694 if ((td->td_pflags & TDP_ITHREAD) || 695 td->td_intr_nesting_level >= 2) { 696 td->td_iticks += cnt; 697 cp_time[CP_INTR] += cnt; 698 } else { 699 td->td_pticks += cnt; 700 td->td_sticks += cnt; 701 if (!TD_IS_IDLETHREAD(td)) 702 cp_time[CP_SYS] += cnt; 703 else 704 cp_time[CP_IDLE] += cnt; 705 } 706 } 707 708 /* Update resource usage integrals and maximums. */ 709 MPASS(p->p_vmspace != NULL); 710 vm = p->p_vmspace; 711 ru = &td->td_ru; 712 ru->ru_ixrss += pgtok(vm->vm_tsize) * cnt; 713 ru->ru_idrss += pgtok(vm->vm_dsize) * cnt; 714 ru->ru_isrss += pgtok(vm->vm_ssize) * cnt; 715 rss = pgtok(vmspace_resident_count(vm)); 716 if (ru->ru_maxrss < rss) 717 ru->ru_maxrss = rss; 718 KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock", 719 "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz); 720 SDT_PROBE2(sched, , , tick, td, td->td_proc); 721 thread_lock_flags(td, MTX_QUIET); 722 723 /* 724 * Compute the amount of time during which the current 725 * thread was running, and add that to its total so far. 726 */ 727 new_switchtime = cpu_ticks(); 728 runtime = new_switchtime - PCPU_GET(switchtime); 729 td->td_runtime += runtime; 730 td->td_incruntime += runtime; 731 PCPU_SET(switchtime, new_switchtime); 732 733 sched_clock(td, cnt); 734 thread_unlock(td); 735 #ifdef HWPMC_HOOKS 736 if (td->td_intr_frame != NULL) 737 PMC_SOFT_CALL_TF( , , clock, stat, td->td_intr_frame); 738 #endif 739 } 740 741 void 742 profclock(int cnt, int usermode, uintfptr_t pc) 743 { 744 struct thread *td; 745 #ifdef GPROF 746 struct gmonparam *g; 747 uintfptr_t i; 748 #endif 749 750 td = curthread; 751 if (usermode) { 752 /* 753 * Came from user mode; CPU was in user state. 754 * If this process is being profiled, record the tick. 755 * if there is no related user location yet, don't 756 * bother trying to count it. 757 */ 758 if (td->td_proc->p_flag & P_PROFIL) 759 addupc_intr(td, pc, cnt); 760 } 761 #ifdef GPROF 762 else { 763 /* 764 * Kernel statistics are just like addupc_intr, only easier. 765 */ 766 g = &_gmonparam; 767 if (g->state == GMON_PROF_ON && pc >= g->lowpc) { 768 i = PC_TO_I(g, pc); 769 if (i < g->textsize) { 770 KCOUNT(g, i) += cnt; 771 } 772 } 773 } 774 #endif 775 #ifdef HWPMC_HOOKS 776 if (td->td_intr_frame != NULL) 777 PMC_SOFT_CALL_TF( , , clock, prof, td->td_intr_frame); 778 #endif 779 } 780 781 /* 782 * Return information about system clocks. 783 */ 784 static int 785 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS) 786 { 787 struct clockinfo clkinfo; 788 /* 789 * Construct clockinfo structure. 790 */ 791 bzero(&clkinfo, sizeof(clkinfo)); 792 clkinfo.hz = hz; 793 clkinfo.tick = tick; 794 clkinfo.profhz = profhz; 795 clkinfo.stathz = stathz ? stathz : hz; 796 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req)); 797 } 798 799 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, 800 CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE, 801 0, 0, sysctl_kern_clockrate, "S,clockinfo", 802 "Rate and period of various kernel clocks"); 803 804 static void 805 watchdog_config(void *unused __unused, u_int cmd, int *error) 806 { 807 u_int u; 808 809 u = cmd & WD_INTERVAL; 810 if (u >= WD_TO_1SEC) { 811 watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz; 812 watchdog_enabled = 1; 813 *error = 0; 814 } else { 815 watchdog_enabled = 0; 816 } 817 } 818 819 /* 820 * Handle a watchdog timeout by dumping interrupt information and 821 * then either dropping to DDB or panicking. 822 */ 823 static void 824 watchdog_fire(void) 825 { 826 int nintr; 827 uint64_t inttotal; 828 u_long *curintr; 829 char *curname; 830 831 curintr = intrcnt; 832 curname = intrnames; 833 inttotal = 0; 834 nintr = sintrcnt / sizeof(u_long); 835 836 printf("interrupt total\n"); 837 while (--nintr >= 0) { 838 if (*curintr) 839 printf("%-12s %20lu\n", curname, *curintr); 840 curname += strlen(curname) + 1; 841 inttotal += *curintr++; 842 } 843 printf("Total %20ju\n", (uintmax_t)inttotal); 844 845 #if defined(KDB) && !defined(KDB_UNATTENDED) 846 kdb_backtrace(); 847 kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout"); 848 #else 849 panic("watchdog timeout"); 850 #endif 851 }
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