xref: /freebsd/sys/kern/kern_clock.c (revision bdafb02fcb88389fd1ab684cfe734cb429d35618)
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/gtaskqueue.h>
53 #include <sys/kdb.h>
54 #include <sys/kernel.h>
55 #include <sys/kthread.h>
56 #include <sys/ktr.h>
57 #include <sys/lock.h>
58 #include <sys/mutex.h>
59 #include <sys/proc.h>
60 #include <sys/resource.h>
61 #include <sys/resourcevar.h>
62 #include <sys/sched.h>
63 #include <sys/sdt.h>
64 #include <sys/signalvar.h>
65 #include <sys/sleepqueue.h>
66 #include <sys/smp.h>
67 #include <vm/vm.h>
68 #include <vm/pmap.h>
69 #include <vm/vm_map.h>
70 #include <sys/sysctl.h>
71 #include <sys/bus.h>
72 #include <sys/interrupt.h>
73 #include <sys/limits.h>
74 #include <sys/timetc.h>
75 
76 #ifdef GPROF
77 #include <sys/gmon.h>
78 #endif
79 
80 #ifdef HWPMC_HOOKS
81 #include <sys/pmckern.h>
82 PMC_SOFT_DEFINE( , , clock, hard);
83 PMC_SOFT_DEFINE( , , clock, stat);
84 PMC_SOFT_DEFINE_EX( , , clock, prof, \
85     cpu_startprofclock, cpu_stopprofclock);
86 #endif
87 
88 #ifdef DEVICE_POLLING
89 extern void hardclock_device_poll(void);
90 #endif /* DEVICE_POLLING */
91 
92 static void initclocks(void *dummy);
93 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL);
94 
95 /* Spin-lock protecting profiling statistics. */
96 static struct mtx time_lock;
97 
98 SDT_PROVIDER_DECLARE(sched);
99 SDT_PROBE_DEFINE2(sched, , , tick, "struct thread *", "struct proc *");
100 
101 static int
102 sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS)
103 {
104 	int error;
105 	long cp_time[CPUSTATES];
106 #ifdef SCTL_MASK32
107 	int i;
108 	unsigned int cp_time32[CPUSTATES];
109 #endif
110 
111 	read_cpu_time(cp_time);
112 #ifdef SCTL_MASK32
113 	if (req->flags & SCTL_MASK32) {
114 		if (!req->oldptr)
115 			return SYSCTL_OUT(req, 0, sizeof(cp_time32));
116 		for (i = 0; i < CPUSTATES; i++)
117 			cp_time32[i] = (unsigned int)cp_time[i];
118 		error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
119 	} else
120 #endif
121 	{
122 		if (!req->oldptr)
123 			return SYSCTL_OUT(req, 0, sizeof(cp_time));
124 		error = SYSCTL_OUT(req, cp_time, sizeof(cp_time));
125 	}
126 	return error;
127 }
128 
129 SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
130     0,0, sysctl_kern_cp_time, "LU", "CPU time statistics");
131 
132 static long empty[CPUSTATES];
133 
134 static int
135 sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS)
136 {
137 	struct pcpu *pcpu;
138 	int error;
139 	int c;
140 	long *cp_time;
141 #ifdef SCTL_MASK32
142 	unsigned int cp_time32[CPUSTATES];
143 	int i;
144 #endif
145 
146 	if (!req->oldptr) {
147 #ifdef SCTL_MASK32
148 		if (req->flags & SCTL_MASK32)
149 			return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1));
150 		else
151 #endif
152 			return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1));
153 	}
154 	for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) {
155 		if (!CPU_ABSENT(c)) {
156 			pcpu = pcpu_find(c);
157 			cp_time = pcpu->pc_cp_time;
158 		} else {
159 			cp_time = empty;
160 		}
161 #ifdef SCTL_MASK32
162 		if (req->flags & SCTL_MASK32) {
163 			for (i = 0; i < CPUSTATES; i++)
164 				cp_time32[i] = (unsigned int)cp_time[i];
165 			error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
166 		} else
167 #endif
168 			error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES);
169 	}
170 	return error;
171 }
172 
173 SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
174     0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics");
175 
176 #ifdef DEADLKRES
177 static const char *blessed[] = {
178 	"getblk",
179 	"so_snd_sx",
180 	"so_rcv_sx",
181 	NULL
182 };
183 static int slptime_threshold = 1800;
184 static int blktime_threshold = 900;
185 static int sleepfreq = 3;
186 
187 static void
188 deadlres_td_on_lock(struct proc *p, struct thread *td, int blkticks)
189 {
190 	int tticks;
191 
192 	sx_assert(&allproc_lock, SX_LOCKED);
193 	PROC_LOCK_ASSERT(p, MA_OWNED);
194 	THREAD_LOCK_ASSERT(td, MA_OWNED);
195 	/*
196 	 * The thread should be blocked on a turnstile, simply check
197 	 * if the turnstile channel is in good state.
198 	 */
199 	MPASS(td->td_blocked != NULL);
200 
201 	tticks = ticks - td->td_blktick;
202 	if (tticks > blkticks)
203 		/*
204 		 * Accordingly with provided thresholds, this thread is stuck
205 		 * for too long on a turnstile.
206 		 */
207 		panic("%s: possible deadlock detected for %p, "
208 		    "blocked for %d ticks\n", __func__, td, tticks);
209 }
210 
211 static void
212 deadlres_td_sleep_q(struct proc *p, struct thread *td, int slpticks)
213 {
214 	void *wchan;
215 	int i, slptype, tticks;
216 
217 	sx_assert(&allproc_lock, SX_LOCKED);
218 	PROC_LOCK_ASSERT(p, MA_OWNED);
219 	THREAD_LOCK_ASSERT(td, MA_OWNED);
220 	/*
221 	 * Check if the thread is sleeping on a lock, otherwise skip the check.
222 	 * Drop the thread lock in order to avoid a LOR with the sleepqueue
223 	 * spinlock.
224 	 */
225 	wchan = td->td_wchan;
226 	tticks = ticks - td->td_slptick;
227 	slptype = sleepq_type(wchan);
228 	if ((slptype == SLEEPQ_SX || slptype == SLEEPQ_LK) &&
229 	    tticks > slpticks) {
230 
231 		/*
232 		 * Accordingly with provided thresholds, this thread is stuck
233 		 * for too long on a sleepqueue.
234 		 * However, being on a sleepqueue, we might still check for the
235 		 * blessed list.
236 		 */
237 		for (i = 0; blessed[i] != NULL; i++)
238 			if (!strcmp(blessed[i], td->td_wmesg))
239 				return;
240 
241 		panic("%s: possible deadlock detected for %p, "
242 		    "blocked for %d ticks\n", __func__, td, tticks);
243 	}
244 }
245 
246 static void
247 deadlkres(void)
248 {
249 	struct proc *p;
250 	struct thread *td;
251 	int blkticks, slpticks, tryl;
252 
253 	tryl = 0;
254 	for (;;) {
255 		blkticks = blktime_threshold * hz;
256 		slpticks = slptime_threshold * hz;
257 
258 		/*
259 		 * Avoid to sleep on the sx_lock in order to avoid a
260 		 * possible priority inversion problem leading to
261 		 * starvation.
262 		 * If the lock can't be held after 100 tries, panic.
263 		 */
264 		if (!sx_try_slock(&allproc_lock)) {
265 			if (tryl > 100)
266 				panic("%s: possible deadlock detected "
267 				    "on allproc_lock\n", __func__);
268 			tryl++;
269 			pause("allproc", sleepfreq * hz);
270 			continue;
271 		}
272 		tryl = 0;
273 		FOREACH_PROC_IN_SYSTEM(p) {
274 			PROC_LOCK(p);
275 			if (p->p_state == PRS_NEW) {
276 				PROC_UNLOCK(p);
277 				continue;
278 			}
279 			FOREACH_THREAD_IN_PROC(p, td) {
280 				thread_lock(td);
281 				if (TD_ON_LOCK(td))
282 					deadlres_td_on_lock(p, td,
283 					    blkticks);
284 				else if (TD_IS_SLEEPING(td) &&
285 				    TD_ON_SLEEPQ(td))
286 					deadlres_td_sleep_q(p, td,
287 					    slpticks);
288 				thread_unlock(td);
289 			}
290 			PROC_UNLOCK(p);
291 		}
292 		sx_sunlock(&allproc_lock);
293 
294 		/* Sleep for sleepfreq seconds. */
295 		pause("-", sleepfreq * hz);
296 	}
297 }
298 
299 static struct kthread_desc deadlkres_kd = {
300 	"deadlkres",
301 	deadlkres,
302 	(struct thread **)NULL
303 };
304 
305 SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd);
306 
307 static SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW, 0,
308     "Deadlock resolver");
309 SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW,
310     &slptime_threshold, 0,
311     "Number of seconds within is valid to sleep on a sleepqueue");
312 SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW,
313     &blktime_threshold, 0,
314     "Number of seconds within is valid to block on a turnstile");
315 SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0,
316     "Number of seconds between any deadlock resolver thread run");
317 #endif	/* DEADLKRES */
318 
319 void
320 read_cpu_time(long *cp_time)
321 {
322 	struct pcpu *pc;
323 	int i, j;
324 
325 	/* Sum up global cp_time[]. */
326 	bzero(cp_time, sizeof(long) * CPUSTATES);
327 	CPU_FOREACH(i) {
328 		pc = pcpu_find(i);
329 		for (j = 0; j < CPUSTATES; j++)
330 			cp_time[j] += pc->pc_cp_time[j];
331 	}
332 }
333 
334 #include <sys/watchdog.h>
335 
336 static int watchdog_ticks;
337 static int watchdog_enabled;
338 static void watchdog_fire(void);
339 static void watchdog_config(void *, u_int, int *);
340 
341 static void
342 watchdog_attach(void)
343 {
344 	EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
345 }
346 
347 /*
348  * Clock handling routines.
349  *
350  * This code is written to operate with two timers that run independently of
351  * each other.
352  *
353  * The main timer, running hz times per second, is used to trigger interval
354  * timers, timeouts and rescheduling as needed.
355  *
356  * The second timer handles kernel and user profiling,
357  * and does resource use estimation.  If the second timer is programmable,
358  * it is randomized to avoid aliasing between the two clocks.  For example,
359  * the randomization prevents an adversary from always giving up the cpu
360  * just before its quantum expires.  Otherwise, it would never accumulate
361  * cpu ticks.  The mean frequency of the second timer is stathz.
362  *
363  * If no second timer exists, stathz will be zero; in this case we drive
364  * profiling and statistics off the main clock.  This WILL NOT be accurate;
365  * do not do it unless absolutely necessary.
366  *
367  * The statistics clock may (or may not) be run at a higher rate while
368  * profiling.  This profile clock runs at profhz.  We require that profhz
369  * be an integral multiple of stathz.
370  *
371  * If the statistics clock is running fast, it must be divided by the ratio
372  * profhz/stathz for statistics.  (For profiling, every tick counts.)
373  *
374  * Time-of-day is maintained using a "timecounter", which may or may
375  * not be related to the hardware generating the above mentioned
376  * interrupts.
377  */
378 
379 int	stathz;
380 int	profhz;
381 int	profprocs;
382 volatile int	ticks;
383 int	psratio;
384 
385 DPCPU_DEFINE_STATIC(int, pcputicks);	/* Per-CPU version of ticks. */
386 #ifdef DEVICE_POLLING
387 static int devpoll_run = 0;
388 #endif
389 
390 /*
391  * Initialize clock frequencies and start both clocks running.
392  */
393 /* ARGSUSED*/
394 static void
395 initclocks(void *dummy)
396 {
397 	int i;
398 
399 	/*
400 	 * Set divisors to 1 (normal case) and let the machine-specific
401 	 * code do its bit.
402 	 */
403 	mtx_init(&time_lock, "time lock", NULL, MTX_DEF);
404 	cpu_initclocks();
405 
406 	/*
407 	 * Compute profhz/stathz, and fix profhz if needed.
408 	 */
409 	i = stathz ? stathz : hz;
410 	if (profhz == 0)
411 		profhz = i;
412 	psratio = profhz / i;
413 
414 #ifdef SW_WATCHDOG
415 	/* Enable hardclock watchdog now, even if a hardware watchdog exists. */
416 	watchdog_attach();
417 #else
418 	/* Volunteer to run a software watchdog. */
419 	if (wdog_software_attach == NULL)
420 		wdog_software_attach = watchdog_attach;
421 #endif
422 }
423 
424 void
425 hardclock(int cnt, int usermode)
426 {
427 	struct pstats *pstats;
428 	struct thread *td = curthread;
429 	struct proc *p = td->td_proc;
430 	int *t = DPCPU_PTR(pcputicks);
431 	int flags, global, newticks;
432 	int i;
433 
434 	/*
435 	 * Update per-CPU and possibly global ticks values.
436 	 */
437 	*t += cnt;
438 	do {
439 		global = ticks;
440 		newticks = *t - global;
441 		if (newticks <= 0) {
442 			if (newticks < -1)
443 				*t = global - 1;
444 			newticks = 0;
445 			break;
446 		}
447 	} while (!atomic_cmpset_int(&ticks, global, *t));
448 
449 	/*
450 	 * Run current process's virtual and profile time, as needed.
451 	 */
452 	pstats = p->p_stats;
453 	flags = 0;
454 	if (usermode &&
455 	    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) {
456 		PROC_ITIMLOCK(p);
457 		if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL],
458 		    tick * cnt) == 0)
459 			flags |= TDF_ALRMPEND | TDF_ASTPENDING;
460 		PROC_ITIMUNLOCK(p);
461 	}
462 	if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) {
463 		PROC_ITIMLOCK(p);
464 		if (itimerdecr(&pstats->p_timer[ITIMER_PROF],
465 		    tick * cnt) == 0)
466 			flags |= TDF_PROFPEND | TDF_ASTPENDING;
467 		PROC_ITIMUNLOCK(p);
468 	}
469 	if (flags != 0) {
470 		thread_lock(td);
471 		td->td_flags |= flags;
472 		thread_unlock(td);
473 	}
474 
475 #ifdef	HWPMC_HOOKS
476 	if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
477 		PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
478 	if (td->td_intr_frame != NULL)
479 		PMC_SOFT_CALL_TF( , , clock, hard, td->td_intr_frame);
480 #endif
481 	/* We are in charge to handle this tick duty. */
482 	if (newticks > 0) {
483 		tc_ticktock(newticks);
484 #ifdef DEVICE_POLLING
485 		/* Dangerous and no need to call these things concurrently. */
486 		if (atomic_cmpset_acq_int(&devpoll_run, 0, 1)) {
487 			/* This is very short and quick. */
488 			hardclock_device_poll();
489 			atomic_store_rel_int(&devpoll_run, 0);
490 		}
491 #endif /* DEVICE_POLLING */
492 		if (watchdog_enabled > 0) {
493 			i = atomic_fetchadd_int(&watchdog_ticks, -newticks);
494 			if (i > 0 && i <= newticks)
495 				watchdog_fire();
496 		}
497 	}
498 	if (curcpu == CPU_FIRST())
499 		cpu_tick_calibration();
500 	if (__predict_false(DPCPU_GET(epoch_cb_count)))
501 		GROUPTASK_ENQUEUE(DPCPU_PTR(epoch_cb_task));
502 }
503 
504 void
505 hardclock_sync(int cpu)
506 {
507 	int *t;
508 	KASSERT(!CPU_ABSENT(cpu), ("Absent CPU %d", cpu));
509 	t = DPCPU_ID_PTR(cpu, pcputicks);
510 
511 	*t = ticks;
512 }
513 
514 /*
515  * Compute number of ticks in the specified amount of time.
516  */
517 int
518 tvtohz(struct timeval *tv)
519 {
520 	unsigned long ticks;
521 	long sec, usec;
522 
523 	/*
524 	 * If the number of usecs in the whole seconds part of the time
525 	 * difference fits in a long, then the total number of usecs will
526 	 * fit in an unsigned long.  Compute the total and convert it to
527 	 * ticks, rounding up and adding 1 to allow for the current tick
528 	 * to expire.  Rounding also depends on unsigned long arithmetic
529 	 * to avoid overflow.
530 	 *
531 	 * Otherwise, if the number of ticks in the whole seconds part of
532 	 * the time difference fits in a long, then convert the parts to
533 	 * ticks separately and add, using similar rounding methods and
534 	 * overflow avoidance.  This method would work in the previous
535 	 * case but it is slightly slower and assumes that hz is integral.
536 	 *
537 	 * Otherwise, round the time difference down to the maximum
538 	 * representable value.
539 	 *
540 	 * If ints have 32 bits, then the maximum value for any timeout in
541 	 * 10ms ticks is 248 days.
542 	 */
543 	sec = tv->tv_sec;
544 	usec = tv->tv_usec;
545 	if (usec < 0) {
546 		sec--;
547 		usec += 1000000;
548 	}
549 	if (sec < 0) {
550 #ifdef DIAGNOSTIC
551 		if (usec > 0) {
552 			sec++;
553 			usec -= 1000000;
554 		}
555 		printf("tvotohz: negative time difference %ld sec %ld usec\n",
556 		       sec, usec);
557 #endif
558 		ticks = 1;
559 	} else if (sec <= LONG_MAX / 1000000)
560 		ticks = howmany(sec * 1000000 + (unsigned long)usec, tick) + 1;
561 	else if (sec <= LONG_MAX / hz)
562 		ticks = sec * hz
563 			+ howmany((unsigned long)usec, tick) + 1;
564 	else
565 		ticks = LONG_MAX;
566 	if (ticks > INT_MAX)
567 		ticks = INT_MAX;
568 	return ((int)ticks);
569 }
570 
571 /*
572  * Start profiling on a process.
573  *
574  * Kernel profiling passes proc0 which never exits and hence
575  * keeps the profile clock running constantly.
576  */
577 void
578 startprofclock(struct proc *p)
579 {
580 
581 	PROC_LOCK_ASSERT(p, MA_OWNED);
582 	if (p->p_flag & P_STOPPROF)
583 		return;
584 	if ((p->p_flag & P_PROFIL) == 0) {
585 		p->p_flag |= P_PROFIL;
586 		mtx_lock(&time_lock);
587 		if (++profprocs == 1)
588 			cpu_startprofclock();
589 		mtx_unlock(&time_lock);
590 	}
591 }
592 
593 /*
594  * Stop profiling on a process.
595  */
596 void
597 stopprofclock(struct proc *p)
598 {
599 
600 	PROC_LOCK_ASSERT(p, MA_OWNED);
601 	if (p->p_flag & P_PROFIL) {
602 		if (p->p_profthreads != 0) {
603 			while (p->p_profthreads != 0) {
604 				p->p_flag |= P_STOPPROF;
605 				msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
606 				    "stopprof", 0);
607 			}
608 		}
609 		if ((p->p_flag & P_PROFIL) == 0)
610 			return;
611 		p->p_flag &= ~P_PROFIL;
612 		mtx_lock(&time_lock);
613 		if (--profprocs == 0)
614 			cpu_stopprofclock();
615 		mtx_unlock(&time_lock);
616 	}
617 }
618 
619 /*
620  * Statistics clock.  Updates rusage information and calls the scheduler
621  * to adjust priorities of the active thread.
622  *
623  * This should be called by all active processors.
624  */
625 void
626 statclock(int cnt, int usermode)
627 {
628 	struct rusage *ru;
629 	struct vmspace *vm;
630 	struct thread *td;
631 	struct proc *p;
632 	long rss;
633 	long *cp_time;
634 
635 	td = curthread;
636 	p = td->td_proc;
637 
638 	cp_time = (long *)PCPU_PTR(cp_time);
639 	if (usermode) {
640 		/*
641 		 * Charge the time as appropriate.
642 		 */
643 		td->td_uticks += cnt;
644 		if (p->p_nice > NZERO)
645 			cp_time[CP_NICE] += cnt;
646 		else
647 			cp_time[CP_USER] += cnt;
648 	} else {
649 		/*
650 		 * Came from kernel mode, so we were:
651 		 * - handling an interrupt,
652 		 * - doing syscall or trap work on behalf of the current
653 		 *   user process, or
654 		 * - spinning in the idle loop.
655 		 * Whichever it is, charge the time as appropriate.
656 		 * Note that we charge interrupts to the current process,
657 		 * regardless of whether they are ``for'' that process,
658 		 * so that we know how much of its real time was spent
659 		 * in ``non-process'' (i.e., interrupt) work.
660 		 */
661 		if ((td->td_pflags & TDP_ITHREAD) ||
662 		    td->td_intr_nesting_level >= 2) {
663 			td->td_iticks += cnt;
664 			cp_time[CP_INTR] += cnt;
665 		} else {
666 			td->td_pticks += cnt;
667 			td->td_sticks += cnt;
668 			if (!TD_IS_IDLETHREAD(td))
669 				cp_time[CP_SYS] += cnt;
670 			else
671 				cp_time[CP_IDLE] += cnt;
672 		}
673 	}
674 
675 	/* Update resource usage integrals and maximums. */
676 	MPASS(p->p_vmspace != NULL);
677 	vm = p->p_vmspace;
678 	ru = &td->td_ru;
679 	ru->ru_ixrss += pgtok(vm->vm_tsize) * cnt;
680 	ru->ru_idrss += pgtok(vm->vm_dsize) * cnt;
681 	ru->ru_isrss += pgtok(vm->vm_ssize) * cnt;
682 	rss = pgtok(vmspace_resident_count(vm));
683 	if (ru->ru_maxrss < rss)
684 		ru->ru_maxrss = rss;
685 	KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock",
686 	    "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz);
687 	SDT_PROBE2(sched, , , tick, td, td->td_proc);
688 	thread_lock_flags(td, MTX_QUIET);
689 	for ( ; cnt > 0; cnt--)
690 		sched_clock(td);
691 	thread_unlock(td);
692 #ifdef HWPMC_HOOKS
693 	if (td->td_intr_frame != NULL)
694 		PMC_SOFT_CALL_TF( , , clock, stat, td->td_intr_frame);
695 #endif
696 }
697 
698 void
699 profclock(int cnt, int usermode, uintfptr_t pc)
700 {
701 	struct thread *td;
702 #ifdef GPROF
703 	struct gmonparam *g;
704 	uintfptr_t i;
705 #endif
706 
707 	td = curthread;
708 	if (usermode) {
709 		/*
710 		 * Came from user mode; CPU was in user state.
711 		 * If this process is being profiled, record the tick.
712 		 * if there is no related user location yet, don't
713 		 * bother trying to count it.
714 		 */
715 		if (td->td_proc->p_flag & P_PROFIL)
716 			addupc_intr(td, pc, cnt);
717 	}
718 #ifdef GPROF
719 	else {
720 		/*
721 		 * Kernel statistics are just like addupc_intr, only easier.
722 		 */
723 		g = &_gmonparam;
724 		if (g->state == GMON_PROF_ON && pc >= g->lowpc) {
725 			i = PC_TO_I(g, pc);
726 			if (i < g->textsize) {
727 				KCOUNT(g, i) += cnt;
728 			}
729 		}
730 	}
731 #endif
732 #ifdef HWPMC_HOOKS
733 	if (td->td_intr_frame != NULL)
734 		PMC_SOFT_CALL_TF( , , clock, prof, td->td_intr_frame);
735 #endif
736 }
737 
738 /*
739  * Return information about system clocks.
740  */
741 static int
742 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
743 {
744 	struct clockinfo clkinfo;
745 	/*
746 	 * Construct clockinfo structure.
747 	 */
748 	bzero(&clkinfo, sizeof(clkinfo));
749 	clkinfo.hz = hz;
750 	clkinfo.tick = tick;
751 	clkinfo.profhz = profhz;
752 	clkinfo.stathz = stathz ? stathz : hz;
753 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
754 }
755 
756 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate,
757 	CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE,
758 	0, 0, sysctl_kern_clockrate, "S,clockinfo",
759 	"Rate and period of various kernel clocks");
760 
761 static void
762 watchdog_config(void *unused __unused, u_int cmd, int *error)
763 {
764 	u_int u;
765 
766 	u = cmd & WD_INTERVAL;
767 	if (u >= WD_TO_1SEC) {
768 		watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
769 		watchdog_enabled = 1;
770 		*error = 0;
771 	} else {
772 		watchdog_enabled = 0;
773 	}
774 }
775 
776 /*
777  * Handle a watchdog timeout by dumping interrupt information and
778  * then either dropping to DDB or panicking.
779  */
780 static void
781 watchdog_fire(void)
782 {
783 	int nintr;
784 	uint64_t inttotal;
785 	u_long *curintr;
786 	char *curname;
787 
788 	curintr = intrcnt;
789 	curname = intrnames;
790 	inttotal = 0;
791 	nintr = sintrcnt / sizeof(u_long);
792 
793 	printf("interrupt                   total\n");
794 	while (--nintr >= 0) {
795 		if (*curintr)
796 			printf("%-12s %20lu\n", curname, *curintr);
797 		curname += strlen(curname) + 1;
798 		inttotal += *curintr++;
799 	}
800 	printf("Total        %20ju\n", (uintmax_t)inttotal);
801 
802 #if defined(KDB) && !defined(KDB_UNATTENDED)
803 	kdb_backtrace();
804 	kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
805 #else
806 	panic("watchdog timeout");
807 #endif
808 }
809