xref: /freebsd/sys/kern/kern_clock.c (revision aa0a1e58)
1 /*-
2  * Copyright (c) 1982, 1986, 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)kern_clock.c	8.5 (Berkeley) 1/21/94
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "opt_kdb.h"
41 #include "opt_device_polling.h"
42 #include "opt_hwpmc_hooks.h"
43 #include "opt_ntp.h"
44 #include "opt_watchdog.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/callout.h>
49 #include <sys/kdb.h>
50 #include <sys/kernel.h>
51 #include <sys/kthread.h>
52 #include <sys/ktr.h>
53 #include <sys/lock.h>
54 #include <sys/mutex.h>
55 #include <sys/proc.h>
56 #include <sys/resource.h>
57 #include <sys/resourcevar.h>
58 #include <sys/sched.h>
59 #include <sys/signalvar.h>
60 #include <sys/sleepqueue.h>
61 #include <sys/smp.h>
62 #include <vm/vm.h>
63 #include <vm/pmap.h>
64 #include <vm/vm_map.h>
65 #include <sys/sysctl.h>
66 #include <sys/bus.h>
67 #include <sys/interrupt.h>
68 #include <sys/limits.h>
69 #include <sys/timetc.h>
70 
71 #ifdef GPROF
72 #include <sys/gmon.h>
73 #endif
74 
75 #ifdef HWPMC_HOOKS
76 #include <sys/pmckern.h>
77 #endif
78 
79 #ifdef DEVICE_POLLING
80 extern void hardclock_device_poll(void);
81 #endif /* DEVICE_POLLING */
82 
83 static void initclocks(void *dummy);
84 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL);
85 
86 /* Spin-lock protecting profiling statistics. */
87 static struct mtx time_lock;
88 
89 static int
90 sysctl_kern_cp_time(SYSCTL_HANDLER_ARGS)
91 {
92 	int error;
93 	long cp_time[CPUSTATES];
94 #ifdef SCTL_MASK32
95 	int i;
96 	unsigned int cp_time32[CPUSTATES];
97 #endif
98 
99 	read_cpu_time(cp_time);
100 #ifdef SCTL_MASK32
101 	if (req->flags & SCTL_MASK32) {
102 		if (!req->oldptr)
103 			return SYSCTL_OUT(req, 0, sizeof(cp_time32));
104 		for (i = 0; i < CPUSTATES; i++)
105 			cp_time32[i] = (unsigned int)cp_time[i];
106 		error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
107 	} else
108 #endif
109 	{
110 		if (!req->oldptr)
111 			return SYSCTL_OUT(req, 0, sizeof(cp_time));
112 		error = SYSCTL_OUT(req, cp_time, sizeof(cp_time));
113 	}
114 	return error;
115 }
116 
117 SYSCTL_PROC(_kern, OID_AUTO, cp_time, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
118     0,0, sysctl_kern_cp_time, "LU", "CPU time statistics");
119 
120 static long empty[CPUSTATES];
121 
122 static int
123 sysctl_kern_cp_times(SYSCTL_HANDLER_ARGS)
124 {
125 	struct pcpu *pcpu;
126 	int error;
127 	int c;
128 	long *cp_time;
129 #ifdef SCTL_MASK32
130 	unsigned int cp_time32[CPUSTATES];
131 	int i;
132 #endif
133 
134 	if (!req->oldptr) {
135 #ifdef SCTL_MASK32
136 		if (req->flags & SCTL_MASK32)
137 			return SYSCTL_OUT(req, 0, sizeof(cp_time32) * (mp_maxid + 1));
138 		else
139 #endif
140 			return SYSCTL_OUT(req, 0, sizeof(long) * CPUSTATES * (mp_maxid + 1));
141 	}
142 	for (error = 0, c = 0; error == 0 && c <= mp_maxid; c++) {
143 		if (!CPU_ABSENT(c)) {
144 			pcpu = pcpu_find(c);
145 			cp_time = pcpu->pc_cp_time;
146 		} else {
147 			cp_time = empty;
148 		}
149 #ifdef SCTL_MASK32
150 		if (req->flags & SCTL_MASK32) {
151 			for (i = 0; i < CPUSTATES; i++)
152 				cp_time32[i] = (unsigned int)cp_time[i];
153 			error = SYSCTL_OUT(req, cp_time32, sizeof(cp_time32));
154 		} else
155 #endif
156 			error = SYSCTL_OUT(req, cp_time, sizeof(long) * CPUSTATES);
157 	}
158 	return error;
159 }
160 
161 SYSCTL_PROC(_kern, OID_AUTO, cp_times, CTLTYPE_LONG|CTLFLAG_RD|CTLFLAG_MPSAFE,
162     0,0, sysctl_kern_cp_times, "LU", "per-CPU time statistics");
163 
164 #ifdef DEADLKRES
165 static const char *blessed[] = {
166 	"getblk",
167 	"so_snd_sx",
168 	"so_rcv_sx",
169 	NULL
170 };
171 static int slptime_threshold = 1800;
172 static int blktime_threshold = 900;
173 static int sleepfreq = 3;
174 
175 static void
176 deadlkres(void)
177 {
178 	struct proc *p;
179 	struct thread *td;
180 	void *wchan;
181 	int blkticks, i, slpticks, slptype, tryl, tticks;
182 
183 	tryl = 0;
184 	for (;;) {
185 		blkticks = blktime_threshold * hz;
186 		slpticks = slptime_threshold * hz;
187 
188 		/*
189 		 * Avoid to sleep on the sx_lock in order to avoid a possible
190 		 * priority inversion problem leading to starvation.
191 		 * If the lock can't be held after 100 tries, panic.
192 		 */
193 		if (!sx_try_slock(&allproc_lock)) {
194 			if (tryl > 100)
195 		panic("%s: possible deadlock detected on allproc_lock\n",
196 				    __func__);
197 			tryl++;
198 			pause("allproc", sleepfreq * hz);
199 			continue;
200 		}
201 		tryl = 0;
202 		FOREACH_PROC_IN_SYSTEM(p) {
203 			PROC_LOCK(p);
204 			FOREACH_THREAD_IN_PROC(p, td) {
205 
206 				/*
207 				 * Once a thread is found in "interesting"
208 				 * state a possible ticks wrap-up needs to be
209 				 * checked.
210 				 */
211 				thread_lock(td);
212 				if (TD_ON_LOCK(td) && ticks < td->td_blktick) {
213 
214 					/*
215 					 * The thread should be blocked on a
216 					 * turnstile, simply check if the
217 					 * turnstile channel is in good state.
218 					 */
219 					MPASS(td->td_blocked != NULL);
220 
221 					tticks = ticks - td->td_blktick;
222 					thread_unlock(td);
223 					if (tticks > blkticks) {
224 
225 						/*
226 						 * Accordingly with provided
227 						 * thresholds, this thread is
228 						 * stuck for too long on a
229 						 * turnstile.
230 						 */
231 						PROC_UNLOCK(p);
232 						sx_sunlock(&allproc_lock);
233 	panic("%s: possible deadlock detected for %p, blocked for %d ticks\n",
234 						    __func__, td, tticks);
235 					}
236 				} else if (TD_IS_SLEEPING(td) &&
237 				    TD_ON_SLEEPQ(td) &&
238 				    ticks < td->td_blktick) {
239 
240 					/*
241 					 * Check if the thread is sleeping on a
242 					 * lock, otherwise skip the check.
243 					 * Drop the thread lock in order to
244 					 * avoid a LOR with the sleepqueue
245 					 * spinlock.
246 					 */
247 					wchan = td->td_wchan;
248 					tticks = ticks - td->td_slptick;
249 					thread_unlock(td);
250 					slptype = sleepq_type(wchan);
251 					if ((slptype == SLEEPQ_SX ||
252 					    slptype == SLEEPQ_LK) &&
253 					    tticks > slpticks) {
254 
255 						/*
256 						 * Accordingly with provided
257 						 * thresholds, this thread is
258 						 * stuck for too long on a
259 						 * sleepqueue.
260 						 * However, being on a
261 						 * sleepqueue, we might still
262 						 * check for the blessed
263 						 * list.
264 						 */
265 						tryl = 0;
266 						for (i = 0; blessed[i] != NULL;
267 						    i++) {
268 							if (!strcmp(blessed[i],
269 							    td->td_wmesg)) {
270 								tryl = 1;
271 								break;
272 							}
273 						}
274 						if (tryl != 0) {
275 							tryl = 0;
276 							continue;
277 						}
278 						PROC_UNLOCK(p);
279 						sx_sunlock(&allproc_lock);
280 	panic("%s: possible deadlock detected for %p, blocked for %d ticks\n",
281 						    __func__, td, tticks);
282 					}
283 				} else
284 					thread_unlock(td);
285 			}
286 			PROC_UNLOCK(p);
287 		}
288 		sx_sunlock(&allproc_lock);
289 
290 		/* Sleep for sleepfreq seconds. */
291 		pause("-", sleepfreq * hz);
292 	}
293 }
294 
295 static struct kthread_desc deadlkres_kd = {
296 	"deadlkres",
297 	deadlkres,
298 	(struct thread **)NULL
299 };
300 
301 SYSINIT(deadlkres, SI_SUB_CLOCKS, SI_ORDER_ANY, kthread_start, &deadlkres_kd);
302 
303 SYSCTL_NODE(_debug, OID_AUTO, deadlkres, CTLFLAG_RW, 0, "Deadlock resolver");
304 SYSCTL_INT(_debug_deadlkres, OID_AUTO, slptime_threshold, CTLFLAG_RW,
305     &slptime_threshold, 0,
306     "Number of seconds within is valid to sleep on a sleepqueue");
307 SYSCTL_INT(_debug_deadlkres, OID_AUTO, blktime_threshold, CTLFLAG_RW,
308     &blktime_threshold, 0,
309     "Number of seconds within is valid to block on a turnstile");
310 SYSCTL_INT(_debug_deadlkres, OID_AUTO, sleepfreq, CTLFLAG_RW, &sleepfreq, 0,
311     "Number of seconds between any deadlock resolver thread run");
312 #endif	/* DEADLKRES */
313 
314 void
315 read_cpu_time(long *cp_time)
316 {
317 	struct pcpu *pc;
318 	int i, j;
319 
320 	/* Sum up global cp_time[]. */
321 	bzero(cp_time, sizeof(long) * CPUSTATES);
322 	CPU_FOREACH(i) {
323 		pc = pcpu_find(i);
324 		for (j = 0; j < CPUSTATES; j++)
325 			cp_time[j] += pc->pc_cp_time[j];
326 	}
327 }
328 
329 #ifdef SW_WATCHDOG
330 #include <sys/watchdog.h>
331 
332 static int watchdog_ticks;
333 static int watchdog_enabled;
334 static void watchdog_fire(void);
335 static void watchdog_config(void *, u_int, int *);
336 #endif /* SW_WATCHDOG */
337 
338 /*
339  * Clock handling routines.
340  *
341  * This code is written to operate with two timers that run independently of
342  * each other.
343  *
344  * The main timer, running hz times per second, is used to trigger interval
345  * timers, timeouts and rescheduling as needed.
346  *
347  * The second timer handles kernel and user profiling,
348  * and does resource use estimation.  If the second timer is programmable,
349  * it is randomized to avoid aliasing between the two clocks.  For example,
350  * the randomization prevents an adversary from always giving up the cpu
351  * just before its quantum expires.  Otherwise, it would never accumulate
352  * cpu ticks.  The mean frequency of the second timer is stathz.
353  *
354  * If no second timer exists, stathz will be zero; in this case we drive
355  * profiling and statistics off the main clock.  This WILL NOT be accurate;
356  * do not do it unless absolutely necessary.
357  *
358  * The statistics clock may (or may not) be run at a higher rate while
359  * profiling.  This profile clock runs at profhz.  We require that profhz
360  * be an integral multiple of stathz.
361  *
362  * If the statistics clock is running fast, it must be divided by the ratio
363  * profhz/stathz for statistics.  (For profiling, every tick counts.)
364  *
365  * Time-of-day is maintained using a "timecounter", which may or may
366  * not be related to the hardware generating the above mentioned
367  * interrupts.
368  */
369 
370 int	stathz;
371 int	profhz;
372 int	profprocs;
373 int	ticks;
374 int	psratio;
375 
376 static DPCPU_DEFINE(int, pcputicks);	/* Per-CPU version of ticks. */
377 static int global_hardclock_run = 0;
378 
379 /*
380  * Initialize clock frequencies and start both clocks running.
381  */
382 /* ARGSUSED*/
383 static void
384 initclocks(dummy)
385 	void *dummy;
386 {
387 	register int i;
388 
389 	/*
390 	 * Set divisors to 1 (normal case) and let the machine-specific
391 	 * code do its bit.
392 	 */
393 	mtx_init(&time_lock, "time lock", NULL, MTX_DEF);
394 	cpu_initclocks();
395 
396 	/*
397 	 * Compute profhz/stathz, and fix profhz if needed.
398 	 */
399 	i = stathz ? stathz : hz;
400 	if (profhz == 0)
401 		profhz = i;
402 	psratio = profhz / i;
403 #ifdef SW_WATCHDOG
404 	EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
405 #endif
406 }
407 
408 /*
409  * Each time the real-time timer fires, this function is called on all CPUs.
410  * Note that hardclock() calls hardclock_cpu() for the boot CPU, so only
411  * the other CPUs in the system need to call this function.
412  */
413 void
414 hardclock_cpu(int usermode)
415 {
416 	struct pstats *pstats;
417 	struct thread *td = curthread;
418 	struct proc *p = td->td_proc;
419 	int flags;
420 
421 	/*
422 	 * Run current process's virtual and profile time, as needed.
423 	 */
424 	pstats = p->p_stats;
425 	flags = 0;
426 	if (usermode &&
427 	    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) {
428 		PROC_SLOCK(p);
429 		if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
430 			flags |= TDF_ALRMPEND | TDF_ASTPENDING;
431 		PROC_SUNLOCK(p);
432 	}
433 	if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) {
434 		PROC_SLOCK(p);
435 		if (itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
436 			flags |= TDF_PROFPEND | TDF_ASTPENDING;
437 		PROC_SUNLOCK(p);
438 	}
439 	thread_lock(td);
440 	sched_tick(1);
441 	td->td_flags |= flags;
442 	thread_unlock(td);
443 
444 #ifdef	HWPMC_HOOKS
445 	if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
446 		PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
447 #endif
448 	callout_tick();
449 }
450 
451 /*
452  * The real-time timer, interrupting hz times per second.
453  */
454 void
455 hardclock(int usermode, uintfptr_t pc)
456 {
457 
458 	atomic_add_int((volatile int *)&ticks, 1);
459 	hardclock_cpu(usermode);
460 	tc_ticktock(1);
461 	cpu_tick_calibration();
462 	/*
463 	 * If no separate statistics clock is available, run it from here.
464 	 *
465 	 * XXX: this only works for UP
466 	 */
467 	if (stathz == 0) {
468 		profclock(usermode, pc);
469 		statclock(usermode);
470 	}
471 #ifdef DEVICE_POLLING
472 	hardclock_device_poll();	/* this is very short and quick */
473 #endif /* DEVICE_POLLING */
474 #ifdef SW_WATCHDOG
475 	if (watchdog_enabled > 0 && --watchdog_ticks <= 0)
476 		watchdog_fire();
477 #endif /* SW_WATCHDOG */
478 }
479 
480 void
481 hardclock_anycpu(int cnt, int usermode)
482 {
483 	struct pstats *pstats;
484 	struct thread *td = curthread;
485 	struct proc *p = td->td_proc;
486 	int *t = DPCPU_PTR(pcputicks);
487 	int flags, global, newticks;
488 #ifdef SW_WATCHDOG
489 	int i;
490 #endif /* SW_WATCHDOG */
491 
492 	/*
493 	 * Update per-CPU and possibly global ticks values.
494 	 */
495 	*t += cnt;
496 	do {
497 		global = ticks;
498 		newticks = *t - global;
499 		if (newticks <= 0) {
500 			if (newticks < -1)
501 				*t = global - 1;
502 			newticks = 0;
503 			break;
504 		}
505 	} while (!atomic_cmpset_int(&ticks, global, *t));
506 
507 	/*
508 	 * Run current process's virtual and profile time, as needed.
509 	 */
510 	pstats = p->p_stats;
511 	flags = 0;
512 	if (usermode &&
513 	    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value)) {
514 		PROC_SLOCK(p);
515 		if (itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL],
516 		    tick * cnt) == 0)
517 			flags |= TDF_ALRMPEND | TDF_ASTPENDING;
518 		PROC_SUNLOCK(p);
519 	}
520 	if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value)) {
521 		PROC_SLOCK(p);
522 		if (itimerdecr(&pstats->p_timer[ITIMER_PROF],
523 		    tick * cnt) == 0)
524 			flags |= TDF_PROFPEND | TDF_ASTPENDING;
525 		PROC_SUNLOCK(p);
526 	}
527 	thread_lock(td);
528 	sched_tick(cnt);
529 	td->td_flags |= flags;
530 	thread_unlock(td);
531 
532 #ifdef	HWPMC_HOOKS
533 	if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
534 		PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
535 #endif
536 	callout_tick();
537 	/* We are in charge to handle this tick duty. */
538 	if (newticks > 0) {
539 		/* Dangerous and no need to call these things concurrently. */
540 		if (atomic_cmpset_acq_int(&global_hardclock_run, 0, 1)) {
541 			tc_ticktock(newticks);
542 #ifdef DEVICE_POLLING
543 			/* This is very short and quick. */
544 			hardclock_device_poll();
545 #endif /* DEVICE_POLLING */
546 			atomic_store_rel_int(&global_hardclock_run, 0);
547 		}
548 #ifdef SW_WATCHDOG
549 		if (watchdog_enabled > 0) {
550 			i = atomic_fetchadd_int(&watchdog_ticks, -newticks);
551 			if (i > 0 && i <= newticks)
552 				watchdog_fire();
553 		}
554 #endif /* SW_WATCHDOG */
555 	}
556 	if (curcpu == CPU_FIRST())
557 		cpu_tick_calibration();
558 }
559 
560 void
561 hardclock_sync(int cpu)
562 {
563 	int	*t = DPCPU_ID_PTR(cpu, pcputicks);
564 
565 	*t = ticks;
566 }
567 
568 /*
569  * Compute number of ticks in the specified amount of time.
570  */
571 int
572 tvtohz(tv)
573 	struct timeval *tv;
574 {
575 	register unsigned long ticks;
576 	register long sec, usec;
577 
578 	/*
579 	 * If the number of usecs in the whole seconds part of the time
580 	 * difference fits in a long, then the total number of usecs will
581 	 * fit in an unsigned long.  Compute the total and convert it to
582 	 * ticks, rounding up and adding 1 to allow for the current tick
583 	 * to expire.  Rounding also depends on unsigned long arithmetic
584 	 * to avoid overflow.
585 	 *
586 	 * Otherwise, if the number of ticks in the whole seconds part of
587 	 * the time difference fits in a long, then convert the parts to
588 	 * ticks separately and add, using similar rounding methods and
589 	 * overflow avoidance.  This method would work in the previous
590 	 * case but it is slightly slower and assumes that hz is integral.
591 	 *
592 	 * Otherwise, round the time difference down to the maximum
593 	 * representable value.
594 	 *
595 	 * If ints have 32 bits, then the maximum value for any timeout in
596 	 * 10ms ticks is 248 days.
597 	 */
598 	sec = tv->tv_sec;
599 	usec = tv->tv_usec;
600 	if (usec < 0) {
601 		sec--;
602 		usec += 1000000;
603 	}
604 	if (sec < 0) {
605 #ifdef DIAGNOSTIC
606 		if (usec > 0) {
607 			sec++;
608 			usec -= 1000000;
609 		}
610 		printf("tvotohz: negative time difference %ld sec %ld usec\n",
611 		       sec, usec);
612 #endif
613 		ticks = 1;
614 	} else if (sec <= LONG_MAX / 1000000)
615 		ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
616 			/ tick + 1;
617 	else if (sec <= LONG_MAX / hz)
618 		ticks = sec * hz
619 			+ ((unsigned long)usec + (tick - 1)) / tick + 1;
620 	else
621 		ticks = LONG_MAX;
622 	if (ticks > INT_MAX)
623 		ticks = INT_MAX;
624 	return ((int)ticks);
625 }
626 
627 /*
628  * Start profiling on a process.
629  *
630  * Kernel profiling passes proc0 which never exits and hence
631  * keeps the profile clock running constantly.
632  */
633 void
634 startprofclock(p)
635 	register struct proc *p;
636 {
637 
638 	PROC_LOCK_ASSERT(p, MA_OWNED);
639 	if (p->p_flag & P_STOPPROF)
640 		return;
641 	if ((p->p_flag & P_PROFIL) == 0) {
642 		p->p_flag |= P_PROFIL;
643 		mtx_lock(&time_lock);
644 		if (++profprocs == 1)
645 			cpu_startprofclock();
646 		mtx_unlock(&time_lock);
647 	}
648 }
649 
650 /*
651  * Stop profiling on a process.
652  */
653 void
654 stopprofclock(p)
655 	register struct proc *p;
656 {
657 
658 	PROC_LOCK_ASSERT(p, MA_OWNED);
659 	if (p->p_flag & P_PROFIL) {
660 		if (p->p_profthreads != 0) {
661 			p->p_flag |= P_STOPPROF;
662 			while (p->p_profthreads != 0)
663 				msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
664 				    "stopprof", 0);
665 			p->p_flag &= ~P_STOPPROF;
666 		}
667 		if ((p->p_flag & P_PROFIL) == 0)
668 			return;
669 		p->p_flag &= ~P_PROFIL;
670 		mtx_lock(&time_lock);
671 		if (--profprocs == 0)
672 			cpu_stopprofclock();
673 		mtx_unlock(&time_lock);
674 	}
675 }
676 
677 /*
678  * Statistics clock.  Updates rusage information and calls the scheduler
679  * to adjust priorities of the active thread.
680  *
681  * This should be called by all active processors.
682  */
683 void
684 statclock(int usermode)
685 {
686 	struct rusage *ru;
687 	struct vmspace *vm;
688 	struct thread *td;
689 	struct proc *p;
690 	long rss;
691 	long *cp_time;
692 
693 	td = curthread;
694 	p = td->td_proc;
695 
696 	cp_time = (long *)PCPU_PTR(cp_time);
697 	if (usermode) {
698 		/*
699 		 * Charge the time as appropriate.
700 		 */
701 		td->td_uticks++;
702 		if (p->p_nice > NZERO)
703 			cp_time[CP_NICE]++;
704 		else
705 			cp_time[CP_USER]++;
706 	} else {
707 		/*
708 		 * Came from kernel mode, so we were:
709 		 * - handling an interrupt,
710 		 * - doing syscall or trap work on behalf of the current
711 		 *   user process, or
712 		 * - spinning in the idle loop.
713 		 * Whichever it is, charge the time as appropriate.
714 		 * Note that we charge interrupts to the current process,
715 		 * regardless of whether they are ``for'' that process,
716 		 * so that we know how much of its real time was spent
717 		 * in ``non-process'' (i.e., interrupt) work.
718 		 */
719 		if ((td->td_pflags & TDP_ITHREAD) ||
720 		    td->td_intr_nesting_level >= 2) {
721 			td->td_iticks++;
722 			cp_time[CP_INTR]++;
723 		} else {
724 			td->td_pticks++;
725 			td->td_sticks++;
726 			if (!TD_IS_IDLETHREAD(td))
727 				cp_time[CP_SYS]++;
728 			else
729 				cp_time[CP_IDLE]++;
730 		}
731 	}
732 
733 	/* Update resource usage integrals and maximums. */
734 	MPASS(p->p_vmspace != NULL);
735 	vm = p->p_vmspace;
736 	ru = &td->td_ru;
737 	ru->ru_ixrss += pgtok(vm->vm_tsize);
738 	ru->ru_idrss += pgtok(vm->vm_dsize);
739 	ru->ru_isrss += pgtok(vm->vm_ssize);
740 	rss = pgtok(vmspace_resident_count(vm));
741 	if (ru->ru_maxrss < rss)
742 		ru->ru_maxrss = rss;
743 	KTR_POINT2(KTR_SCHED, "thread", sched_tdname(td), "statclock",
744 	    "prio:%d", td->td_priority, "stathz:%d", (stathz)?stathz:hz);
745 	thread_lock_flags(td, MTX_QUIET);
746 	sched_clock(td);
747 	thread_unlock(td);
748 }
749 
750 void
751 profclock(int usermode, uintfptr_t pc)
752 {
753 	struct thread *td;
754 #ifdef GPROF
755 	struct gmonparam *g;
756 	uintfptr_t i;
757 #endif
758 
759 	td = curthread;
760 	if (usermode) {
761 		/*
762 		 * Came from user mode; CPU was in user state.
763 		 * If this process is being profiled, record the tick.
764 		 * if there is no related user location yet, don't
765 		 * bother trying to count it.
766 		 */
767 		if (td->td_proc->p_flag & P_PROFIL)
768 			addupc_intr(td, pc, 1);
769 	}
770 #ifdef GPROF
771 	else {
772 		/*
773 		 * Kernel statistics are just like addupc_intr, only easier.
774 		 */
775 		g = &_gmonparam;
776 		if (g->state == GMON_PROF_ON && pc >= g->lowpc) {
777 			i = PC_TO_I(g, pc);
778 			if (i < g->textsize) {
779 				KCOUNT(g, i)++;
780 			}
781 		}
782 	}
783 #endif
784 }
785 
786 /*
787  * Return information about system clocks.
788  */
789 static int
790 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
791 {
792 	struct clockinfo clkinfo;
793 	/*
794 	 * Construct clockinfo structure.
795 	 */
796 	bzero(&clkinfo, sizeof(clkinfo));
797 	clkinfo.hz = hz;
798 	clkinfo.tick = tick;
799 	clkinfo.profhz = profhz;
800 	clkinfo.stathz = stathz ? stathz : hz;
801 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
802 }
803 
804 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate,
805 	CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_MPSAFE,
806 	0, 0, sysctl_kern_clockrate, "S,clockinfo",
807 	"Rate and period of various kernel clocks");
808 
809 #ifdef SW_WATCHDOG
810 
811 static void
812 watchdog_config(void *unused __unused, u_int cmd, int *error)
813 {
814 	u_int u;
815 
816 	u = cmd & WD_INTERVAL;
817 	if (u >= WD_TO_1SEC) {
818 		watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
819 		watchdog_enabled = 1;
820 		*error = 0;
821 	} else {
822 		watchdog_enabled = 0;
823 	}
824 }
825 
826 /*
827  * Handle a watchdog timeout by dumping interrupt information and
828  * then either dropping to DDB or panicking.
829  */
830 static void
831 watchdog_fire(void)
832 {
833 	int nintr;
834 	uint64_t inttotal;
835 	u_long *curintr;
836 	char *curname;
837 
838 	curintr = intrcnt;
839 	curname = intrnames;
840 	inttotal = 0;
841 	nintr = eintrcnt - intrcnt;
842 
843 	printf("interrupt                   total\n");
844 	while (--nintr >= 0) {
845 		if (*curintr)
846 			printf("%-12s %20lu\n", curname, *curintr);
847 		curname += strlen(curname) + 1;
848 		inttotal += *curintr++;
849 	}
850 	printf("Total        %20ju\n", (uintmax_t)inttotal);
851 
852 #if defined(KDB) && !defined(KDB_UNATTENDED)
853 	kdb_backtrace();
854 	kdb_enter(KDB_WHY_WATCHDOG, "watchdog timeout");
855 #else
856 	panic("watchdog timeout");
857 #endif
858 }
859 
860 #endif /* SW_WATCHDOG */
861