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.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
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.
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
34 * @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
41 #include "opt_watchdog.h"
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/callout.h>
47 #include <sys/kernel.h>
50 #include <sys/mutex.h>
52 #include <sys/resource.h>
53 #include <sys/resourcevar.h>
54 #include <sys/sched.h>
55 #include <sys/signalvar.h>
59 #include <vm/vm_map.h>
60 #include <sys/sysctl.h>
62 #include <sys/interrupt.h>
63 #include <sys/limits.h>
64 #include <sys/timetc.h>
66 #include <machine/cpu.h>
73 #include <sys/pmckern.h>
77 extern void hardclock_device_poll(void);
78 #endif /* DEVICE_POLLING */
80 static void initclocks(void *dummy);
81 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
83 /* Some of these don't belong here, but it's easiest to concentrate them. */
84 long cp_time[CPUSTATES];
86 SYSCTL_OPAQUE(_kern, OID_AUTO, cp_time, CTLFLAG_RD, &cp_time, sizeof(cp_time),
87 "LU", "CPU time statistics");
90 #include <sys/watchdog.h>
92 static int watchdog_ticks;
93 static int watchdog_enabled;
94 static void watchdog_fire(void);
95 static void watchdog_config(void *, u_int, int *);
96 #endif /* SW_WATCHDOG */
99 * Clock handling routines.
101 * This code is written to operate with two timers that run independently of
104 * The main timer, running hz times per second, is used to trigger interval
105 * timers, timeouts and rescheduling as needed.
107 * The second timer handles kernel and user profiling,
108 * and does resource use estimation. If the second timer is programmable,
109 * it is randomized to avoid aliasing between the two clocks. For example,
110 * the randomization prevents an adversary from always giving up the cpu
111 * just before its quantum expires. Otherwise, it would never accumulate
112 * cpu ticks. The mean frequency of the second timer is stathz.
114 * If no second timer exists, stathz will be zero; in this case we drive
115 * profiling and statistics off the main clock. This WILL NOT be accurate;
116 * do not do it unless absolutely necessary.
118 * The statistics clock may (or may not) be run at a higher rate while
119 * profiling. This profile clock runs at profhz. We require that profhz
120 * be an integral multiple of stathz.
122 * If the statistics clock is running fast, it must be divided by the ratio
123 * profhz/stathz for statistics. (For profiling, every tick counts.)
125 * Time-of-day is maintained using a "timecounter", which may or may
126 * not be related to the hardware generating the above mentioned
137 * Initialize clock frequencies and start both clocks running.
147 * Set divisors to 1 (normal case) and let the machine-specific
153 * Compute profhz/stathz, and fix profhz if needed.
155 i = stathz ? stathz : hz;
158 psratio = profhz / i;
160 EVENTHANDLER_REGISTER(watchdog_list, watchdog_config, NULL, 0);
165 * Each time the real-time timer fires, this function is called on all CPUs.
166 * Note that hardclock() calls hardclock_process() for the boot CPU, so only
167 * the other CPUs in the system need to call this function.
170 hardclock_process(frame)
171 register struct clockframe *frame;
173 struct pstats *pstats;
174 struct thread *td = curthread;
175 struct proc *p = td->td_proc;
178 * Run current process's virtual and profile time, as needed.
180 mtx_lock_spin_flags(&sched_lock, MTX_QUIET);
181 if (p->p_flag & P_SA) {
182 /* XXXKSE What to do? */
185 if (CLKF_USERMODE(frame) &&
186 timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
187 itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0) {
188 p->p_sflag |= PS_ALRMPEND;
189 td->td_flags |= TDF_ASTPENDING;
191 if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
192 itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0) {
193 p->p_sflag |= PS_PROFPEND;
194 td->td_flags |= TDF_ASTPENDING;
197 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET);
200 if (PMC_CPU_HAS_SAMPLES(PCPU_GET(cpuid)))
201 PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
206 * The real-time timer, interrupting hz times per second.
210 register struct clockframe *frame;
212 int need_softclock = 0;
214 CTR0(KTR_CLK, "hardclock fired");
215 hardclock_process(frame);
219 * If no separate statistics clock is available, run it from here.
221 * XXX: this only works for UP
228 #ifdef DEVICE_POLLING
229 hardclock_device_poll(); /* this is very short and quick */
230 #endif /* DEVICE_POLLING */
233 * Process callouts at a very low cpu priority, so we don't keep the
234 * relatively high clock interrupt priority any longer than necessary.
236 mtx_lock_spin_flags(&callout_lock, MTX_QUIET);
238 if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) {
240 } else if (softticks + 1 == ticks)
242 mtx_unlock_spin_flags(&callout_lock, MTX_QUIET);
245 * swi_sched acquires sched_lock, so we don't want to call it with
246 * callout_lock held; incorrect locking order.
249 swi_sched(softclock_ih, 0);
252 if (watchdog_enabled > 0 && --watchdog_ticks <= 0)
254 #endif /* SW_WATCHDOG */
258 * Compute number of ticks in the specified amount of time.
264 register unsigned long ticks;
265 register long sec, usec;
268 * If the number of usecs in the whole seconds part of the time
269 * difference fits in a long, then the total number of usecs will
270 * fit in an unsigned long. Compute the total and convert it to
271 * ticks, rounding up and adding 1 to allow for the current tick
272 * to expire. Rounding also depends on unsigned long arithmetic
275 * Otherwise, if the number of ticks in the whole seconds part of
276 * the time difference fits in a long, then convert the parts to
277 * ticks separately and add, using similar rounding methods and
278 * overflow avoidance. This method would work in the previous
279 * case but it is slightly slower and assumes that hz is integral.
281 * Otherwise, round the time difference down to the maximum
282 * representable value.
284 * If ints have 32 bits, then the maximum value for any timeout in
285 * 10ms ticks is 248 days.
299 printf("tvotohz: negative time difference %ld sec %ld usec\n",
303 } else if (sec <= LONG_MAX / 1000000)
304 ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
306 else if (sec <= LONG_MAX / hz)
308 + ((unsigned long)usec + (tick - 1)) / tick + 1;
317 * Start profiling on a process.
319 * Kernel profiling passes proc0 which never exits and hence
320 * keeps the profile clock running constantly.
324 register struct proc *p;
328 * XXX; Right now sched_lock protects statclock(), but perhaps
329 * it should be protected later on by a time_lock, which would
330 * cover psdiv, etc. as well.
332 PROC_LOCK_ASSERT(p, MA_OWNED);
333 if (p->p_flag & P_STOPPROF)
335 if ((p->p_flag & P_PROFIL) == 0) {
336 mtx_lock_spin(&sched_lock);
337 p->p_flag |= P_PROFIL;
338 if (++profprocs == 1)
339 cpu_startprofclock();
340 mtx_unlock_spin(&sched_lock);
345 * Stop profiling on a process.
349 register struct proc *p;
352 PROC_LOCK_ASSERT(p, MA_OWNED);
353 if (p->p_flag & P_PROFIL) {
354 if (p->p_profthreads != 0) {
355 p->p_flag |= P_STOPPROF;
356 while (p->p_profthreads != 0)
357 msleep(&p->p_profthreads, &p->p_mtx, PPAUSE,
359 p->p_flag &= ~P_STOPPROF;
361 if ((p->p_flag & P_PROFIL) == 0)
363 mtx_lock_spin(&sched_lock);
364 p->p_flag &= ~P_PROFIL;
365 if (--profprocs == 0)
367 mtx_unlock_spin(&sched_lock);
372 * Statistics clock. Grab profile sample, and if divider reaches 0,
373 * do process and kernel statistics. Most of the statistics are only
374 * used by user-level statistics programs. The main exceptions are
375 * ke->ke_uticks, p->p_rux.rux_sticks, p->p_rux.rux_iticks, and p->p_estcpu.
376 * This should be called by all active processors.
380 register struct clockframe *frame;
391 mtx_lock_spin_flags(&sched_lock, MTX_QUIET);
392 if (CLKF_USERMODE(frame)) {
394 * Charge the time as appropriate.
396 if (p->p_flag & P_SA)
398 p->p_rux.rux_uticks++;
399 if (p->p_nice > NZERO)
405 * Came from kernel mode, so we were:
406 * - handling an interrupt,
407 * - doing syscall or trap work on behalf of the current
409 * - spinning in the idle loop.
410 * Whichever it is, charge the time as appropriate.
411 * Note that we charge interrupts to the current process,
412 * regardless of whether they are ``for'' that process,
413 * so that we know how much of its real time was spent
414 * in ``non-process'' (i.e., interrupt) work.
416 if ((td->td_ithd != NULL) || td->td_intr_nesting_level >= 2) {
417 p->p_rux.rux_iticks++;
420 if (p->p_flag & P_SA)
423 p->p_rux.rux_sticks++;
424 if (p != PCPU_GET(idlethread)->td_proc)
430 CTR4(KTR_SCHED, "statclock: %p(%s) prio %d stathz %d",
431 td, td->td_proc->p_comm, td->td_priority, (stathz)?stathz:hz);
435 /* Update resource usage integrals and maximums. */
436 MPASS(p->p_stats != NULL);
437 MPASS(p->p_vmspace != NULL);
439 ru = &p->p_stats->p_ru;
440 ru->ru_ixrss += pgtok(vm->vm_tsize);
441 ru->ru_idrss += pgtok(vm->vm_dsize);
442 ru->ru_isrss += pgtok(vm->vm_ssize);
443 rss = pgtok(vmspace_resident_count(vm));
444 if (ru->ru_maxrss < rss)
446 mtx_unlock_spin_flags(&sched_lock, MTX_QUIET);
451 register struct clockframe *frame;
460 if (CLKF_USERMODE(frame)) {
462 * Came from user mode; CPU was in user state.
463 * If this process is being profiled, record the tick.
464 * if there is no related user location yet, don't
465 * bother trying to count it.
467 if (td->td_proc->p_flag & P_PROFIL)
468 addupc_intr(td, CLKF_PC(frame), 1);
473 * Kernel statistics are just like addupc_intr, only easier.
476 if (g->state == GMON_PROF_ON) {
477 i = CLKF_PC(frame) - g->lowpc;
478 if (i < g->textsize) {
479 i /= HISTFRACTION * sizeof(*g->kcount);
488 * Return information about system clocks.
491 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
493 struct clockinfo clkinfo;
495 * Construct clockinfo structure.
497 bzero(&clkinfo, sizeof(clkinfo));
500 clkinfo.profhz = profhz;
501 clkinfo.stathz = stathz ? stathz : hz;
502 return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
505 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
506 0, 0, sysctl_kern_clockrate, "S,clockinfo",
507 "Rate and period of various kernel clocks");
512 watchdog_config(void *unused __unused, u_int cmd, int *err)
516 u = cmd & WD_INTERVAL;
517 if (cmd && u >= WD_TO_1SEC) {
518 u = cmd & WD_INTERVAL;
519 watchdog_ticks = (1 << (u - WD_TO_1SEC)) * hz;
520 watchdog_enabled = 1;
523 watchdog_enabled = 0;
528 * Handle a watchdog timeout by dumping interrupt information and
529 * then either dropping to DDB or panicing.
542 nintr = eintrcnt - intrcnt;
544 printf("interrupt total\n");
545 while (--nintr >= 0) {
547 printf("%-12s %20lu\n", curname, *curintr);
548 curname += strlen(curname) + 1;
549 inttotal += *curintr++;
551 printf("Total %20ju\n", (uintmax_t)inttotal);
555 kdb_enter("watchdog timeout");
557 panic("watchdog timeout");
561 #endif /* SW_WATCHDOG */