xref: /dflybsd-src/sys/kern/kern_clock.c (revision 871020e7804af32d9a544b48cd250fa49fcbb269)
1 /*
2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * Copyright (c) 1997, 1998 Poul-Henning Kamp <phk@FreeBSD.org>
35  * Copyright (c) 1982, 1986, 1991, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  * (c) UNIX System Laboratories, Inc.
38  * All or some portions of this file are derived from material licensed
39  * to the University of California by American Telephone and Telegraph
40  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
41  * the permission of UNIX System Laboratories, Inc.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  *
71  *	@(#)kern_clock.c	8.5 (Berkeley) 1/21/94
72  * $FreeBSD: src/sys/kern/kern_clock.c,v 1.105.2.10 2002/10/17 13:19:40 maxim Exp $
73  * $DragonFly: src/sys/kern/kern_clock.c,v 1.38 2005/04/24 02:01:08 dillon Exp $
74  */
75 
76 #include "opt_ntp.h"
77 
78 #include <sys/param.h>
79 #include <sys/systm.h>
80 #include <sys/dkstat.h>
81 #include <sys/callout.h>
82 #include <sys/kernel.h>
83 #include <sys/kinfo.h>
84 #include <sys/proc.h>
85 #include <sys/malloc.h>
86 #include <sys/resourcevar.h>
87 #include <sys/signalvar.h>
88 #include <sys/timex.h>
89 #include <sys/timepps.h>
90 #include <vm/vm.h>
91 #include <sys/lock.h>
92 #include <vm/pmap.h>
93 #include <vm/vm_map.h>
94 #include <sys/sysctl.h>
95 #include <sys/thread2.h>
96 
97 #include <machine/cpu.h>
98 #include <machine/limits.h>
99 #include <machine/smp.h>
100 
101 #ifdef GPROF
102 #include <sys/gmon.h>
103 #endif
104 
105 #ifdef DEVICE_POLLING
106 extern void init_device_poll(void);
107 extern void hardclock_device_poll(void);
108 #endif /* DEVICE_POLLING */
109 
110 static void initclocks (void *dummy);
111 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
112 
113 /*
114  * Some of these don't belong here, but it's easiest to concentrate them.
115  * Note that cp_time counts in microseconds, but most userland programs
116  * just compare relative times against the total by delta.
117  */
118 struct cp_time cp_time;
119 
120 SYSCTL_OPAQUE(_kern, OID_AUTO, cp_time, CTLFLAG_RD, &cp_time, sizeof(cp_time),
121     "LU", "CPU time statistics");
122 
123 /*
124  * boottime is used to calculate the 'real' uptime.  Do not confuse this with
125  * microuptime().  microtime() is not drift compensated.  The real uptime
126  * with compensation is nanotime() - bootime.  boottime is recalculated
127  * whenever the real time is set based on the compensated elapsed time
128  * in seconds (gd->gd_time_seconds).
129  *
130  * The gd_time_seconds and gd_cpuclock_base fields remain fairly monotonic.
131  * Slight adjustments to gd_cpuclock_base are made to phase-lock it to
132  * the real time.
133  */
134 struct timespec boottime;	/* boot time (realtime) for reference only */
135 time_t time_second;		/* read-only 'passive' uptime in seconds */
136 
137 /*
138  * basetime is used to calculate the compensated real time of day.  The
139  * basetime can be modified on a per-tick basis by the adjtime(),
140  * ntp_adjtime(), and sysctl-based time correction APIs.
141  *
142  * Note that frequency corrections can also be made by adjusting
143  * gd_cpuclock_base.
144  *
145  * basetime is a tail-chasing FIFO, updated only by cpu #0.  The FIFO is
146  * used on both SMP and UP systems to avoid MP races between cpu's and
147  * interrupt races on UP systems.
148  */
149 #define BASETIME_ARYSIZE	16
150 #define BASETIME_ARYMASK	(BASETIME_ARYSIZE - 1)
151 static struct timespec basetime[BASETIME_ARYSIZE];
152 static volatile int basetime_index;
153 
154 static int
155 sysctl_get_basetime(SYSCTL_HANDLER_ARGS)
156 {
157 	struct timespec *bt;
158 	int error;
159 
160 	bt = &basetime[basetime_index];
161 	error = SYSCTL_OUT(req, bt, sizeof(*bt));
162 	return (error);
163 }
164 
165 SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime, CTLFLAG_RD,
166     &boottime, timespec, "System boottime");
167 SYSCTL_PROC(_kern, OID_AUTO, basetime, CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0,
168     sysctl_get_basetime, "S,timespec", "System basetime");
169 
170 static void hardclock(systimer_t info, struct intrframe *frame);
171 static void statclock(systimer_t info, struct intrframe *frame);
172 static void schedclock(systimer_t info, struct intrframe *frame);
173 static void getnanotime_nbt(struct timespec *nbt, struct timespec *tsp);
174 
175 int	ticks;			/* system master ticks at hz */
176 int	clocks_running;		/* tsleep/timeout clocks operational */
177 int64_t	nsec_adj;		/* ntpd per-tick adjustment in nsec << 32 */
178 int64_t	nsec_acc;		/* accumulator */
179 
180 /* NTPD time correction fields */
181 int64_t	ntp_tick_permanent;	/* per-tick adjustment in nsec << 32 */
182 int64_t	ntp_tick_acc;		/* accumulator for per-tick adjustment */
183 int64_t	ntp_delta;		/* one-time correction in nsec */
184 int64_t ntp_big_delta = 1000000000;
185 int32_t	ntp_tick_delta;		/* current adjustment rate */
186 int32_t	ntp_default_tick_delta;	/* adjustment rate for ntp_delta */
187 time_t	ntp_leap_second;	/* time of next leap second */
188 int	ntp_leap_insert;	/* whether to insert or remove a second */
189 
190 /*
191  * Finish initializing clock frequencies and start all clocks running.
192  */
193 /* ARGSUSED*/
194 static void
195 initclocks(void *dummy)
196 {
197 	cpu_initclocks();
198 #ifdef DEVICE_POLLING
199 	init_device_poll();
200 #endif
201 	/*psratio = profhz / stathz;*/
202 	initclocks_pcpu();
203 	clocks_running = 1;
204 }
205 
206 /*
207  * Called on a per-cpu basis
208  */
209 void
210 initclocks_pcpu(void)
211 {
212 	struct globaldata *gd = mycpu;
213 
214 	crit_enter();
215 	if (gd->gd_cpuid == 0) {
216 	    gd->gd_time_seconds = 1;
217 	    gd->gd_cpuclock_base = cputimer_count();
218 	} else {
219 	    /* XXX */
220 	    gd->gd_time_seconds = globaldata_find(0)->gd_time_seconds;
221 	    gd->gd_cpuclock_base = globaldata_find(0)->gd_cpuclock_base;
222 	}
223 
224 	/*
225 	 * Use a non-queued periodic systimer to prevent multiple ticks from
226 	 * building up if the sysclock jumps forward (8254 gets reset).  The
227 	 * sysclock will never jump backwards.  Our time sync is based on
228 	 * the actual sysclock, not the ticks count.
229 	 */
230 	systimer_init_periodic_nq(&gd->gd_hardclock, hardclock, NULL, hz);
231 	systimer_init_periodic_nq(&gd->gd_statclock, statclock, NULL, stathz);
232 	/* XXX correct the frequency for scheduler / estcpu tests */
233 	systimer_init_periodic_nq(&gd->gd_schedclock, schedclock,
234 				NULL, ESTCPUFREQ);
235 	crit_exit();
236 }
237 
238 /*
239  * This sets the current real time of day.  Timespecs are in seconds and
240  * nanoseconds.  We do not mess with gd_time_seconds and gd_cpuclock_base,
241  * instead we adjust basetime so basetime + gd_* results in the current
242  * time of day.  This way the gd_* fields are guarenteed to represent
243  * a monotonically increasing 'uptime' value.
244  *
245  * When set_timeofday() is called from userland, the system call forces it
246  * onto cpu #0 since only cpu #0 can update basetime_index.
247  */
248 void
249 set_timeofday(struct timespec *ts)
250 {
251 	struct timespec *nbt;
252 	int ni;
253 
254 	/*
255 	 * XXX SMP / non-atomic basetime updates
256 	 */
257 	crit_enter();
258 	ni = (basetime_index + 1) & BASETIME_ARYMASK;
259 	nbt = &basetime[ni];
260 	nanouptime(nbt);
261 	nbt->tv_sec = ts->tv_sec - nbt->tv_sec;
262 	nbt->tv_nsec = ts->tv_nsec - nbt->tv_nsec;
263 	if (nbt->tv_nsec < 0) {
264 	    nbt->tv_nsec += 1000000000;
265 	    --nbt->tv_sec;
266 	}
267 
268 	/*
269 	 * Note that basetime diverges from boottime as the clock drift is
270 	 * compensated for, so we cannot do away with boottime.  When setting
271 	 * the absolute time of day the drift is 0 (for an instant) and we
272 	 * can simply assign boottime to basetime.
273 	 *
274 	 * Note that nanouptime() is based on gd_time_seconds which is drift
275 	 * compensated up to a point (it is guarenteed to remain monotonically
276 	 * increasing).  gd_time_seconds is thus our best uptime guess and
277 	 * suitable for use in the boottime calculation.  It is already taken
278 	 * into account in the basetime calculation above.
279 	 */
280 	boottime.tv_sec = nbt->tv_sec;
281 	ntp_delta = 0;
282 
283 	/*
284 	 * We now have a new basetime, update the index.
285 	 */
286 	cpu_mb1();
287 	basetime_index = ni;
288 
289 	crit_exit();
290 }
291 
292 /*
293  * Each cpu has its own hardclock, but we only increments ticks and softticks
294  * on cpu #0.
295  *
296  * NOTE! systimer! the MP lock might not be held here.  We can only safely
297  * manipulate objects owned by the current cpu.
298  */
299 static void
300 hardclock(systimer_t info, struct intrframe *frame)
301 {
302 	sysclock_t cputicks;
303 	struct proc *p;
304 	struct pstats *pstats;
305 	struct globaldata *gd = mycpu;
306 
307 	/*
308 	 * Realtime updates are per-cpu.  Note that timer corrections as
309 	 * returned by microtime() and friends make an additional adjustment
310 	 * using a system-wise 'basetime', but the running time is always
311 	 * taken from the per-cpu globaldata area.  Since the same clock
312 	 * is distributing (XXX SMP) to all cpus, the per-cpu timebases
313 	 * stay in synch.
314 	 *
315 	 * Note that we never allow info->time (aka gd->gd_hardclock.time)
316 	 * to reverse index gd_cpuclock_base, but that it is possible for
317 	 * it to temporarily get behind in the seconds if something in the
318 	 * system locks interrupts for a long period of time.  Since periodic
319 	 * timers count events, though everything should resynch again
320 	 * immediately.
321 	 */
322 	cputicks = info->time - gd->gd_cpuclock_base;
323 	if (cputicks >= cputimer_freq) {
324 		++gd->gd_time_seconds;
325 		gd->gd_cpuclock_base += cputimer_freq;
326 	}
327 
328 	/*
329 	 * The system-wide ticks counter and NTP related timedelta/tickdelta
330 	 * adjustments only occur on cpu #0.  NTP adjustments are accomplished
331 	 * by updating basetime.
332 	 */
333 	if (gd->gd_cpuid == 0) {
334 	    struct timespec *nbt;
335 	    struct timespec nts;
336 	    int leap;
337 	    int ni;
338 
339 	    ++ticks;
340 
341 #ifdef DEVICE_POLLING
342 	    hardclock_device_poll();	/* mpsafe, short and quick */
343 #endif /* DEVICE_POLLING */
344 
345 #if 0
346 	    if (tco->tc_poll_pps)
347 		tco->tc_poll_pps(tco);
348 #endif
349 
350 	    /*
351 	     * Calculate the new basetime index.  We are in a critical section
352 	     * on cpu #0 and can safely play with basetime_index.  Start
353 	     * with the current basetime and then make adjustments.
354 	     */
355 	    ni = (basetime_index + 1) & BASETIME_ARYMASK;
356 	    nbt = &basetime[ni];
357 	    *nbt = basetime[basetime_index];
358 
359 	    /*
360 	     * Apply adjtime corrections.  (adjtime() API)
361 	     *
362 	     * adjtime() only runs on cpu #0 so our critical section is
363 	     * sufficient to access these variables.
364 	     */
365 	    if (ntp_delta != 0) {
366 		nbt->tv_nsec += ntp_tick_delta;
367 		ntp_delta -= ntp_tick_delta;
368 		if ((ntp_delta > 0 && ntp_delta < ntp_tick_delta) ||
369 		    (ntp_delta < 0 && ntp_delta > ntp_tick_delta)) {
370 			ntp_tick_delta = ntp_delta;
371  		}
372  	    }
373 
374 	    /*
375 	     * Apply permanent frequency corrections.  (sysctl API)
376 	     */
377 	    if (ntp_tick_permanent != 0) {
378 		ntp_tick_acc += ntp_tick_permanent;
379 		if (ntp_tick_acc >= (1LL << 32)) {
380 		    nbt->tv_nsec += ntp_tick_acc >> 32;
381 		    ntp_tick_acc -= (ntp_tick_acc >> 32) << 32;
382 		} else if (ntp_tick_acc <= -(1LL << 32)) {
383 		    /* Negate ntp_tick_acc to avoid shifting the sign bit. */
384 		    nbt->tv_nsec -= (-ntp_tick_acc) >> 32;
385 		    ntp_tick_acc += ((-ntp_tick_acc) >> 32) << 32;
386 		}
387  	    }
388 
389 	    if (nbt->tv_nsec >= 1000000000) {
390 		    nbt->tv_sec++;
391 		    nbt->tv_nsec -= 1000000000;
392 	    } else if (nbt->tv_nsec < 0) {
393 		    nbt->tv_sec--;
394 		    nbt->tv_nsec += 1000000000;
395 	    }
396 
397 	    /*
398 	     * Another per-tick compensation.  (for ntp_adjtime() API)
399 	     */
400 	    if (nsec_adj != 0) {
401 		nsec_acc += nsec_adj;
402 		if (nsec_acc >= 0x100000000LL) {
403 		    nbt->tv_nsec += nsec_acc >> 32;
404 		    nsec_acc = (nsec_acc & 0xFFFFFFFFLL);
405 		} else if (nsec_acc <= -0x100000000LL) {
406 		    nbt->tv_nsec -= -nsec_acc >> 32;
407 		    nsec_acc = -(-nsec_acc & 0xFFFFFFFFLL);
408 		}
409 		if (nbt->tv_nsec >= 1000000000) {
410 		    nbt->tv_nsec -= 1000000000;
411 		    ++nbt->tv_sec;
412 		} else if (nbt->tv_nsec < 0) {
413 		    nbt->tv_nsec += 1000000000;
414 		    --nbt->tv_sec;
415 		}
416 	    }
417 
418 	    /************************************************************
419 	     *			LEAP SECOND CORRECTION			*
420 	     ************************************************************
421 	     *
422 	     * Taking into account all the corrections made above, figure
423 	     * out the new real time.  If the seconds field has changed
424 	     * then apply any pending leap-second corrections.
425 	     */
426 	    getnanotime_nbt(nbt, &nts);
427 
428 	    /*
429 	     * Apply leap second (sysctl API)
430 	     */
431 	    if (ntp_leap_second) {
432 		if (ntp_leap_second == nts.tv_sec) {
433 			if (ntp_leap_insert)
434 				nbt->tv_sec++;
435 			else
436 				nbt->tv_sec--;
437 			ntp_leap_second--;
438 		}
439 	    }
440 
441 	    /*
442 	     * Apply leap second (ntp_adjtime() API)
443 	     */
444 	    if (time_second != nts.tv_sec) {
445 		leap = ntp_update_second(time_second, &nsec_adj);
446 		nbt->tv_sec += leap;
447 		time_second = nbt->tv_sec;
448 		nsec_adj /= hz;
449 	    }
450 
451 	    /*
452 	     * Finally, our new basetime is ready to go live!
453 	     */
454 	    cpu_mb1();
455 	    basetime_index = ni;
456 	}
457 
458 	/*
459 	 * softticks are handled for all cpus
460 	 */
461 	hardclock_softtick(gd);
462 
463 	/*
464 	 * ITimer handling is per-tick, per-cpu.  I don't think psignal()
465 	 * is mpsafe on curproc, so XXX get the mplock.
466 	 */
467 	if ((p = curproc) != NULL && try_mplock()) {
468 		pstats = p->p_stats;
469 		if (frame && CLKF_USERMODE(frame) &&
470 		    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
471 		    itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
472 			psignal(p, SIGVTALRM);
473 		if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
474 		    itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
475 			psignal(p, SIGPROF);
476 		rel_mplock();
477 	}
478 	setdelayed();
479 }
480 
481 /*
482  * The statistics clock typically runs at a 125Hz rate, and is intended
483  * to be frequency offset from the hardclock (typ 100Hz).  It is per-cpu.
484  *
485  * NOTE! systimer! the MP lock might not be held here.  We can only safely
486  * manipulate objects owned by the current cpu.
487  *
488  * The stats clock is responsible for grabbing a profiling sample.
489  * Most of the statistics are only used by user-level statistics programs.
490  * The main exceptions are p->p_uticks, p->p_sticks, p->p_iticks, and
491  * p->p_estcpu.
492  *
493  * Like the other clocks, the stat clock is called from what is effectively
494  * a fast interrupt, so the context should be the thread/process that got
495  * interrupted.
496  */
497 static void
498 statclock(systimer_t info, struct intrframe *frame)
499 {
500 #ifdef GPROF
501 	struct gmonparam *g;
502 	int i;
503 #endif
504 	thread_t td;
505 	struct proc *p;
506 	int bump;
507 	struct timeval tv;
508 	struct timeval *stv;
509 
510 	/*
511 	 * How big was our timeslice relative to the last time?
512 	 */
513 	microuptime(&tv);	/* mpsafe */
514 	stv = &mycpu->gd_stattv;
515 	if (stv->tv_sec == 0) {
516 	    bump = 1;
517 	} else {
518 	    bump = tv.tv_usec - stv->tv_usec +
519 		(tv.tv_sec - stv->tv_sec) * 1000000;
520 	    if (bump < 0)
521 		bump = 0;
522 	    if (bump > 1000000)
523 		bump = 1000000;
524 	}
525 	*stv = tv;
526 
527 	td = curthread;
528 	p = td->td_proc;
529 
530 	if (frame && CLKF_USERMODE(frame)) {
531 		/*
532 		 * Came from userland, handle user time and deal with
533 		 * possible process.
534 		 */
535 		if (p && (p->p_flag & P_PROFIL))
536 			addupc_intr(p, CLKF_PC(frame), 1);
537 		td->td_uticks += bump;
538 
539 		/*
540 		 * Charge the time as appropriate
541 		 */
542 		if (p && p->p_nice > NZERO)
543 			cp_time.cp_nice += bump;
544 		else
545 			cp_time.cp_user += bump;
546 	} else {
547 #ifdef GPROF
548 		/*
549 		 * Kernel statistics are just like addupc_intr, only easier.
550 		 */
551 		g = &_gmonparam;
552 		if (g->state == GMON_PROF_ON && frame) {
553 			i = CLKF_PC(frame) - g->lowpc;
554 			if (i < g->textsize) {
555 				i /= HISTFRACTION * sizeof(*g->kcount);
556 				g->kcount[i]++;
557 			}
558 		}
559 #endif
560 		/*
561 		 * Came from kernel mode, so we were:
562 		 * - handling an interrupt,
563 		 * - doing syscall or trap work on behalf of the current
564 		 *   user process, or
565 		 * - spinning in the idle loop.
566 		 * Whichever it is, charge the time as appropriate.
567 		 * Note that we charge interrupts to the current process,
568 		 * regardless of whether they are ``for'' that process,
569 		 * so that we know how much of its real time was spent
570 		 * in ``non-process'' (i.e., interrupt) work.
571 		 *
572 		 * XXX assume system if frame is NULL.  A NULL frame
573 		 * can occur if ipi processing is done from an splx().
574 		 */
575 		if (frame && CLKF_INTR(frame))
576 			td->td_iticks += bump;
577 		else
578 			td->td_sticks += bump;
579 
580 		if (frame && CLKF_INTR(frame)) {
581 			cp_time.cp_intr += bump;
582 		} else {
583 			if (td == &mycpu->gd_idlethread)
584 				cp_time.cp_idle += bump;
585 			else
586 				cp_time.cp_sys += bump;
587 		}
588 	}
589 }
590 
591 /*
592  * The scheduler clock typically runs at a 20Hz rate.  NOTE! systimer,
593  * the MP lock might not be held.  We can safely manipulate parts of curproc
594  * but that's about it.
595  */
596 static void
597 schedclock(systimer_t info, struct intrframe *frame)
598 {
599 	struct proc *p;
600 	struct pstats *pstats;
601 	struct rusage *ru;
602 	struct vmspace *vm;
603 	long rss;
604 
605 	schedulerclock(NULL);	/* mpsafe */
606 	if ((p = curproc) != NULL) {
607 		/* Update resource usage integrals and maximums. */
608 		if ((pstats = p->p_stats) != NULL &&
609 		    (ru = &pstats->p_ru) != NULL &&
610 		    (vm = p->p_vmspace) != NULL) {
611 			ru->ru_ixrss += pgtok(vm->vm_tsize);
612 			ru->ru_idrss += pgtok(vm->vm_dsize);
613 			ru->ru_isrss += pgtok(vm->vm_ssize);
614 			rss = pgtok(vmspace_resident_count(vm));
615 			if (ru->ru_maxrss < rss)
616 				ru->ru_maxrss = rss;
617 		}
618 	}
619 }
620 
621 /*
622  * Compute number of ticks for the specified amount of time.  The
623  * return value is intended to be used in a clock interrupt timed
624  * operation and guarenteed to meet or exceed the requested time.
625  * If the representation overflows, return INT_MAX.  The minimum return
626  * value is 1 ticks and the function will average the calculation up.
627  * If any value greater then 0 microseconds is supplied, a value
628  * of at least 2 will be returned to ensure that a near-term clock
629  * interrupt does not cause the timeout to occur (degenerately) early.
630  *
631  * Note that limit checks must take into account microseconds, which is
632  * done simply by using the smaller signed long maximum instead of
633  * the unsigned long maximum.
634  *
635  * If ints have 32 bits, then the maximum value for any timeout in
636  * 10ms ticks is 248 days.
637  */
638 int
639 tvtohz_high(struct timeval *tv)
640 {
641 	int ticks;
642 	long sec, usec;
643 
644 	sec = tv->tv_sec;
645 	usec = tv->tv_usec;
646 	if (usec < 0) {
647 		sec--;
648 		usec += 1000000;
649 	}
650 	if (sec < 0) {
651 #ifdef DIAGNOSTIC
652 		if (usec > 0) {
653 			sec++;
654 			usec -= 1000000;
655 		}
656 		printf("tvotohz: negative time difference %ld sec %ld usec\n",
657 		       sec, usec);
658 #endif
659 		ticks = 1;
660 	} else if (sec <= INT_MAX / hz) {
661 		ticks = (int)(sec * hz +
662 			    ((u_long)usec + (tick - 1)) / tick) + 1;
663 	} else {
664 		ticks = INT_MAX;
665 	}
666 	return (ticks);
667 }
668 
669 /*
670  * Compute number of ticks for the specified amount of time, erroring on
671  * the side of it being too low to ensure that sleeping the returned number
672  * of ticks will not result in a late return.
673  *
674  * The supplied timeval may not be negative and should be normalized.  A
675  * return value of 0 is possible if the timeval converts to less then
676  * 1 tick.
677  *
678  * If ints have 32 bits, then the maximum value for any timeout in
679  * 10ms ticks is 248 days.
680  */
681 int
682 tvtohz_low(struct timeval *tv)
683 {
684 	int ticks;
685 	long sec;
686 
687 	sec = tv->tv_sec;
688 	if (sec <= INT_MAX / hz)
689 		ticks = (int)(sec * hz + (u_long)tv->tv_usec / tick);
690 	else
691 		ticks = INT_MAX;
692 	return (ticks);
693 }
694 
695 
696 /*
697  * Start profiling on a process.
698  *
699  * Kernel profiling passes proc0 which never exits and hence
700  * keeps the profile clock running constantly.
701  */
702 void
703 startprofclock(struct proc *p)
704 {
705 	if ((p->p_flag & P_PROFIL) == 0) {
706 		p->p_flag |= P_PROFIL;
707 #if 0	/* XXX */
708 		if (++profprocs == 1 && stathz != 0) {
709 			s = splstatclock();
710 			psdiv = psratio;
711 			setstatclockrate(profhz);
712 			splx(s);
713 		}
714 #endif
715 	}
716 }
717 
718 /*
719  * Stop profiling on a process.
720  */
721 void
722 stopprofclock(struct proc *p)
723 {
724 	if (p->p_flag & P_PROFIL) {
725 		p->p_flag &= ~P_PROFIL;
726 #if 0	/* XXX */
727 		if (--profprocs == 0 && stathz != 0) {
728 			s = splstatclock();
729 			psdiv = 1;
730 			setstatclockrate(stathz);
731 			splx(s);
732 		}
733 #endif
734 	}
735 }
736 
737 /*
738  * Return information about system clocks.
739  */
740 static int
741 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
742 {
743 	struct kinfo_clockinfo clkinfo;
744 	/*
745 	 * Construct clockinfo structure.
746 	 */
747 	clkinfo.ci_hz = hz;
748 	clkinfo.ci_tick = tick;
749 	clkinfo.ci_tickadj = ntp_default_tick_delta / 1000;
750 	clkinfo.ci_profhz = profhz;
751 	clkinfo.ci_stathz = stathz ? stathz : hz;
752 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
753 }
754 
755 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
756 	0, 0, sysctl_kern_clockrate, "S,clockinfo","");
757 
758 /*
759  * We have eight functions for looking at the clock, four for
760  * microseconds and four for nanoseconds.  For each there is fast
761  * but less precise version "get{nano|micro}[up]time" which will
762  * return a time which is up to 1/HZ previous to the call, whereas
763  * the raw version "{nano|micro}[up]time" will return a timestamp
764  * which is as precise as possible.  The "up" variants return the
765  * time relative to system boot, these are well suited for time
766  * interval measurements.
767  *
768  * Each cpu independantly maintains the current time of day, so all
769  * we need to do to protect ourselves from changes is to do a loop
770  * check on the seconds field changing out from under us.
771  *
772  * The system timer maintains a 32 bit count and due to various issues
773  * it is possible for the calculated delta to occassionally exceed
774  * cputimer_freq.  If this occurs the cputimer_freq64_nsec multiplication
775  * can easily overflow, so we deal with the case.  For uniformity we deal
776  * with the case in the usec case too.
777  */
778 void
779 getmicrouptime(struct timeval *tvp)
780 {
781 	struct globaldata *gd = mycpu;
782 	sysclock_t delta;
783 
784 	do {
785 		tvp->tv_sec = gd->gd_time_seconds;
786 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
787 	} while (tvp->tv_sec != gd->gd_time_seconds);
788 
789 	if (delta >= cputimer_freq) {
790 		tvp->tv_sec += delta / cputimer_freq;
791 		delta %= cputimer_freq;
792 	}
793 	tvp->tv_usec = (cputimer_freq64_usec * delta) >> 32;
794 	if (tvp->tv_usec >= 1000000) {
795 		tvp->tv_usec -= 1000000;
796 		++tvp->tv_sec;
797 	}
798 }
799 
800 void
801 getnanouptime(struct timespec *tsp)
802 {
803 	struct globaldata *gd = mycpu;
804 	sysclock_t delta;
805 
806 	do {
807 		tsp->tv_sec = gd->gd_time_seconds;
808 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
809 	} while (tsp->tv_sec != gd->gd_time_seconds);
810 
811 	if (delta >= cputimer_freq) {
812 		tsp->tv_sec += delta / cputimer_freq;
813 		delta %= cputimer_freq;
814 	}
815 	tsp->tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
816 }
817 
818 void
819 microuptime(struct timeval *tvp)
820 {
821 	struct globaldata *gd = mycpu;
822 	sysclock_t delta;
823 
824 	do {
825 		tvp->tv_sec = gd->gd_time_seconds;
826 		delta = cputimer_count() - gd->gd_cpuclock_base;
827 	} while (tvp->tv_sec != gd->gd_time_seconds);
828 
829 	if (delta >= cputimer_freq) {
830 		tvp->tv_sec += delta / cputimer_freq;
831 		delta %= cputimer_freq;
832 	}
833 	tvp->tv_usec = (cputimer_freq64_usec * delta) >> 32;
834 }
835 
836 void
837 nanouptime(struct timespec *tsp)
838 {
839 	struct globaldata *gd = mycpu;
840 	sysclock_t delta;
841 
842 	do {
843 		tsp->tv_sec = gd->gd_time_seconds;
844 		delta = cputimer_count() - gd->gd_cpuclock_base;
845 	} while (tsp->tv_sec != gd->gd_time_seconds);
846 
847 	if (delta >= cputimer_freq) {
848 		tsp->tv_sec += delta / cputimer_freq;
849 		delta %= cputimer_freq;
850 	}
851 	tsp->tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
852 }
853 
854 /*
855  * realtime routines
856  */
857 
858 void
859 getmicrotime(struct timeval *tvp)
860 {
861 	struct globaldata *gd = mycpu;
862 	struct timespec *bt;
863 	sysclock_t delta;
864 
865 	do {
866 		tvp->tv_sec = gd->gd_time_seconds;
867 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
868 	} while (tvp->tv_sec != gd->gd_time_seconds);
869 
870 	if (delta >= cputimer_freq) {
871 		tvp->tv_sec += delta / cputimer_freq;
872 		delta %= cputimer_freq;
873 	}
874 	tvp->tv_usec = (cputimer_freq64_usec * delta) >> 32;
875 
876 	bt = &basetime[basetime_index];
877 	tvp->tv_sec += bt->tv_sec;
878 	tvp->tv_usec += bt->tv_nsec / 1000;
879 	while (tvp->tv_usec >= 1000000) {
880 		tvp->tv_usec -= 1000000;
881 		++tvp->tv_sec;
882 	}
883 }
884 
885 void
886 getnanotime(struct timespec *tsp)
887 {
888 	struct globaldata *gd = mycpu;
889 	struct timespec *bt;
890 	sysclock_t delta;
891 
892 	do {
893 		tsp->tv_sec = gd->gd_time_seconds;
894 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
895 	} while (tsp->tv_sec != gd->gd_time_seconds);
896 
897 	if (delta >= cputimer_freq) {
898 		tsp->tv_sec += delta / cputimer_freq;
899 		delta %= cputimer_freq;
900 	}
901 	tsp->tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
902 
903 	bt = &basetime[basetime_index];
904 	tsp->tv_sec += bt->tv_sec;
905 	tsp->tv_nsec += bt->tv_nsec;
906 	while (tsp->tv_nsec >= 1000000000) {
907 		tsp->tv_nsec -= 1000000000;
908 		++tsp->tv_sec;
909 	}
910 }
911 
912 static void
913 getnanotime_nbt(struct timespec *nbt, struct timespec *tsp)
914 {
915 	struct globaldata *gd = mycpu;
916 	sysclock_t delta;
917 
918 	do {
919 		tsp->tv_sec = gd->gd_time_seconds;
920 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
921 	} while (tsp->tv_sec != gd->gd_time_seconds);
922 
923 	if (delta >= cputimer_freq) {
924 		tsp->tv_sec += delta / cputimer_freq;
925 		delta %= cputimer_freq;
926 	}
927 	tsp->tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
928 
929 	tsp->tv_sec += nbt->tv_sec;
930 	tsp->tv_nsec += nbt->tv_nsec;
931 	while (tsp->tv_nsec >= 1000000000) {
932 		tsp->tv_nsec -= 1000000000;
933 		++tsp->tv_sec;
934 	}
935 }
936 
937 
938 void
939 microtime(struct timeval *tvp)
940 {
941 	struct globaldata *gd = mycpu;
942 	struct timespec *bt;
943 	sysclock_t delta;
944 
945 	do {
946 		tvp->tv_sec = gd->gd_time_seconds;
947 		delta = cputimer_count() - gd->gd_cpuclock_base;
948 	} while (tvp->tv_sec != gd->gd_time_seconds);
949 
950 	if (delta >= cputimer_freq) {
951 		tvp->tv_sec += delta / cputimer_freq;
952 		delta %= cputimer_freq;
953 	}
954 	tvp->tv_usec = (cputimer_freq64_usec * delta) >> 32;
955 
956 	bt = &basetime[basetime_index];
957 	tvp->tv_sec += bt->tv_sec;
958 	tvp->tv_usec += bt->tv_nsec / 1000;
959 	while (tvp->tv_usec >= 1000000) {
960 		tvp->tv_usec -= 1000000;
961 		++tvp->tv_sec;
962 	}
963 }
964 
965 void
966 nanotime(struct timespec *tsp)
967 {
968 	struct globaldata *gd = mycpu;
969 	struct timespec *bt;
970 	sysclock_t delta;
971 
972 	do {
973 		tsp->tv_sec = gd->gd_time_seconds;
974 		delta = cputimer_count() - gd->gd_cpuclock_base;
975 	} while (tsp->tv_sec != gd->gd_time_seconds);
976 
977 	if (delta >= cputimer_freq) {
978 		tsp->tv_sec += delta / cputimer_freq;
979 		delta %= cputimer_freq;
980 	}
981 	tsp->tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
982 
983 	bt = &basetime[basetime_index];
984 	tsp->tv_sec += bt->tv_sec;
985 	tsp->tv_nsec += bt->tv_nsec;
986 	while (tsp->tv_nsec >= 1000000000) {
987 		tsp->tv_nsec -= 1000000000;
988 		++tsp->tv_sec;
989 	}
990 }
991 
992 /*
993  * note: this is not exactly synchronized with real time.  To do that we
994  * would have to do what microtime does and check for a nanoseconds overflow.
995  */
996 time_t
997 get_approximate_time_t(void)
998 {
999 	struct globaldata *gd = mycpu;
1000 	struct timespec *bt;
1001 
1002 	bt = &basetime[basetime_index];
1003 	return(gd->gd_time_seconds + bt->tv_sec);
1004 }
1005 
1006 int
1007 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1008 {
1009 	pps_params_t *app;
1010 	struct pps_fetch_args *fapi;
1011 #ifdef PPS_SYNC
1012 	struct pps_kcbind_args *kapi;
1013 #endif
1014 
1015 	switch (cmd) {
1016 	case PPS_IOC_CREATE:
1017 		return (0);
1018 	case PPS_IOC_DESTROY:
1019 		return (0);
1020 	case PPS_IOC_SETPARAMS:
1021 		app = (pps_params_t *)data;
1022 		if (app->mode & ~pps->ppscap)
1023 			return (EINVAL);
1024 		pps->ppsparam = *app;
1025 		return (0);
1026 	case PPS_IOC_GETPARAMS:
1027 		app = (pps_params_t *)data;
1028 		*app = pps->ppsparam;
1029 		app->api_version = PPS_API_VERS_1;
1030 		return (0);
1031 	case PPS_IOC_GETCAP:
1032 		*(int*)data = pps->ppscap;
1033 		return (0);
1034 	case PPS_IOC_FETCH:
1035 		fapi = (struct pps_fetch_args *)data;
1036 		if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1037 			return (EINVAL);
1038 		if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
1039 			return (EOPNOTSUPP);
1040 		pps->ppsinfo.current_mode = pps->ppsparam.mode;
1041 		fapi->pps_info_buf = pps->ppsinfo;
1042 		return (0);
1043 	case PPS_IOC_KCBIND:
1044 #ifdef PPS_SYNC
1045 		kapi = (struct pps_kcbind_args *)data;
1046 		/* XXX Only root should be able to do this */
1047 		if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1048 			return (EINVAL);
1049 		if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1050 			return (EINVAL);
1051 		if (kapi->edge & ~pps->ppscap)
1052 			return (EINVAL);
1053 		pps->kcmode = kapi->edge;
1054 		return (0);
1055 #else
1056 		return (EOPNOTSUPP);
1057 #endif
1058 	default:
1059 		return (ENOTTY);
1060 	}
1061 }
1062 
1063 void
1064 pps_init(struct pps_state *pps)
1065 {
1066 	pps->ppscap |= PPS_TSFMT_TSPEC;
1067 	if (pps->ppscap & PPS_CAPTUREASSERT)
1068 		pps->ppscap |= PPS_OFFSETASSERT;
1069 	if (pps->ppscap & PPS_CAPTURECLEAR)
1070 		pps->ppscap |= PPS_OFFSETCLEAR;
1071 }
1072 
1073 void
1074 pps_event(struct pps_state *pps, sysclock_t count, int event)
1075 {
1076 	struct globaldata *gd;
1077 	struct timespec *tsp;
1078 	struct timespec *osp;
1079 	struct timespec *bt;
1080 	struct timespec ts;
1081 	sysclock_t *pcount;
1082 #ifdef PPS_SYNC
1083 	sysclock_t tcount;
1084 #endif
1085 	sysclock_t delta;
1086 	pps_seq_t *pseq;
1087 	int foff;
1088 	int fhard;
1089 
1090 	gd = mycpu;
1091 
1092 	/* Things would be easier with arrays... */
1093 	if (event == PPS_CAPTUREASSERT) {
1094 		tsp = &pps->ppsinfo.assert_timestamp;
1095 		osp = &pps->ppsparam.assert_offset;
1096 		foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1097 		fhard = pps->kcmode & PPS_CAPTUREASSERT;
1098 		pcount = &pps->ppscount[0];
1099 		pseq = &pps->ppsinfo.assert_sequence;
1100 	} else {
1101 		tsp = &pps->ppsinfo.clear_timestamp;
1102 		osp = &pps->ppsparam.clear_offset;
1103 		foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1104 		fhard = pps->kcmode & PPS_CAPTURECLEAR;
1105 		pcount = &pps->ppscount[1];
1106 		pseq = &pps->ppsinfo.clear_sequence;
1107 	}
1108 
1109 	/* Nothing really happened */
1110 	if (*pcount == count)
1111 		return;
1112 
1113 	*pcount = count;
1114 
1115 	do {
1116 		ts.tv_sec = gd->gd_time_seconds;
1117 		delta = count - gd->gd_cpuclock_base;
1118 	} while (ts.tv_sec != gd->gd_time_seconds);
1119 
1120 	if (delta >= cputimer_freq) {
1121 		ts.tv_sec += delta / cputimer_freq;
1122 		delta %= cputimer_freq;
1123 	}
1124 	ts.tv_nsec = (cputimer_freq64_nsec * delta) >> 32;
1125 	bt = &basetime[basetime_index];
1126 	ts.tv_sec += bt->tv_sec;
1127 	ts.tv_nsec += bt->tv_nsec;
1128 	while (ts.tv_nsec >= 1000000000) {
1129 		ts.tv_nsec -= 1000000000;
1130 		++ts.tv_sec;
1131 	}
1132 
1133 	(*pseq)++;
1134 	*tsp = ts;
1135 
1136 	if (foff) {
1137 		timespecadd(tsp, osp);
1138 		if (tsp->tv_nsec < 0) {
1139 			tsp->tv_nsec += 1000000000;
1140 			tsp->tv_sec -= 1;
1141 		}
1142 	}
1143 #ifdef PPS_SYNC
1144 	if (fhard) {
1145 		/* magic, at its best... */
1146 		tcount = count - pps->ppscount[2];
1147 		pps->ppscount[2] = count;
1148 		if (tcount >= cputimer_freq) {
1149 			delta = (1000000000 * (tcount / cputimer_freq) +
1150 				 cputimer_freq64_nsec *
1151 				 (tcount % cputimer_freq)) >> 32;
1152 		} else {
1153 			delta = (cputimer_freq64_nsec * tcount) >> 32;
1154 		}
1155 		hardpps(tsp, delta);
1156 	}
1157 #endif
1158 }
1159 
1160