2 * SPDX-License-Identifier: Beerware
4 * ----------------------------------------------------------------------------
5 * "THE BEER-WARE LICENSE" (Revision 42):
6 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
7 * can do whatever you want with this stuff. If we meet some day, and you think
8 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
9 * ----------------------------------------------------------------------------
11 * Copyright (c) 2011, 2015, 2016 The FreeBSD Foundation
12 * All rights reserved.
14 * Portions of this software were developed by Julien Ridoux at the University
15 * of Melbourne under sponsorship from the FreeBSD Foundation.
17 * Portions of this software were developed by Konstantin Belousov
18 * under sponsorship from the FreeBSD Foundation.
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
25 #include "opt_ffclock.h"
27 #include <sys/param.h>
28 #include <sys/kernel.h>
29 #include <sys/limits.h>
31 #include <sys/mutex.h>
34 #include <sys/sleepqueue.h>
35 #include <sys/sysctl.h>
36 #include <sys/syslog.h>
37 #include <sys/systm.h>
38 #include <sys/timeffc.h>
39 #include <sys/timepps.h>
40 #include <sys/timetc.h>
41 #include <sys/timex.h>
45 * A large step happens on boot. This constant detects such steps.
46 * It is relatively small so that ntp_update_second gets called enough
47 * in the typical 'missed a couple of seconds' case, but doesn't loop
48 * forever when the time step is large.
50 #define LARGE_STEP 200
53 * Implement a dummy timecounter which we can use until we get a real one
54 * in the air. This allows the console and other early stuff to use
59 dummy_get_timecount(struct timecounter *tc)
66 static struct timecounter dummy_timecounter = {
67 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
71 /* These fields must be initialized by the driver. */
72 struct timecounter *th_counter;
73 int64_t th_adjustment;
76 u_int th_offset_count;
77 struct bintime th_offset;
78 struct bintime th_bintime;
79 struct timeval th_microtime;
80 struct timespec th_nanotime;
81 struct bintime th_boottime;
82 /* Fields not to be copied in tc_windup start with th_generation. */
84 struct timehands *th_next;
87 static struct timehands ths[16] = {
89 .th_counter = &dummy_timecounter,
90 .th_scale = (uint64_t)-1 / 1000000,
91 .th_large_delta = 1000000,
92 .th_offset = { .sec = 1 },
97 static struct timehands *volatile timehands = &ths[0];
98 struct timecounter *timecounter = &dummy_timecounter;
99 static struct timecounter *timecounters = &dummy_timecounter;
101 /* Mutex to protect the timecounter list. */
102 static struct mtx tc_lock;
104 int tc_min_ticktock_freq = 1;
106 volatile time_t time_second = 1;
107 volatile time_t time_uptime = 1;
109 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
110 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime,
111 CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
112 sysctl_kern_boottime, "S,timeval",
115 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
117 static SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc,
118 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
121 static int timestepwarnings;
122 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RWTUN,
123 ×tepwarnings, 0, "Log time steps");
125 static int timehands_count = 2;
126 SYSCTL_INT(_kern_timecounter, OID_AUTO, timehands_count,
127 CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
128 &timehands_count, 0, "Count of timehands in rotation");
130 struct bintime bt_timethreshold;
131 struct bintime bt_tickthreshold;
132 sbintime_t sbt_timethreshold;
133 sbintime_t sbt_tickthreshold;
134 struct bintime tc_tick_bt;
135 sbintime_t tc_tick_sbt;
137 int tc_timepercentage = TC_DEFAULTPERC;
138 static int sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS);
139 SYSCTL_PROC(_kern_timecounter, OID_AUTO, alloweddeviation,
140 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, 0,
141 sysctl_kern_timecounter_adjprecision, "I",
142 "Allowed time interval deviation in percents");
144 volatile int rtc_generation = 1;
146 static int tc_chosen; /* Non-zero if a specific tc was chosen via sysctl. */
147 static char tc_from_tunable[16];
149 static void tc_windup(struct bintime *new_boottimebin);
150 static void cpu_tick_calibrate(int);
152 void dtrace_getnanotime(struct timespec *tsp);
153 void dtrace_getnanouptime(struct timespec *tsp);
156 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
158 struct timeval boottime;
160 getboottime(&boottime);
162 /* i386 is the only arch which uses a 32bits time_t */
167 if (req->flags & SCTL_MASK32) {
168 tv[0] = boottime.tv_sec;
169 tv[1] = boottime.tv_usec;
170 return (SYSCTL_OUT(req, tv, sizeof(tv)));
174 return (SYSCTL_OUT(req, &boottime, sizeof(boottime)));
178 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
181 struct timecounter *tc = arg1;
183 ncount = tc->tc_get_timecount(tc);
184 return (sysctl_handle_int(oidp, &ncount, 0, req));
188 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
191 struct timecounter *tc = arg1;
193 freq = tc->tc_frequency;
194 return (sysctl_handle_64(oidp, &freq, 0, req));
198 * Return the difference between the timehands' counter value now and what
199 * was when we copied it to the timehands' offset_count.
201 static __inline u_int
202 tc_delta(struct timehands *th)
204 struct timecounter *tc;
207 return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
208 tc->tc_counter_mask);
212 bintime_add_tc_delta(struct bintime *bt, uint64_t scale,
213 uint64_t large_delta, uint64_t delta)
217 if (__predict_false(delta >= large_delta)) {
218 /* Avoid overflow for scale * delta. */
219 x = (scale >> 32) * delta;
221 bintime_addx(bt, x << 32);
222 bintime_addx(bt, (scale & 0xffffffff) * delta);
224 bintime_addx(bt, scale * delta);
229 * Functions for reading the time. We have to loop until we are sure that
230 * the timehands that we operated on was not updated under our feet. See
231 * the comment in <sys/time.h> for a description of these 12 functions.
235 bintime_off(struct bintime *bt, u_int off)
237 struct timehands *th;
240 u_int delta, gen, large_delta;
244 gen = atomic_load_acq_int(&th->th_generation);
245 btp = (struct bintime *)((vm_offset_t)th + off);
247 scale = th->th_scale;
248 delta = tc_delta(th);
249 large_delta = th->th_large_delta;
250 atomic_thread_fence_acq();
251 } while (gen == 0 || gen != th->th_generation);
253 bintime_add_tc_delta(bt, scale, large_delta, delta);
255 #define GETTHBINTIME(dst, member) \
257 _Static_assert(_Generic(((struct timehands *)NULL)->member, \
258 struct bintime: 1, default: 0) == 1, \
259 "struct timehands member is not of struct bintime type"); \
260 bintime_off(dst, __offsetof(struct timehands, member)); \
264 getthmember(void *out, size_t out_size, u_int off)
266 struct timehands *th;
271 gen = atomic_load_acq_int(&th->th_generation);
272 memcpy(out, (char *)th + off, out_size);
273 atomic_thread_fence_acq();
274 } while (gen == 0 || gen != th->th_generation);
276 #define GETTHMEMBER(dst, member) \
278 _Static_assert(_Generic(*dst, \
279 __typeof(((struct timehands *)NULL)->member): 1, \
281 "*dst and struct timehands member have different types"); \
282 getthmember(dst, sizeof(*dst), __offsetof(struct timehands, \
288 fbclock_binuptime(struct bintime *bt)
291 GETTHBINTIME(bt, th_offset);
295 fbclock_nanouptime(struct timespec *tsp)
299 fbclock_binuptime(&bt);
300 bintime2timespec(&bt, tsp);
304 fbclock_microuptime(struct timeval *tvp)
308 fbclock_binuptime(&bt);
309 bintime2timeval(&bt, tvp);
313 fbclock_bintime(struct bintime *bt)
316 GETTHBINTIME(bt, th_bintime);
320 fbclock_nanotime(struct timespec *tsp)
324 fbclock_bintime(&bt);
325 bintime2timespec(&bt, tsp);
329 fbclock_microtime(struct timeval *tvp)
333 fbclock_bintime(&bt);
334 bintime2timeval(&bt, tvp);
338 fbclock_getbinuptime(struct bintime *bt)
341 GETTHMEMBER(bt, th_offset);
345 fbclock_getnanouptime(struct timespec *tsp)
349 GETTHMEMBER(&bt, th_offset);
350 bintime2timespec(&bt, tsp);
354 fbclock_getmicrouptime(struct timeval *tvp)
358 GETTHMEMBER(&bt, th_offset);
359 bintime2timeval(&bt, tvp);
363 fbclock_getbintime(struct bintime *bt)
366 GETTHMEMBER(bt, th_bintime);
370 fbclock_getnanotime(struct timespec *tsp)
373 GETTHMEMBER(tsp, th_nanotime);
377 fbclock_getmicrotime(struct timeval *tvp)
380 GETTHMEMBER(tvp, th_microtime);
385 binuptime(struct bintime *bt)
388 GETTHBINTIME(bt, th_offset);
392 nanouptime(struct timespec *tsp)
397 bintime2timespec(&bt, tsp);
401 microuptime(struct timeval *tvp)
406 bintime2timeval(&bt, tvp);
410 bintime(struct bintime *bt)
413 GETTHBINTIME(bt, th_bintime);
417 nanotime(struct timespec *tsp)
422 bintime2timespec(&bt, tsp);
426 microtime(struct timeval *tvp)
431 bintime2timeval(&bt, tvp);
435 getbinuptime(struct bintime *bt)
438 GETTHMEMBER(bt, th_offset);
442 getnanouptime(struct timespec *tsp)
446 GETTHMEMBER(&bt, th_offset);
447 bintime2timespec(&bt, tsp);
451 getmicrouptime(struct timeval *tvp)
455 GETTHMEMBER(&bt, th_offset);
456 bintime2timeval(&bt, tvp);
460 getbintime(struct bintime *bt)
463 GETTHMEMBER(bt, th_bintime);
467 getnanotime(struct timespec *tsp)
470 GETTHMEMBER(tsp, th_nanotime);
474 getmicrotime(struct timeval *tvp)
477 GETTHMEMBER(tvp, th_microtime);
482 getboottime(struct timeval *boottime)
484 struct bintime boottimebin;
486 getboottimebin(&boottimebin);
487 bintime2timeval(&boottimebin, boottime);
491 getboottimebin(struct bintime *boottimebin)
494 GETTHMEMBER(boottimebin, th_boottime);
499 * Support for feed-forward synchronization algorithms. This is heavily inspired
500 * by the timehands mechanism but kept independent from it. *_windup() functions
501 * have some connection to avoid accessing the timecounter hardware more than
505 /* Feed-forward clock estimates kept updated by the synchronization daemon. */
506 struct ffclock_estimate ffclock_estimate;
507 struct bintime ffclock_boottime; /* Feed-forward boot time estimate. */
508 uint32_t ffclock_status; /* Feed-forward clock status. */
509 int8_t ffclock_updated; /* New estimates are available. */
510 struct mtx ffclock_mtx; /* Mutex on ffclock_estimate. */
513 struct ffclock_estimate cest;
514 struct bintime tick_time;
515 struct bintime tick_time_lerp;
516 ffcounter tick_ffcount;
517 uint64_t period_lerp;
518 volatile uint8_t gen;
519 struct fftimehands *next;
522 #define NUM_ELEMENTS(x) (sizeof(x) / sizeof(*x))
524 static struct fftimehands ffth[10];
525 static struct fftimehands *volatile fftimehands = ffth;
530 struct fftimehands *cur;
531 struct fftimehands *last;
533 memset(ffth, 0, sizeof(ffth));
535 last = ffth + NUM_ELEMENTS(ffth) - 1;
536 for (cur = ffth; cur < last; cur++)
541 ffclock_status = FFCLOCK_STA_UNSYNC;
542 mtx_init(&ffclock_mtx, "ffclock lock", NULL, MTX_DEF);
546 * Reset the feed-forward clock estimates. Called from inittodr() to get things
547 * kick started and uses the timecounter nominal frequency as a first period
548 * estimate. Note: this function may be called several time just after boot.
549 * Note: this is the only function that sets the value of boot time for the
550 * monotonic (i.e. uptime) version of the feed-forward clock.
553 ffclock_reset_clock(struct timespec *ts)
555 struct timecounter *tc;
556 struct ffclock_estimate cest;
558 tc = timehands->th_counter;
559 memset(&cest, 0, sizeof(struct ffclock_estimate));
561 timespec2bintime(ts, &ffclock_boottime);
562 timespec2bintime(ts, &(cest.update_time));
563 ffclock_read_counter(&cest.update_ffcount);
564 cest.leapsec_next = 0;
565 cest.period = ((1ULL << 63) / tc->tc_frequency) << 1;
568 cest.status = FFCLOCK_STA_UNSYNC;
569 cest.leapsec_total = 0;
572 mtx_lock(&ffclock_mtx);
573 bcopy(&cest, &ffclock_estimate, sizeof(struct ffclock_estimate));
574 ffclock_updated = INT8_MAX;
575 mtx_unlock(&ffclock_mtx);
577 printf("ffclock reset: %s (%llu Hz), time = %ld.%09lu\n", tc->tc_name,
578 (unsigned long long)tc->tc_frequency, (long)ts->tv_sec,
579 (unsigned long)ts->tv_nsec);
583 * Sub-routine to convert a time interval measured in RAW counter units to time
584 * in seconds stored in bintime format.
585 * NOTE: bintime_mul requires u_int, but the value of the ffcounter may be
586 * larger than the max value of u_int (on 32 bit architecture). Loop to consume
590 ffclock_convert_delta(ffcounter ffdelta, uint64_t period, struct bintime *bt)
593 ffcounter delta, delta_max;
595 delta_max = (1ULL << (8 * sizeof(unsigned int))) - 1;
598 if (ffdelta > delta_max)
604 bintime_mul(&bt2, (unsigned int)delta);
605 bintime_add(bt, &bt2);
607 } while (ffdelta > 0);
611 * Update the fftimehands.
612 * Push the tick ffcount and time(s) forward based on current clock estimate.
613 * The conversion from ffcounter to bintime relies on the difference clock
614 * principle, whose accuracy relies on computing small time intervals. If a new
615 * clock estimate has been passed by the synchronisation daemon, make it
616 * current, and compute the linear interpolation for monotonic time if needed.
619 ffclock_windup(unsigned int delta)
621 struct ffclock_estimate *cest;
622 struct fftimehands *ffth;
623 struct bintime bt, gap_lerp;
626 unsigned int polling;
627 uint8_t forward_jump, ogen;
630 * Pick the next timehand, copy current ffclock estimates and move tick
631 * times and counter forward.
634 ffth = fftimehands->next;
638 bcopy(&fftimehands->cest, cest, sizeof(struct ffclock_estimate));
639 ffdelta = (ffcounter)delta;
640 ffth->period_lerp = fftimehands->period_lerp;
642 ffth->tick_time = fftimehands->tick_time;
643 ffclock_convert_delta(ffdelta, cest->period, &bt);
644 bintime_add(&ffth->tick_time, &bt);
646 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
647 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt);
648 bintime_add(&ffth->tick_time_lerp, &bt);
650 ffth->tick_ffcount = fftimehands->tick_ffcount + ffdelta;
653 * Assess the status of the clock, if the last update is too old, it is
654 * likely the synchronisation daemon is dead and the clock is free
657 if (ffclock_updated == 0) {
658 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
659 ffclock_convert_delta(ffdelta, cest->period, &bt);
660 if (bt.sec > 2 * FFCLOCK_SKM_SCALE)
661 ffclock_status |= FFCLOCK_STA_UNSYNC;
665 * If available, grab updated clock estimates and make them current.
666 * Recompute time at this tick using the updated estimates. The clock
667 * estimates passed the feed-forward synchronisation daemon may result
668 * in time conversion that is not monotonically increasing (just after
669 * the update). time_lerp is a particular linear interpolation over the
670 * synchronisation algo polling period that ensures monotonicity for the
671 * clock ids requesting it.
673 if (ffclock_updated > 0) {
674 bcopy(&ffclock_estimate, cest, sizeof(struct ffclock_estimate));
675 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
676 ffth->tick_time = cest->update_time;
677 ffclock_convert_delta(ffdelta, cest->period, &bt);
678 bintime_add(&ffth->tick_time, &bt);
680 /* ffclock_reset sets ffclock_updated to INT8_MAX */
681 if (ffclock_updated == INT8_MAX)
682 ffth->tick_time_lerp = ffth->tick_time;
684 if (bintime_cmp(&ffth->tick_time, &ffth->tick_time_lerp, >))
689 bintime_clear(&gap_lerp);
691 gap_lerp = ffth->tick_time;
692 bintime_sub(&gap_lerp, &ffth->tick_time_lerp);
694 gap_lerp = ffth->tick_time_lerp;
695 bintime_sub(&gap_lerp, &ffth->tick_time);
699 * The reset from the RTC clock may be far from accurate, and
700 * reducing the gap between real time and interpolated time
701 * could take a very long time if the interpolated clock insists
702 * on strict monotonicity. The clock is reset under very strict
703 * conditions (kernel time is known to be wrong and
704 * synchronization daemon has been restarted recently.
705 * ffclock_boottime absorbs the jump to ensure boot time is
706 * correct and uptime functions stay consistent.
708 if (((ffclock_status & FFCLOCK_STA_UNSYNC) == FFCLOCK_STA_UNSYNC) &&
709 ((cest->status & FFCLOCK_STA_UNSYNC) == 0) &&
710 ((cest->status & FFCLOCK_STA_WARMUP) == FFCLOCK_STA_WARMUP)) {
712 bintime_add(&ffclock_boottime, &gap_lerp);
714 bintime_sub(&ffclock_boottime, &gap_lerp);
715 ffth->tick_time_lerp = ffth->tick_time;
716 bintime_clear(&gap_lerp);
719 ffclock_status = cest->status;
720 ffth->period_lerp = cest->period;
723 * Compute corrected period used for the linear interpolation of
724 * time. The rate of linear interpolation is capped to 5000PPM
727 if (bintime_isset(&gap_lerp)) {
728 ffdelta = cest->update_ffcount;
729 ffdelta -= fftimehands->cest.update_ffcount;
730 ffclock_convert_delta(ffdelta, cest->period, &bt);
733 bt.frac = 5000000 * (uint64_t)18446744073LL;
734 bintime_mul(&bt, polling);
735 if (bintime_cmp(&gap_lerp, &bt, >))
738 /* Approximate 1 sec by 1-(1/2^64) to ease arithmetic */
740 if (gap_lerp.sec > 0) {
742 frac /= ffdelta / gap_lerp.sec;
744 frac += gap_lerp.frac / ffdelta;
747 ffth->period_lerp += frac;
749 ffth->period_lerp -= frac;
761 * Adjust the fftimehands when the timecounter is changed. Stating the obvious,
762 * the old and new hardware counter cannot be read simultaneously. tc_windup()
763 * does read the two counters 'back to back', but a few cycles are effectively
764 * lost, and not accumulated in tick_ffcount. This is a fairly radical
765 * operation for a feed-forward synchronization daemon, and it is its job to not
766 * pushing irrelevant data to the kernel. Because there is no locking here,
767 * simply force to ignore pending or next update to give daemon a chance to
768 * realize the counter has changed.
771 ffclock_change_tc(struct timehands *th)
773 struct fftimehands *ffth;
774 struct ffclock_estimate *cest;
775 struct timecounter *tc;
779 ffth = fftimehands->next;
784 bcopy(&(fftimehands->cest), cest, sizeof(struct ffclock_estimate));
785 cest->period = ((1ULL << 63) / tc->tc_frequency ) << 1;
788 cest->status |= FFCLOCK_STA_UNSYNC;
790 ffth->tick_ffcount = fftimehands->tick_ffcount;
791 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
792 ffth->tick_time = fftimehands->tick_time;
793 ffth->period_lerp = cest->period;
795 /* Do not lock but ignore next update from synchronization daemon. */
805 * Retrieve feed-forward counter and time of last kernel tick.
808 ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags)
810 struct fftimehands *ffth;
814 * No locking but check generation has not changed. Also need to make
815 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
820 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP)
821 *bt = ffth->tick_time_lerp;
823 *bt = ffth->tick_time;
824 *ffcount = ffth->tick_ffcount;
825 } while (gen == 0 || gen != ffth->gen);
829 * Absolute clock conversion. Low level function to convert ffcounter to
830 * bintime. The ffcounter is converted using the current ffclock period estimate
831 * or the "interpolated period" to ensure monotonicity.
832 * NOTE: this conversion may have been deferred, and the clock updated since the
833 * hardware counter has been read.
836 ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags)
838 struct fftimehands *ffth;
844 * No locking but check generation has not changed. Also need to make
845 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
850 if (ffcount > ffth->tick_ffcount)
851 ffdelta = ffcount - ffth->tick_ffcount;
853 ffdelta = ffth->tick_ffcount - ffcount;
855 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) {
856 *bt = ffth->tick_time_lerp;
857 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt2);
859 *bt = ffth->tick_time;
860 ffclock_convert_delta(ffdelta, ffth->cest.period, &bt2);
863 if (ffcount > ffth->tick_ffcount)
864 bintime_add(bt, &bt2);
866 bintime_sub(bt, &bt2);
867 } while (gen == 0 || gen != ffth->gen);
871 * Difference clock conversion.
872 * Low level function to Convert a time interval measured in RAW counter units
873 * into bintime. The difference clock allows measuring small intervals much more
874 * reliably than the absolute clock.
877 ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt)
879 struct fftimehands *ffth;
882 /* No locking but check generation has not changed. */
886 ffclock_convert_delta(ffdelta, ffth->cest.period, bt);
887 } while (gen == 0 || gen != ffth->gen);
891 * Access to current ffcounter value.
894 ffclock_read_counter(ffcounter *ffcount)
896 struct timehands *th;
897 struct fftimehands *ffth;
898 unsigned int gen, delta;
901 * ffclock_windup() called from tc_windup(), safe to rely on
902 * th->th_generation only, for correct delta and ffcounter.
906 gen = atomic_load_acq_int(&th->th_generation);
908 delta = tc_delta(th);
909 *ffcount = ffth->tick_ffcount;
910 atomic_thread_fence_acq();
911 } while (gen == 0 || gen != th->th_generation);
917 binuptime(struct bintime *bt)
920 binuptime_fromclock(bt, sysclock_active);
924 nanouptime(struct timespec *tsp)
927 nanouptime_fromclock(tsp, sysclock_active);
931 microuptime(struct timeval *tvp)
934 microuptime_fromclock(tvp, sysclock_active);
938 bintime(struct bintime *bt)
941 bintime_fromclock(bt, sysclock_active);
945 nanotime(struct timespec *tsp)
948 nanotime_fromclock(tsp, sysclock_active);
952 microtime(struct timeval *tvp)
955 microtime_fromclock(tvp, sysclock_active);
959 getbinuptime(struct bintime *bt)
962 getbinuptime_fromclock(bt, sysclock_active);
966 getnanouptime(struct timespec *tsp)
969 getnanouptime_fromclock(tsp, sysclock_active);
973 getmicrouptime(struct timeval *tvp)
976 getmicrouptime_fromclock(tvp, sysclock_active);
980 getbintime(struct bintime *bt)
983 getbintime_fromclock(bt, sysclock_active);
987 getnanotime(struct timespec *tsp)
990 getnanotime_fromclock(tsp, sysclock_active);
994 getmicrotime(struct timeval *tvp)
997 getmicrouptime_fromclock(tvp, sysclock_active);
1000 #endif /* FFCLOCK */
1003 * This is a clone of getnanotime and used for walltimestamps.
1004 * The dtrace_ prefix prevents fbt from creating probes for
1005 * it so walltimestamp can be safely used in all fbt probes.
1008 dtrace_getnanotime(struct timespec *tsp)
1011 GETTHMEMBER(tsp, th_nanotime);
1015 * This is a clone of getnanouptime used for time since boot.
1016 * The dtrace_ prefix prevents fbt from creating probes for
1017 * it so an uptime that can be safely used in all fbt probes.
1020 dtrace_getnanouptime(struct timespec *tsp)
1024 GETTHMEMBER(&bt, th_offset);
1025 bintime2timespec(&bt, tsp);
1029 * System clock currently providing time to the system. Modifiable via sysctl
1030 * when the FFCLOCK option is defined.
1032 int sysclock_active = SYSCLOCK_FBCK;
1034 /* Internal NTP status and error estimates. */
1035 extern int time_status;
1036 extern long time_esterror;
1039 * Take a snapshot of sysclock data which can be used to compare system clocks
1040 * and generate timestamps after the fact.
1043 sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
1045 struct fbclock_info *fbi;
1046 struct timehands *th;
1048 unsigned int delta, gen;
1051 struct fftimehands *ffth;
1052 struct ffclock_info *ffi;
1053 struct ffclock_estimate cest;
1055 ffi = &clock_snap->ff_info;
1058 fbi = &clock_snap->fb_info;
1063 gen = atomic_load_acq_int(&th->th_generation);
1064 fbi->th_scale = th->th_scale;
1065 fbi->tick_time = th->th_offset;
1068 ffi->tick_time = ffth->tick_time_lerp;
1069 ffi->tick_time_lerp = ffth->tick_time_lerp;
1070 ffi->period = ffth->cest.period;
1071 ffi->period_lerp = ffth->period_lerp;
1072 clock_snap->ffcount = ffth->tick_ffcount;
1076 delta = tc_delta(th);
1077 atomic_thread_fence_acq();
1078 } while (gen == 0 || gen != th->th_generation);
1080 clock_snap->delta = delta;
1081 clock_snap->sysclock_active = sysclock_active;
1083 /* Record feedback clock status and error. */
1084 clock_snap->fb_info.status = time_status;
1085 /* XXX: Very crude estimate of feedback clock error. */
1086 bt.sec = time_esterror / 1000000;
1087 bt.frac = ((time_esterror - bt.sec) * 1000000) *
1088 (uint64_t)18446744073709ULL;
1089 clock_snap->fb_info.error = bt;
1093 clock_snap->ffcount += delta;
1095 /* Record feed-forward clock leap second adjustment. */
1096 ffi->leapsec_adjustment = cest.leapsec_total;
1097 if (clock_snap->ffcount > cest.leapsec_next)
1098 ffi->leapsec_adjustment -= cest.leapsec;
1100 /* Record feed-forward clock status and error. */
1101 clock_snap->ff_info.status = cest.status;
1102 ffcount = clock_snap->ffcount - cest.update_ffcount;
1103 ffclock_convert_delta(ffcount, cest.period, &bt);
1104 /* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s]. */
1105 bintime_mul(&bt, cest.errb_rate * (uint64_t)18446744073709ULL);
1106 /* 18446744073 = int(2^64 / 1e9), since err_abs in [ns]. */
1107 bintime_addx(&bt, cest.errb_abs * (uint64_t)18446744073ULL);
1108 clock_snap->ff_info.error = bt;
1113 * Convert a sysclock snapshot into a struct bintime based on the specified
1114 * clock source and flags.
1117 sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
1118 int whichclock, uint32_t flags)
1120 struct bintime boottimebin;
1126 switch (whichclock) {
1128 *bt = cs->fb_info.tick_time;
1130 /* If snapshot was created with !fast, delta will be >0. */
1132 bintime_addx(bt, cs->fb_info.th_scale * cs->delta);
1134 if ((flags & FBCLOCK_UPTIME) == 0) {
1135 getboottimebin(&boottimebin);
1136 bintime_add(bt, &boottimebin);
1141 if (flags & FFCLOCK_LERP) {
1142 *bt = cs->ff_info.tick_time_lerp;
1143 period = cs->ff_info.period_lerp;
1145 *bt = cs->ff_info.tick_time;
1146 period = cs->ff_info.period;
1149 /* If snapshot was created with !fast, delta will be >0. */
1150 if (cs->delta > 0) {
1151 ffclock_convert_delta(cs->delta, period, &bt2);
1152 bintime_add(bt, &bt2);
1155 /* Leap second adjustment. */
1156 if (flags & FFCLOCK_LEAPSEC)
1157 bt->sec -= cs->ff_info.leapsec_adjustment;
1159 /* Boot time adjustment, for uptime/monotonic clocks. */
1160 if (flags & FFCLOCK_UPTIME)
1161 bintime_sub(bt, &ffclock_boottime);
1173 * Initialize a new timecounter and possibly use it.
1176 tc_init(struct timecounter *tc)
1179 struct sysctl_oid *tc_root;
1181 u = tc->tc_frequency / tc->tc_counter_mask;
1182 /* XXX: We need some margin here, 10% is a guess */
1185 if (u > hz && tc->tc_quality >= 0) {
1186 tc->tc_quality = -2000;
1188 printf("Timecounter \"%s\" frequency %ju Hz",
1189 tc->tc_name, (uintmax_t)tc->tc_frequency);
1190 printf(" -- Insufficient hz, needs at least %u\n", u);
1192 } else if (tc->tc_quality >= 0 || bootverbose) {
1193 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
1194 tc->tc_name, (uintmax_t)tc->tc_frequency,
1199 * Set up sysctl tree for this counter.
1201 tc_root = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
1202 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
1203 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1204 "timecounter description", "timecounter");
1205 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1206 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
1207 "mask for implemented bits");
1208 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1209 "counter", CTLTYPE_UINT | CTLFLAG_RD | CTLFLAG_MPSAFE, tc,
1210 sizeof(*tc), sysctl_kern_timecounter_get, "IU",
1211 "current timecounter value");
1212 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1213 "frequency", CTLTYPE_U64 | CTLFLAG_RD | CTLFLAG_MPSAFE, tc,
1214 sizeof(*tc), sysctl_kern_timecounter_freq, "QU",
1215 "timecounter frequency");
1216 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1217 "quality", CTLFLAG_RD, &(tc->tc_quality), 0,
1218 "goodness of time counter");
1221 tc->tc_next = timecounters;
1225 * Do not automatically switch if the current tc was specifically
1226 * chosen. Never automatically use a timecounter with negative quality.
1227 * Even though we run on the dummy counter, switching here may be
1228 * worse since this timecounter may not be monotonic.
1232 if (tc->tc_quality < 0)
1234 if (tc_from_tunable[0] != '\0' &&
1235 strcmp(tc->tc_name, tc_from_tunable) == 0) {
1237 tc_from_tunable[0] = '\0';
1239 if (tc->tc_quality < timecounter->tc_quality)
1241 if (tc->tc_quality == timecounter->tc_quality &&
1242 tc->tc_frequency < timecounter->tc_frequency)
1245 (void)tc->tc_get_timecount(tc);
1248 mtx_unlock(&tc_lock);
1251 /* Report the frequency of the current timecounter. */
1253 tc_getfrequency(void)
1256 return (timehands->th_counter->tc_frequency);
1260 sleeping_on_old_rtc(struct thread *td)
1264 * td_rtcgen is modified by curthread when it is running,
1265 * and by other threads in this function. By finding the thread
1266 * on a sleepqueue and holding the lock on the sleepqueue
1267 * chain, we guarantee that the thread is not running and that
1268 * modifying td_rtcgen is safe. Setting td_rtcgen to zero informs
1269 * the thread that it was woken due to a real-time clock adjustment.
1270 * (The declaration of td_rtcgen refers to this comment.)
1272 if (td->td_rtcgen != 0 && td->td_rtcgen != rtc_generation) {
1279 static struct mtx tc_setclock_mtx;
1280 MTX_SYSINIT(tc_setclock_init, &tc_setclock_mtx, "tcsetc", MTX_SPIN);
1283 * Step our concept of UTC. This is done by modifying our estimate of
1287 tc_setclock(struct timespec *ts)
1289 struct timespec tbef, taft;
1290 struct bintime bt, bt2;
1292 timespec2bintime(ts, &bt);
1294 mtx_lock_spin(&tc_setclock_mtx);
1295 cpu_tick_calibrate(1);
1297 bintime_sub(&bt, &bt2);
1299 /* XXX fiddle all the little crinkly bits around the fiords... */
1301 mtx_unlock_spin(&tc_setclock_mtx);
1303 /* Avoid rtc_generation == 0, since td_rtcgen == 0 is special. */
1304 atomic_add_rel_int(&rtc_generation, 2);
1305 sleepq_chains_remove_matching(sleeping_on_old_rtc);
1306 if (timestepwarnings) {
1309 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
1310 (intmax_t)tbef.tv_sec, tbef.tv_nsec,
1311 (intmax_t)taft.tv_sec, taft.tv_nsec,
1312 (intmax_t)ts->tv_sec, ts->tv_nsec);
1317 * Recalculate the scaling factor. We want the number of 1/2^64
1318 * fractions of a second per period of the hardware counter, taking
1319 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
1320 * processing provides us with.
1322 * The th_adjustment is nanoseconds per second with 32 bit binary
1323 * fraction and we want 64 bit binary fraction of second:
1325 * x = a * 2^32 / 10^9 = a * 4.294967296
1327 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
1328 * we can only multiply by about 850 without overflowing, that
1329 * leaves no suitably precise fractions for multiply before divide.
1331 * Divide before multiply with a fraction of 2199/512 results in a
1332 * systematic undercompensation of 10PPM of th_adjustment. On a
1333 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
1335 * We happily sacrifice the lowest of the 64 bits of our result
1336 * to the goddess of code clarity.
1339 recalculate_scaling_factor_and_large_delta(struct timehands *th)
1343 scale = (uint64_t)1 << 63;
1344 scale += (th->th_adjustment / 1024) * 2199;
1345 scale /= th->th_counter->tc_frequency;
1346 th->th_scale = scale * 2;
1347 th->th_large_delta = MIN(((uint64_t)1 << 63) / scale, UINT_MAX);
1351 * Initialize the next struct timehands in the ring and make
1352 * it the active timehands. Along the way we might switch to a different
1353 * timecounter and/or do seconds processing in NTP. Slightly magic.
1356 tc_windup(struct bintime *new_boottimebin)
1359 struct timehands *th, *tho;
1360 u_int delta, ncount, ogen;
1365 * Make the next timehands a copy of the current one, but do
1366 * not overwrite the generation or next pointer. While we
1367 * update the contents, the generation must be zero. We need
1368 * to ensure that the zero generation is visible before the
1369 * data updates become visible, which requires release fence.
1370 * For similar reasons, re-reading of the generation after the
1371 * data is read should use acquire fence.
1375 ogen = th->th_generation;
1376 th->th_generation = 0;
1377 atomic_thread_fence_rel();
1378 memcpy(th, tho, offsetof(struct timehands, th_generation));
1379 if (new_boottimebin != NULL)
1380 th->th_boottime = *new_boottimebin;
1383 * Capture a timecounter delta on the current timecounter and if
1384 * changing timecounters, a counter value from the new timecounter.
1385 * Update the offset fields accordingly.
1387 delta = tc_delta(th);
1388 if (th->th_counter != timecounter)
1389 ncount = timecounter->tc_get_timecount(timecounter);
1393 ffclock_windup(delta);
1395 th->th_offset_count += delta;
1396 th->th_offset_count &= th->th_counter->tc_counter_mask;
1397 bintime_add_tc_delta(&th->th_offset, th->th_scale,
1398 th->th_large_delta, delta);
1401 * Hardware latching timecounters may not generate interrupts on
1402 * PPS events, so instead we poll them. There is a finite risk that
1403 * the hardware might capture a count which is later than the one we
1404 * got above, and therefore possibly in the next NTP second which might
1405 * have a different rate than the current NTP second. It doesn't
1406 * matter in practice.
1408 if (tho->th_counter->tc_poll_pps)
1409 tho->th_counter->tc_poll_pps(tho->th_counter);
1412 * Deal with NTP second processing. The loop normally
1413 * iterates at most once, but in extreme situations it might
1414 * keep NTP sane if timeouts are not run for several seconds.
1415 * At boot, the time step can be large when the TOD hardware
1416 * has been read, so on really large steps, we call
1417 * ntp_update_second only twice. We need to call it twice in
1418 * case we missed a leap second.
1421 bintime_add(&bt, &th->th_boottime);
1422 i = bt.sec - tho->th_microtime.tv_sec;
1429 ntp_update_second(&th->th_adjustment, &bt.sec);
1431 th->th_boottime.sec += bt.sec - t;
1435 recalculate_scaling_factor_and_large_delta(th);
1438 /* Update the UTC timestamps used by the get*() functions. */
1439 th->th_bintime = bt;
1440 bintime2timeval(&bt, &th->th_microtime);
1441 bintime2timespec(&bt, &th->th_nanotime);
1443 /* Now is a good time to change timecounters. */
1444 if (th->th_counter != timecounter) {
1446 if ((timecounter->tc_flags & TC_FLAGS_C2STOP) != 0)
1447 cpu_disable_c2_sleep++;
1448 if ((th->th_counter->tc_flags & TC_FLAGS_C2STOP) != 0)
1449 cpu_disable_c2_sleep--;
1451 th->th_counter = timecounter;
1452 th->th_offset_count = ncount;
1453 tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
1454 (((uint64_t)timecounter->tc_counter_mask + 1) / 3));
1455 recalculate_scaling_factor_and_large_delta(th);
1457 ffclock_change_tc(th);
1462 * Now that the struct timehands is again consistent, set the new
1463 * generation number, making sure to not make it zero.
1467 atomic_store_rel_int(&th->th_generation, ogen);
1469 /* Go live with the new struct timehands. */
1471 switch (sysclock_active) {
1474 time_second = th->th_microtime.tv_sec;
1475 time_uptime = th->th_offset.sec;
1479 time_second = fftimehands->tick_time_lerp.sec;
1480 time_uptime = fftimehands->tick_time_lerp.sec - ffclock_boottime.sec;
1486 timekeep_push_vdso();
1489 /* Report or change the active timecounter hardware. */
1491 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
1494 struct timecounter *newtc, *tc;
1499 strlcpy(newname, tc->tc_name, sizeof(newname));
1500 mtx_unlock(&tc_lock);
1502 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
1503 if (error != 0 || req->newptr == NULL)
1507 /* Record that the tc in use now was specifically chosen. */
1509 if (strcmp(newname, tc->tc_name) == 0) {
1510 mtx_unlock(&tc_lock);
1513 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
1514 if (strcmp(newname, newtc->tc_name) != 0)
1517 /* Warm up new timecounter. */
1518 (void)newtc->tc_get_timecount(newtc);
1520 timecounter = newtc;
1523 * The vdso timehands update is deferred until the next
1526 * This is prudent given that 'timekeep_push_vdso()' does not
1527 * use any locking and that it can be called in hard interrupt
1528 * context via 'tc_windup()'.
1532 mtx_unlock(&tc_lock);
1533 return (newtc != NULL ? 0 : EINVAL);
1535 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware,
1536 CTLTYPE_STRING | CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE, 0, 0,
1537 sysctl_kern_timecounter_hardware, "A",
1538 "Timecounter hardware selected");
1540 /* Report the available timecounter hardware. */
1542 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
1545 struct timecounter *tc;
1548 error = sysctl_wire_old_buffer(req, 0);
1551 sbuf_new_for_sysctl(&sb, NULL, 0, req);
1553 for (tc = timecounters; tc != NULL; tc = tc->tc_next) {
1554 if (tc != timecounters)
1555 sbuf_putc(&sb, ' ');
1556 sbuf_printf(&sb, "%s(%d)", tc->tc_name, tc->tc_quality);
1558 mtx_unlock(&tc_lock);
1559 error = sbuf_finish(&sb);
1564 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice,
1565 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
1566 sysctl_kern_timecounter_choice, "A",
1567 "Timecounter hardware detected");
1570 * RFC 2783 PPS-API implementation.
1574 * Return true if the driver is aware of the abi version extensions in the
1575 * pps_state structure, and it supports at least the given abi version number.
1578 abi_aware(struct pps_state *pps, int vers)
1581 return ((pps->kcmode & KCMODE_ABIFLAG) && pps->driver_abi >= vers);
1585 pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps)
1588 pps_seq_t aseq, cseq;
1591 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1595 * If no timeout is requested, immediately return whatever values were
1596 * most recently captured. If timeout seconds is -1, that's a request
1597 * to block without a timeout. WITNESS won't let us sleep forever
1598 * without a lock (we really don't need a lock), so just repeatedly
1599 * sleep a long time.
1601 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) {
1602 if (fapi->timeout.tv_sec == -1)
1605 tv.tv_sec = fapi->timeout.tv_sec;
1606 tv.tv_usec = fapi->timeout.tv_nsec / 1000;
1609 aseq = atomic_load_int(&pps->ppsinfo.assert_sequence);
1610 cseq = atomic_load_int(&pps->ppsinfo.clear_sequence);
1611 while (aseq == atomic_load_int(&pps->ppsinfo.assert_sequence) &&
1612 cseq == atomic_load_int(&pps->ppsinfo.clear_sequence)) {
1613 if (abi_aware(pps, 1) && pps->driver_mtx != NULL) {
1614 if (pps->flags & PPSFLAG_MTX_SPIN) {
1615 err = msleep_spin(pps, pps->driver_mtx,
1618 err = msleep(pps, pps->driver_mtx, PCATCH,
1622 err = tsleep(pps, PCATCH, "ppsfch", timo);
1624 if (err == EWOULDBLOCK) {
1625 if (fapi->timeout.tv_sec == -1) {
1630 } else if (err != 0) {
1636 pps->ppsinfo.current_mode = pps->ppsparam.mode;
1637 fapi->pps_info_buf = pps->ppsinfo;
1643 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1646 struct pps_fetch_args *fapi;
1648 struct pps_fetch_ffc_args *fapi_ffc;
1651 struct pps_kcbind_args *kapi;
1654 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
1656 case PPS_IOC_CREATE:
1658 case PPS_IOC_DESTROY:
1660 case PPS_IOC_SETPARAMS:
1661 app = (pps_params_t *)data;
1662 if (app->mode & ~pps->ppscap)
1665 /* Ensure only a single clock is selected for ffc timestamp. */
1666 if ((app->mode & PPS_TSCLK_MASK) == PPS_TSCLK_MASK)
1669 pps->ppsparam = *app;
1671 case PPS_IOC_GETPARAMS:
1672 app = (pps_params_t *)data;
1673 *app = pps->ppsparam;
1674 app->api_version = PPS_API_VERS_1;
1676 case PPS_IOC_GETCAP:
1677 *(int*)data = pps->ppscap;
1680 fapi = (struct pps_fetch_args *)data;
1681 return (pps_fetch(fapi, pps));
1683 case PPS_IOC_FETCH_FFCOUNTER:
1684 fapi_ffc = (struct pps_fetch_ffc_args *)data;
1685 if (fapi_ffc->tsformat && fapi_ffc->tsformat !=
1688 if (fapi_ffc->timeout.tv_sec || fapi_ffc->timeout.tv_nsec)
1689 return (EOPNOTSUPP);
1690 pps->ppsinfo_ffc.current_mode = pps->ppsparam.mode;
1691 fapi_ffc->pps_info_buf_ffc = pps->ppsinfo_ffc;
1692 /* Overwrite timestamps if feedback clock selected. */
1693 switch (pps->ppsparam.mode & PPS_TSCLK_MASK) {
1694 case PPS_TSCLK_FBCK:
1695 fapi_ffc->pps_info_buf_ffc.assert_timestamp =
1696 pps->ppsinfo.assert_timestamp;
1697 fapi_ffc->pps_info_buf_ffc.clear_timestamp =
1698 pps->ppsinfo.clear_timestamp;
1700 case PPS_TSCLK_FFWD:
1706 #endif /* FFCLOCK */
1707 case PPS_IOC_KCBIND:
1709 kapi = (struct pps_kcbind_args *)data;
1710 /* XXX Only root should be able to do this */
1711 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1713 if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1715 if (kapi->edge & ~pps->ppscap)
1717 pps->kcmode = (kapi->edge & KCMODE_EDGEMASK) |
1718 (pps->kcmode & KCMODE_ABIFLAG);
1721 return (EOPNOTSUPP);
1729 pps_init(struct pps_state *pps)
1731 pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT;
1732 if (pps->ppscap & PPS_CAPTUREASSERT)
1733 pps->ppscap |= PPS_OFFSETASSERT;
1734 if (pps->ppscap & PPS_CAPTURECLEAR)
1735 pps->ppscap |= PPS_OFFSETCLEAR;
1737 pps->ppscap |= PPS_TSCLK_MASK;
1739 pps->kcmode &= ~KCMODE_ABIFLAG;
1743 pps_init_abi(struct pps_state *pps)
1747 if (pps->driver_abi > 0) {
1748 pps->kcmode |= KCMODE_ABIFLAG;
1749 pps->kernel_abi = PPS_ABI_VERSION;
1754 pps_capture(struct pps_state *pps)
1756 struct timehands *th;
1758 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
1760 pps->capgen = atomic_load_acq_int(&th->th_generation);
1763 pps->capffth = fftimehands;
1765 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
1766 atomic_thread_fence_acq();
1767 if (pps->capgen != th->th_generation)
1772 pps_event(struct pps_state *pps, int event)
1775 struct timespec ts, *tsp, *osp;
1776 u_int tcount, *pcount;
1780 struct timespec *tsp_ffc;
1781 pps_seq_t *pseq_ffc;
1788 KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
1789 /* Nothing to do if not currently set to capture this event type. */
1790 if ((event & pps->ppsparam.mode) == 0)
1792 /* If the timecounter was wound up underneath us, bail out. */
1793 if (pps->capgen == 0 || pps->capgen !=
1794 atomic_load_acq_int(&pps->capth->th_generation))
1797 /* Things would be easier with arrays. */
1798 if (event == PPS_CAPTUREASSERT) {
1799 tsp = &pps->ppsinfo.assert_timestamp;
1800 osp = &pps->ppsparam.assert_offset;
1801 foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1803 fhard = pps->kcmode & PPS_CAPTUREASSERT;
1805 pcount = &pps->ppscount[0];
1806 pseq = &pps->ppsinfo.assert_sequence;
1808 ffcount = &pps->ppsinfo_ffc.assert_ffcount;
1809 tsp_ffc = &pps->ppsinfo_ffc.assert_timestamp;
1810 pseq_ffc = &pps->ppsinfo_ffc.assert_sequence;
1813 tsp = &pps->ppsinfo.clear_timestamp;
1814 osp = &pps->ppsparam.clear_offset;
1815 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1817 fhard = pps->kcmode & PPS_CAPTURECLEAR;
1819 pcount = &pps->ppscount[1];
1820 pseq = &pps->ppsinfo.clear_sequence;
1822 ffcount = &pps->ppsinfo_ffc.clear_ffcount;
1823 tsp_ffc = &pps->ppsinfo_ffc.clear_timestamp;
1824 pseq_ffc = &pps->ppsinfo_ffc.clear_sequence;
1829 * If the timecounter changed, we cannot compare the count values, so
1830 * we have to drop the rest of the PPS-stuff until the next event.
1832 if (pps->ppstc != pps->capth->th_counter) {
1833 pps->ppstc = pps->capth->th_counter;
1834 *pcount = pps->capcount;
1835 pps->ppscount[2] = pps->capcount;
1839 /* Convert the count to a timespec. */
1840 tcount = pps->capcount - pps->capth->th_offset_count;
1841 tcount &= pps->capth->th_counter->tc_counter_mask;
1842 bt = pps->capth->th_bintime;
1843 bintime_addx(&bt, pps->capth->th_scale * tcount);
1844 bintime2timespec(&bt, &ts);
1846 /* If the timecounter was wound up underneath us, bail out. */
1847 atomic_thread_fence_acq();
1848 if (pps->capgen != pps->capth->th_generation)
1851 *pcount = pps->capcount;
1856 timespecadd(tsp, osp, tsp);
1857 if (tsp->tv_nsec < 0) {
1858 tsp->tv_nsec += 1000000000;
1864 *ffcount = pps->capffth->tick_ffcount + tcount;
1865 bt = pps->capffth->tick_time;
1866 ffclock_convert_delta(tcount, pps->capffth->cest.period, &bt);
1867 bintime_add(&bt, &pps->capffth->tick_time);
1868 bintime2timespec(&bt, &ts);
1878 * Feed the NTP PLL/FLL.
1879 * The FLL wants to know how many (hardware) nanoseconds
1880 * elapsed since the previous event.
1882 tcount = pps->capcount - pps->ppscount[2];
1883 pps->ppscount[2] = pps->capcount;
1884 tcount &= pps->capth->th_counter->tc_counter_mask;
1885 scale = (uint64_t)1 << 63;
1886 scale /= pps->capth->th_counter->tc_frequency;
1890 bintime_addx(&bt, scale * tcount);
1891 bintime2timespec(&bt, &ts);
1892 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
1896 /* Wakeup anyone sleeping in pps_fetch(). */
1901 * Timecounters need to be updated every so often to prevent the hardware
1902 * counter from overflowing. Updating also recalculates the cached values
1903 * used by the get*() family of functions, so their precision depends on
1904 * the update frequency.
1908 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0,
1909 "Approximate number of hardclock ticks in a millisecond");
1912 tc_ticktock(int cnt)
1916 if (mtx_trylock_spin(&tc_setclock_mtx)) {
1918 if (count >= tc_tick) {
1922 mtx_unlock_spin(&tc_setclock_mtx);
1926 static void __inline
1927 tc_adjprecision(void)
1931 if (tc_timepercentage > 0) {
1932 t = (99 + tc_timepercentage) / tc_timepercentage;
1933 tc_precexp = fls(t + (t >> 1)) - 1;
1934 FREQ2BT(hz / tc_tick, &bt_timethreshold);
1935 FREQ2BT(hz, &bt_tickthreshold);
1936 bintime_shift(&bt_timethreshold, tc_precexp);
1937 bintime_shift(&bt_tickthreshold, tc_precexp);
1940 bt_timethreshold.sec = INT_MAX;
1941 bt_timethreshold.frac = ~(uint64_t)0;
1942 bt_tickthreshold = bt_timethreshold;
1944 sbt_timethreshold = bttosbt(bt_timethreshold);
1945 sbt_tickthreshold = bttosbt(bt_tickthreshold);
1949 sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS)
1953 val = tc_timepercentage;
1954 error = sysctl_handle_int(oidp, &val, 0, req);
1955 if (error != 0 || req->newptr == NULL)
1957 tc_timepercentage = val;
1965 /* Set up the requested number of timehands. */
1967 inittimehands(void *dummy)
1969 struct timehands *thp;
1972 TUNABLE_INT_FETCH("kern.timecounter.timehands_count",
1974 if (timehands_count < 1)
1975 timehands_count = 1;
1976 if (timehands_count > nitems(ths))
1977 timehands_count = nitems(ths);
1978 for (i = 1, thp = &ths[0]; i < timehands_count; thp = &ths[i++])
1979 thp->th_next = &ths[i];
1980 thp->th_next = &ths[0];
1982 TUNABLE_STR_FETCH("kern.timecounter.hardware", tc_from_tunable,
1983 sizeof(tc_from_tunable));
1985 mtx_init(&tc_lock, "tc", NULL, MTX_DEF);
1987 SYSINIT(timehands, SI_SUB_TUNABLES, SI_ORDER_ANY, inittimehands, NULL);
1990 inittimecounter(void *dummy)
1996 * Set the initial timeout to
1997 * max(1, <approx. number of hardclock ticks in a millisecond>).
1998 * People should probably not use the sysctl to set the timeout
1999 * to smaller than its initial value, since that value is the
2000 * smallest reasonable one. If they want better timestamps they
2001 * should use the non-"get"* functions.
2004 tc_tick = (hz + 500) / 1000;
2008 FREQ2BT(hz, &tick_bt);
2009 tick_sbt = bttosbt(tick_bt);
2010 tick_rate = hz / tc_tick;
2011 FREQ2BT(tick_rate, &tc_tick_bt);
2012 tc_tick_sbt = bttosbt(tc_tick_bt);
2013 p = (tc_tick * 1000000) / hz;
2014 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
2020 /* warm up new timecounter (again) and get rolling. */
2021 (void)timecounter->tc_get_timecount(timecounter);
2022 mtx_lock_spin(&tc_setclock_mtx);
2024 mtx_unlock_spin(&tc_setclock_mtx);
2027 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL);
2029 /* Cpu tick handling -------------------------------------------------*/
2031 static int cpu_tick_variable;
2032 static uint64_t cpu_tick_frequency;
2034 DPCPU_DEFINE_STATIC(uint64_t, tc_cpu_ticks_base);
2035 DPCPU_DEFINE_STATIC(unsigned, tc_cpu_ticks_last);
2040 struct timecounter *tc;
2041 uint64_t res, *base;
2045 base = DPCPU_PTR(tc_cpu_ticks_base);
2046 last = DPCPU_PTR(tc_cpu_ticks_last);
2047 tc = timehands->th_counter;
2048 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
2050 *base += (uint64_t)tc->tc_counter_mask + 1;
2058 cpu_tick_calibration(void)
2060 static time_t last_calib;
2062 if (time_uptime != last_calib && !(time_uptime & 0xf)) {
2063 cpu_tick_calibrate(0);
2064 last_calib = time_uptime;
2069 * This function gets called every 16 seconds on only one designated
2070 * CPU in the system from hardclock() via cpu_tick_calibration()().
2072 * Whenever the real time clock is stepped we get called with reset=1
2073 * to make sure we handle suspend/resume and similar events correctly.
2077 cpu_tick_calibrate(int reset)
2079 static uint64_t c_last;
2080 uint64_t c_this, c_delta;
2081 static struct bintime t_last;
2082 struct bintime t_this, t_delta;
2086 /* The clock was stepped, abort & reset */
2091 /* we don't calibrate fixed rate cputicks */
2092 if (!cpu_tick_variable)
2095 getbinuptime(&t_this);
2096 c_this = cpu_ticks();
2097 if (t_last.sec != 0) {
2098 c_delta = c_this - c_last;
2100 bintime_sub(&t_delta, &t_last);
2103 * 2^(64-20) / 16[s] =
2105 * 17.592.186.044.416 / 16 =
2106 * 1.099.511.627.776 [Hz]
2108 divi = t_delta.sec << 20;
2109 divi |= t_delta.frac >> (64 - 20);
2112 if (c_delta > cpu_tick_frequency) {
2113 if (0 && bootverbose)
2114 printf("cpu_tick increased to %ju Hz\n",
2116 cpu_tick_frequency = c_delta;
2124 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
2128 cpu_ticks = tc_cpu_ticks;
2130 cpu_tick_frequency = freq;
2131 cpu_tick_variable = var;
2140 if (cpu_ticks == tc_cpu_ticks)
2141 return (tc_getfrequency());
2142 return (cpu_tick_frequency);
2146 * We need to be slightly careful converting cputicks to microseconds.
2147 * There is plenty of margin in 64 bits of microseconds (half a million
2148 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
2149 * before divide conversion (to retain precision) we find that the
2150 * margin shrinks to 1.5 hours (one millionth of 146y).
2151 * With a three prong approach we never lose significant bits, no
2152 * matter what the cputick rate and length of timeinterval is.
2156 cputick2usec(uint64_t tick)
2159 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */
2160 return (tick / (cpu_tickrate() / 1000000LL));
2161 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */
2162 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
2164 return ((tick * 1000000LL) / cpu_tickrate());
2167 cpu_tick_f *cpu_ticks = tc_cpu_ticks;
2169 static int vdso_th_enable = 1;
2171 sysctl_fast_gettime(SYSCTL_HANDLER_ARGS)
2173 int old_vdso_th_enable, error;
2175 old_vdso_th_enable = vdso_th_enable;
2176 error = sysctl_handle_int(oidp, &old_vdso_th_enable, 0, req);
2179 vdso_th_enable = old_vdso_th_enable;
2182 SYSCTL_PROC(_kern_timecounter, OID_AUTO, fast_gettime,
2183 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
2184 NULL, 0, sysctl_fast_gettime, "I", "Enable fast time of day");
2187 tc_fill_vdso_timehands(struct vdso_timehands *vdso_th)
2189 struct timehands *th;
2193 vdso_th->th_scale = th->th_scale;
2194 vdso_th->th_offset_count = th->th_offset_count;
2195 vdso_th->th_counter_mask = th->th_counter->tc_counter_mask;
2196 vdso_th->th_offset = th->th_offset;
2197 vdso_th->th_boottime = th->th_boottime;
2198 if (th->th_counter->tc_fill_vdso_timehands != NULL) {
2199 enabled = th->th_counter->tc_fill_vdso_timehands(vdso_th,
2203 if (!vdso_th_enable)
2208 #ifdef COMPAT_FREEBSD32
2210 tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32)
2212 struct timehands *th;
2216 *(uint64_t *)&vdso_th32->th_scale[0] = th->th_scale;
2217 vdso_th32->th_offset_count = th->th_offset_count;
2218 vdso_th32->th_counter_mask = th->th_counter->tc_counter_mask;
2219 vdso_th32->th_offset.sec = th->th_offset.sec;
2220 *(uint64_t *)&vdso_th32->th_offset.frac[0] = th->th_offset.frac;
2221 vdso_th32->th_boottime.sec = th->th_boottime.sec;
2222 *(uint64_t *)&vdso_th32->th_boottime.frac[0] = th->th_boottime.frac;
2223 if (th->th_counter->tc_fill_vdso_timehands32 != NULL) {
2224 enabled = th->th_counter->tc_fill_vdso_timehands32(vdso_th32,
2228 if (!vdso_th_enable)
2234 #include "opt_ddb.h"
2236 #include <ddb/ddb.h>
2238 DB_SHOW_COMMAND(timecounter, db_show_timecounter)
2240 struct timehands *th;
2241 struct timecounter *tc;
2245 tc = th->th_counter;
2246 val1 = tc->tc_get_timecount(tc);
2247 __compiler_membar();
2248 val2 = tc->tc_get_timecount(tc);
2250 db_printf("timecounter %p %s\n", tc, tc->tc_name);
2251 db_printf(" mask %#x freq %ju qual %d flags %#x priv %p\n",
2252 tc->tc_counter_mask, (uintmax_t)tc->tc_frequency, tc->tc_quality,
2253 tc->tc_flags, tc->tc_priv);
2254 db_printf(" val %#x %#x\n", val1, val2);
2255 db_printf("timehands adj %#jx scale %#jx ldelta %d off_cnt %d gen %d\n",
2256 (uintmax_t)th->th_adjustment, (uintmax_t)th->th_scale,
2257 th->th_large_delta, th->th_offset_count, th->th_generation);
2258 db_printf(" offset %jd %jd boottime %jd %jd\n",
2259 (intmax_t)th->th_offset.sec, (uintmax_t)th->th_offset.frac,
2260 (intmax_t)th->th_boottime.sec, (uintmax_t)th->th_boottime.frac);