2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
10 #include <sys/cdefs.h>
11 __FBSDID("$FreeBSD$");
15 #include <sys/param.h>
16 #include <sys/kernel.h>
17 #include <sys/sysctl.h>
18 #include <sys/syslog.h>
19 #include <sys/systm.h>
20 #include <sys/timepps.h>
21 #include <sys/timetc.h>
22 #include <sys/timex.h>
25 * A large step happens on boot. This constant detects such steps.
26 * It is relatively small so that ntp_update_second gets called enough
27 * in the typical 'missed a couple of seconds' case, but doesn't loop
28 * forever when the time step is large.
30 #define LARGE_STEP 200
33 * Implement a dummy timecounter which we can use until we get a real one
34 * in the air. This allows the console and other early stuff to use
39 dummy_get_timecount(struct timecounter *tc)
46 static struct timecounter dummy_timecounter = {
47 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
51 /* These fields must be initialized by the driver. */
52 struct timecounter *th_counter;
53 int64_t th_adjustment;
55 u_int th_offset_count;
56 struct bintime th_offset;
57 struct timeval th_microtime;
58 struct timespec th_nanotime;
59 /* Fields not to be copied in tc_windup start with th_generation. */
60 volatile u_int th_generation;
61 struct timehands *th_next;
64 static struct timehands th0;
65 static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0};
66 static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9};
67 static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8};
68 static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7};
69 static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6};
70 static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5};
71 static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4};
72 static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3};
73 static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2};
74 static struct timehands th0 = {
77 (uint64_t)-1 / 1000000,
86 static struct timehands *volatile timehands = &th0;
87 struct timecounter *timecounter = &dummy_timecounter;
88 static struct timecounter *timecounters = &dummy_timecounter;
90 time_t time_second = 1;
91 time_t time_uptime = 1;
93 static struct bintime boottimebin;
94 struct timeval boottime;
95 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
96 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD,
97 NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime");
99 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
100 SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, "");
102 static int timestepwarnings;
103 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
104 ×tepwarnings, 0, "");
106 #define TC_STATS(foo) \
108 SYSCTL_UINT(_kern_timecounter, OID_AUTO, foo, CTLFLAG_RD, &foo, 0, "");\
111 TC_STATS(nbinuptime); TC_STATS(nnanouptime); TC_STATS(nmicrouptime);
112 TC_STATS(nbintime); TC_STATS(nnanotime); TC_STATS(nmicrotime);
113 TC_STATS(ngetbinuptime); TC_STATS(ngetnanouptime); TC_STATS(ngetmicrouptime);
114 TC_STATS(ngetbintime); TC_STATS(ngetnanotime); TC_STATS(ngetmicrotime);
119 static void tc_windup(void);
120 static void cpu_tick_calibrate(int);
123 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
128 if (req->flags & SCTL_MASK32) {
129 tv[0] = boottime.tv_sec;
130 tv[1] = boottime.tv_usec;
131 return SYSCTL_OUT(req, tv, sizeof(tv));
134 return SYSCTL_OUT(req, &boottime, sizeof(boottime));
138 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
141 struct timecounter *tc = arg1;
143 ncount = tc->tc_get_timecount(tc);
144 return sysctl_handle_int(oidp, &ncount, sizeof(ncount), req);
148 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
151 struct timecounter *tc = arg1;
153 freq = tc->tc_frequency;
154 return sysctl_handle_int(oidp, &freq, sizeof(freq), req);
158 * Return the difference between the timehands' counter value now and what
159 * was when we copied it to the timehands' offset_count.
161 static __inline u_int
162 tc_delta(struct timehands *th)
164 struct timecounter *tc;
167 return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
168 tc->tc_counter_mask);
172 * Functions for reading the time. We have to loop until we are sure that
173 * the timehands that we operated on was not updated under our feet. See
174 * the comment in <sys/time.h> for a description of these 12 functions.
178 binuptime(struct bintime *bt)
180 struct timehands *th;
186 gen = th->th_generation;
188 bintime_addx(bt, th->th_scale * tc_delta(th));
189 } while (gen == 0 || gen != th->th_generation);
193 nanouptime(struct timespec *tsp)
199 bintime2timespec(&bt, tsp);
203 microuptime(struct timeval *tvp)
209 bintime2timeval(&bt, tvp);
213 bintime(struct bintime *bt)
218 bintime_add(bt, &boottimebin);
222 nanotime(struct timespec *tsp)
228 bintime2timespec(&bt, tsp);
232 microtime(struct timeval *tvp)
238 bintime2timeval(&bt, tvp);
242 getbinuptime(struct bintime *bt)
244 struct timehands *th;
250 gen = th->th_generation;
252 } while (gen == 0 || gen != th->th_generation);
256 getnanouptime(struct timespec *tsp)
258 struct timehands *th;
264 gen = th->th_generation;
265 bintime2timespec(&th->th_offset, tsp);
266 } while (gen == 0 || gen != th->th_generation);
270 getmicrouptime(struct timeval *tvp)
272 struct timehands *th;
278 gen = th->th_generation;
279 bintime2timeval(&th->th_offset, tvp);
280 } while (gen == 0 || gen != th->th_generation);
284 getbintime(struct bintime *bt)
286 struct timehands *th;
292 gen = th->th_generation;
294 } while (gen == 0 || gen != th->th_generation);
295 bintime_add(bt, &boottimebin);
299 getnanotime(struct timespec *tsp)
301 struct timehands *th;
307 gen = th->th_generation;
308 *tsp = th->th_nanotime;
309 } while (gen == 0 || gen != th->th_generation);
313 getmicrotime(struct timeval *tvp)
315 struct timehands *th;
321 gen = th->th_generation;
322 *tvp = th->th_microtime;
323 } while (gen == 0 || gen != th->th_generation);
327 * Initialize a new timecounter and possibly use it.
330 tc_init(struct timecounter *tc)
333 struct sysctl_oid *tc_root;
335 u = tc->tc_frequency / tc->tc_counter_mask;
336 /* XXX: We need some margin here, 10% is a guess */
339 if (u > hz && tc->tc_quality >= 0) {
340 tc->tc_quality = -2000;
342 printf("Timecounter \"%s\" frequency %ju Hz",
343 tc->tc_name, (uintmax_t)tc->tc_frequency);
344 printf(" -- Insufficient hz, needs at least %u\n", u);
346 } else if (tc->tc_quality >= 0 || bootverbose) {
347 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
348 tc->tc_name, (uintmax_t)tc->tc_frequency,
352 tc->tc_next = timecounters;
355 * Set up sysctl tree for this counter.
357 tc_root = SYSCTL_ADD_NODE(NULL,
358 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
359 CTLFLAG_RW, 0, "timecounter description");
360 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
361 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
362 "mask for implemented bits");
363 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
364 "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc),
365 sysctl_kern_timecounter_get, "IU", "current timecounter value");
366 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
367 "frequency", CTLTYPE_QUAD | CTLFLAG_RD, tc, sizeof(*tc),
368 sysctl_kern_timecounter_freq, "IU", "timecounter frequency");
369 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
370 "quality", CTLFLAG_RD, &(tc->tc_quality), 0,
371 "goodness of time counter");
373 * Never automatically use a timecounter with negative quality.
374 * Even though we run on the dummy counter, switching here may be
375 * worse since this timecounter may not be monotonous.
377 if (tc->tc_quality < 0)
379 if (tc->tc_quality < timecounter->tc_quality)
381 if (tc->tc_quality == timecounter->tc_quality &&
382 tc->tc_frequency < timecounter->tc_frequency)
384 (void)tc->tc_get_timecount(tc);
385 (void)tc->tc_get_timecount(tc);
389 /* Report the frequency of the current timecounter. */
391 tc_getfrequency(void)
394 return (timehands->th_counter->tc_frequency);
398 * Step our concept of UTC. This is done by modifying our estimate of
403 tc_setclock(struct timespec *ts)
405 struct timespec tbef, taft;
406 struct bintime bt, bt2;
408 cpu_tick_calibrate(1);
411 timespec2bintime(ts, &bt);
413 bintime_sub(&bt, &bt2);
414 bintime_add(&bt2, &boottimebin);
416 bintime2timeval(&bt, &boottime);
418 /* XXX fiddle all the little crinkly bits around the fiords... */
421 if (timestepwarnings) {
423 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
424 (intmax_t)tbef.tv_sec, tbef.tv_nsec,
425 (intmax_t)taft.tv_sec, taft.tv_nsec,
426 (intmax_t)ts->tv_sec, ts->tv_nsec);
428 cpu_tick_calibrate(1);
432 * Initialize the next struct timehands in the ring and make
433 * it the active timehands. Along the way we might switch to a different
434 * timecounter and/or do seconds processing in NTP. Slightly magic.
440 struct timehands *th, *tho;
442 u_int delta, ncount, ogen;
447 * Make the next timehands a copy of the current one, but do not
448 * overwrite the generation or next pointer. While we update
449 * the contents, the generation must be zero.
453 ogen = th->th_generation;
454 th->th_generation = 0;
455 bcopy(tho, th, offsetof(struct timehands, th_generation));
458 * Capture a timecounter delta on the current timecounter and if
459 * changing timecounters, a counter value from the new timecounter.
460 * Update the offset fields accordingly.
462 delta = tc_delta(th);
463 if (th->th_counter != timecounter)
464 ncount = timecounter->tc_get_timecount(timecounter);
467 th->th_offset_count += delta;
468 th->th_offset_count &= th->th_counter->tc_counter_mask;
469 bintime_addx(&th->th_offset, th->th_scale * delta);
472 * Hardware latching timecounters may not generate interrupts on
473 * PPS events, so instead we poll them. There is a finite risk that
474 * the hardware might capture a count which is later than the one we
475 * got above, and therefore possibly in the next NTP second which might
476 * have a different rate than the current NTP second. It doesn't
477 * matter in practice.
479 if (tho->th_counter->tc_poll_pps)
480 tho->th_counter->tc_poll_pps(tho->th_counter);
483 * Deal with NTP second processing. The for loop normally
484 * iterates at most once, but in extreme situations it might
485 * keep NTP sane if timeouts are not run for several seconds.
486 * At boot, the time step can be large when the TOD hardware
487 * has been read, so on really large steps, we call
488 * ntp_update_second only twice. We need to call it twice in
489 * case we missed a leap second.
492 bintime_add(&bt, &boottimebin);
493 i = bt.sec - tho->th_microtime.tv_sec;
498 ntp_update_second(&th->th_adjustment, &bt.sec);
500 boottimebin.sec += bt.sec - t;
502 /* Update the UTC timestamps used by the get*() functions. */
503 /* XXX shouldn't do this here. Should force non-`get' versions. */
504 bintime2timeval(&bt, &th->th_microtime);
505 bintime2timespec(&bt, &th->th_nanotime);
507 /* Now is a good time to change timecounters. */
508 if (th->th_counter != timecounter) {
509 th->th_counter = timecounter;
510 th->th_offset_count = ncount;
514 * Recalculate the scaling factor. We want the number of 1/2^64
515 * fractions of a second per period of the hardware counter, taking
516 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
517 * processing provides us with.
519 * The th_adjustment is nanoseconds per second with 32 bit binary
520 * fraction and we want 64 bit binary fraction of second:
522 * x = a * 2^32 / 10^9 = a * 4.294967296
524 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
525 * we can only multiply by about 850 without overflowing, that
526 * leaves no suitably precise fractions for multiply before divide.
528 * Divide before multiply with a fraction of 2199/512 results in a
529 * systematic undercompensation of 10PPM of th_adjustment. On a
530 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
532 * We happily sacrifice the lowest of the 64 bits of our result
533 * to the goddess of code clarity.
536 scale = (u_int64_t)1 << 63;
537 scale += (th->th_adjustment / 1024) * 2199;
538 scale /= th->th_counter->tc_frequency;
539 th->th_scale = scale * 2;
542 * Now that the struct timehands is again consistent, set the new
543 * generation number, making sure to not make it zero.
547 th->th_generation = ogen;
549 /* Go live with the new struct timehands. */
550 time_second = th->th_microtime.tv_sec;
551 time_uptime = th->th_offset.sec;
555 /* Report or change the active timecounter hardware. */
557 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
560 struct timecounter *newtc, *tc;
564 strlcpy(newname, tc->tc_name, sizeof(newname));
566 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
567 if (error != 0 || req->newptr == NULL ||
568 strcmp(newname, tc->tc_name) == 0)
570 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
571 if (strcmp(newname, newtc->tc_name) != 0)
574 /* Warm up new timecounter. */
575 (void)newtc->tc_get_timecount(newtc);
576 (void)newtc->tc_get_timecount(newtc);
584 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
585 0, 0, sysctl_kern_timecounter_hardware, "A", "");
588 /* Report or change the active timecounter hardware. */
590 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
593 struct timecounter *tc;
598 for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) {
599 sprintf(buf, "%s%s(%d)",
600 spc, tc->tc_name, tc->tc_quality);
601 error = SYSCTL_OUT(req, buf, strlen(buf));
607 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
608 0, 0, sysctl_kern_timecounter_choice, "A", "");
611 * RFC 2783 PPS-API implementation.
615 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
618 struct pps_fetch_args *fapi;
620 struct pps_kcbind_args *kapi;
623 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
627 case PPS_IOC_DESTROY:
629 case PPS_IOC_SETPARAMS:
630 app = (pps_params_t *)data;
631 if (app->mode & ~pps->ppscap)
633 pps->ppsparam = *app;
635 case PPS_IOC_GETPARAMS:
636 app = (pps_params_t *)data;
637 *app = pps->ppsparam;
638 app->api_version = PPS_API_VERS_1;
641 *(int*)data = pps->ppscap;
644 fapi = (struct pps_fetch_args *)data;
645 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
647 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
649 pps->ppsinfo.current_mode = pps->ppsparam.mode;
650 fapi->pps_info_buf = pps->ppsinfo;
654 kapi = (struct pps_kcbind_args *)data;
655 /* XXX Only root should be able to do this */
656 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
658 if (kapi->kernel_consumer != PPS_KC_HARDPPS)
660 if (kapi->edge & ~pps->ppscap)
662 pps->kcmode = kapi->edge;
673 pps_init(struct pps_state *pps)
675 pps->ppscap |= PPS_TSFMT_TSPEC;
676 if (pps->ppscap & PPS_CAPTUREASSERT)
677 pps->ppscap |= PPS_OFFSETASSERT;
678 if (pps->ppscap & PPS_CAPTURECLEAR)
679 pps->ppscap |= PPS_OFFSETCLEAR;
683 pps_capture(struct pps_state *pps)
685 struct timehands *th;
687 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
689 pps->capgen = th->th_generation;
691 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
692 if (pps->capgen != th->th_generation)
697 pps_event(struct pps_state *pps, int event)
700 struct timespec ts, *tsp, *osp;
701 u_int tcount, *pcount;
705 KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
706 /* If the timecounter was wound up underneath us, bail out. */
707 if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation)
710 /* Things would be easier with arrays. */
711 if (event == PPS_CAPTUREASSERT) {
712 tsp = &pps->ppsinfo.assert_timestamp;
713 osp = &pps->ppsparam.assert_offset;
714 foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
715 fhard = pps->kcmode & PPS_CAPTUREASSERT;
716 pcount = &pps->ppscount[0];
717 pseq = &pps->ppsinfo.assert_sequence;
719 tsp = &pps->ppsinfo.clear_timestamp;
720 osp = &pps->ppsparam.clear_offset;
721 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
722 fhard = pps->kcmode & PPS_CAPTURECLEAR;
723 pcount = &pps->ppscount[1];
724 pseq = &pps->ppsinfo.clear_sequence;
728 * If the timecounter changed, we cannot compare the count values, so
729 * we have to drop the rest of the PPS-stuff until the next event.
731 if (pps->ppstc != pps->capth->th_counter) {
732 pps->ppstc = pps->capth->th_counter;
733 *pcount = pps->capcount;
734 pps->ppscount[2] = pps->capcount;
738 /* Convert the count to a timespec. */
739 tcount = pps->capcount - pps->capth->th_offset_count;
740 tcount &= pps->capth->th_counter->tc_counter_mask;
741 bt = pps->capth->th_offset;
742 bintime_addx(&bt, pps->capth->th_scale * tcount);
743 bintime_add(&bt, &boottimebin);
744 bintime2timespec(&bt, &ts);
746 /* If the timecounter was wound up underneath us, bail out. */
747 if (pps->capgen != pps->capth->th_generation)
750 *pcount = pps->capcount;
755 timespecadd(tsp, osp);
756 if (tsp->tv_nsec < 0) {
757 tsp->tv_nsec += 1000000000;
766 * Feed the NTP PLL/FLL.
767 * The FLL wants to know how many (hardware) nanoseconds
768 * elapsed since the previous event.
770 tcount = pps->capcount - pps->ppscount[2];
771 pps->ppscount[2] = pps->capcount;
772 tcount &= pps->capth->th_counter->tc_counter_mask;
773 scale = (u_int64_t)1 << 63;
774 scale /= pps->capth->th_counter->tc_frequency;
778 bintime_addx(&bt, scale * tcount);
779 bintime2timespec(&bt, &ts);
780 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
786 * Timecounters need to be updated every so often to prevent the hardware
787 * counter from overflowing. Updating also recalculates the cached values
788 * used by the get*() family of functions, so their precision depends on
789 * the update frequency.
793 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, "");
799 static time_t last_calib;
801 if (++count < tc_tick)
805 if (time_uptime != last_calib && !(time_uptime & 0xf)) {
806 cpu_tick_calibrate(0);
807 last_calib = time_uptime;
812 inittimecounter(void *dummy)
817 * Set the initial timeout to
818 * max(1, <approx. number of hardclock ticks in a millisecond>).
819 * People should probably not use the sysctl to set the timeout
820 * to smaller than its inital value, since that value is the
821 * smallest reasonable one. If they want better timestamps they
822 * should use the non-"get"* functions.
825 tc_tick = (hz + 500) / 1000;
828 p = (tc_tick * 1000000) / hz;
829 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
831 /* warm up new timecounter (again) and get rolling. */
832 (void)timecounter->tc_get_timecount(timecounter);
833 (void)timecounter->tc_get_timecount(timecounter);
836 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL)
838 /* Cpu tick handling -------------------------------------------------*/
840 static int cpu_tick_variable;
841 static uint64_t cpu_tick_frequency;
846 static uint64_t base;
847 static unsigned last;
849 struct timecounter *tc;
851 tc = timehands->th_counter;
852 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
854 base += (uint64_t)tc->tc_counter_mask + 1;
860 * This function gets called ever 16 seconds on only one designated
861 * CPU in the system from hardclock() via tc_ticktock().
863 * Whenever the real time clock is stepped we get called with reset=1
864 * to make sure we handle suspend/resume and similar events correctly.
868 cpu_tick_calibrate(int reset)
870 static uint64_t c_last;
871 uint64_t c_this, c_delta;
872 static struct bintime t_last;
873 struct bintime t_this, t_delta;
877 /* The clock was stepped, abort & reset */
882 /* we don't calibrate fixed rate cputicks */
883 if (!cpu_tick_variable)
886 getbinuptime(&t_this);
887 c_this = cpu_ticks();
888 if (t_last.sec != 0) {
889 c_delta = c_this - c_last;
891 bintime_sub(&t_delta, &t_last);
893 * Validate that 16 +/- 1/256 seconds passed.
894 * After division by 16 this gives us a precision of
895 * roughly 250PPM which is sufficient
897 if (t_delta.sec > 16 || (
898 t_delta.sec == 16 && t_delta.frac >= (0x01LL << 56))) {
901 printf("%ju.%016jx too long\n",
902 (uintmax_t)t_delta.sec,
903 (uintmax_t)t_delta.frac);
904 } else if (t_delta.sec < 15 ||
905 (t_delta.sec == 15 && t_delta.frac <= (0xffLL << 56))) {
908 printf("%ju.%016jx too short\n",
909 (uintmax_t)t_delta.sec,
910 (uintmax_t)t_delta.frac);
915 * 2^(64-20) / 16[s] =
917 * 17.592.186.044.416 / 16 =
918 * 1.099.511.627.776 [Hz]
920 divi = t_delta.sec << 20;
921 divi |= t_delta.frac >> (64 - 20);
924 if (c_delta > cpu_tick_frequency) {
925 if (0 && bootverbose)
926 printf("cpu_tick increased to %ju Hz\n",
928 cpu_tick_frequency = c_delta;
937 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
941 cpu_ticks = tc_cpu_ticks;
943 cpu_tick_frequency = freq;
944 cpu_tick_variable = var;
953 if (cpu_ticks == tc_cpu_ticks)
954 return (tc_getfrequency());
955 return (cpu_tick_frequency);
959 * We need to be slightly careful converting cputicks to microseconds.
960 * There is plenty of margin in 64 bits of microseconds (half a million
961 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
962 * before divide conversion (to retain precision) we find that the
963 * margin shrinks to 1.5 hours (one millionth of 146y).
964 * With a three prong approach we never lose significant bits, no
965 * matter what the cputick rate and length of timeinterval is.
969 cputick2usec(uint64_t tick)
972 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */
973 return (tick / (cpu_tickrate() / 1000000LL));
974 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */
975 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
977 return ((tick * 1000000LL) / cpu_tickrate());
980 cpu_tick_f *cpu_ticks = tc_cpu_ticks;