2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
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13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
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17 * 4. Neither the name of the University nor the names of its contributors
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33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $
37 #include <sys/param.h>
38 #include <sys/systm.h>
40 #include <sys/sysproto.h>
41 #include <sys/resourcevar.h>
42 #include <sys/signalvar.h>
43 #include <sys/kernel.h>
44 #include <sys/sysent.h>
45 #include <sys/sysunion.h>
49 #include <sys/vnode.h>
50 #include <sys/sysctl.h>
51 #include <sys/kern_syscall.h>
53 #include <vm/vm_extern.h>
55 #include <sys/msgport2.h>
56 #include <sys/thread2.h>
57 #include <sys/mplock2.h>
62 * Time of day and interval timer support.
64 * These routines provide the kernel entry points to get and set
65 * the time-of-day and per-process interval timers. Subroutines
66 * here provide support for adding and subtracting timeval structures
67 * and decrementing interval timers, optionally reloading the interval
68 * timers when they expire.
71 static int settime(struct timeval *);
72 static void timevalfix(struct timeval *);
75 * Nanosleep tries very hard to sleep for a precisely requested time
76 * interval, down to 1uS. The administrator can impose a minimum delay
77 * and a delay below which we hard-loop instead of initiate a timer
78 * interrupt and sleep.
80 * For machines under high loads it might be beneficial to increase min_us
81 * to e.g. 1000uS (1ms) so spining processes sleep meaningfully.
83 static int nanosleep_min_us = 10;
84 static int nanosleep_hard_us = 100;
85 static int gettimeofday_quick = 0;
86 SYSCTL_INT(_kern, OID_AUTO, nanosleep_min_us, CTLFLAG_RW,
87 &nanosleep_min_us, 0, "")
88 SYSCTL_INT(_kern, OID_AUTO, nanosleep_hard_us, CTLFLAG_RW,
89 &nanosleep_hard_us, 0, "")
90 SYSCTL_INT(_kern, OID_AUTO, gettimeofday_quick, CTLFLAG_RW,
91 &gettimeofday_quick, 0, "")
94 settime(struct timeval *tv)
96 struct timeval delta, tv1, tv2;
97 static struct timeval maxtime, laststep;
101 if ((origcpu = mycpu->gd_cpuid) != 0)
102 lwkt_setcpu_self(globaldata_find(0));
107 timevalsub(&delta, &tv1);
110 * If the system is secure, we do not allow the time to be
111 * set to a value earlier than 1 second less than the highest
112 * time we have yet seen. The worst a miscreant can do in
113 * this circumstance is "freeze" time. He couldn't go
116 * We similarly do not allow the clock to be stepped more
117 * than one second, nor more than once per second. This allows
118 * a miscreant to make the clock march double-time, but no worse.
120 if (securelevel > 1) {
121 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
123 * Update maxtime to latest time we've seen.
125 if (tv1.tv_sec > maxtime.tv_sec)
128 timevalsub(&tv2, &maxtime);
129 if (tv2.tv_sec < -1) {
130 tv->tv_sec = maxtime.tv_sec - 1;
131 kprintf("Time adjustment clamped to -1 second\n");
134 if (tv1.tv_sec == laststep.tv_sec) {
138 if (delta.tv_sec > 1) {
139 tv->tv_sec = tv1.tv_sec + 1;
140 kprintf("Time adjustment clamped to +1 second\n");
146 ts.tv_sec = tv->tv_sec;
147 ts.tv_nsec = tv->tv_usec * 1000;
152 lwkt_setcpu_self(globaldata_find(origcpu));
159 get_curthread_cputime(struct timespec *ats)
161 struct thread *td = curthread;
165 * These are 64-bit fields but the actual values should never reach
166 * the limit. We don't care about overflows.
168 ats->tv_sec = td->td_uticks / 1000000;
169 ats->tv_sec += td->td_sticks / 1000000;
170 ats->tv_sec += td->td_iticks / 1000000;
171 ats->tv_nsec = (td->td_uticks % 1000000) * 1000;
172 ats->tv_nsec += (td->td_sticks % 1000000) * 1000;
173 ats->tv_nsec += (td->td_iticks % 1000000) * 1000;
181 kern_clock_gettime(clockid_t clock_id, struct timespec *ats)
188 case CLOCK_REALTIME_PRECISE:
191 case CLOCK_REALTIME_FAST:
194 case CLOCK_MONOTONIC:
195 case CLOCK_MONOTONIC_PRECISE:
197 case CLOCK_UPTIME_PRECISE:
200 case CLOCK_MONOTONIC_FAST:
201 case CLOCK_UPTIME_FAST:
206 ats->tv_sec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_sec;
207 ats->tv_nsec = p->p_timer[ITIMER_VIRTUAL].it_value.tv_usec *
212 ats->tv_sec = p->p_timer[ITIMER_PROF].it_value.tv_sec;
213 ats->tv_nsec = p->p_timer[ITIMER_PROF].it_value.tv_usec *
217 ats->tv_sec = time_second;
220 case CLOCK_THREAD_CPUTIME_ID:
221 get_curthread_cputime(ats);
234 sys_clock_gettime(struct clock_gettime_args *uap)
239 error = kern_clock_gettime(uap->clock_id, &ats);
241 error = copyout(&ats, uap->tp, sizeof(ats));
247 kern_clock_settime(clockid_t clock_id, struct timespec *ats)
249 struct thread *td = curthread;
253 if ((error = priv_check(td, PRIV_CLOCK_SETTIME)) != 0)
255 if (clock_id != CLOCK_REALTIME)
257 if (ats->tv_nsec < 0 || ats->tv_nsec >= 1000000000)
260 TIMESPEC_TO_TIMEVAL(&atv, ats);
261 error = settime(&atv);
269 sys_clock_settime(struct clock_settime_args *uap)
274 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
278 error = kern_clock_settime(uap->clock_id, &ats);
287 kern_clock_getres(clockid_t clock_id, struct timespec *ts)
293 case CLOCK_REALTIME_FAST:
294 case CLOCK_REALTIME_PRECISE:
295 case CLOCK_MONOTONIC:
296 case CLOCK_MONOTONIC_FAST:
297 case CLOCK_MONOTONIC_PRECISE:
299 case CLOCK_UPTIME_FAST:
300 case CLOCK_UPTIME_PRECISE:
301 case CLOCK_THREAD_CPUTIME_ID:
303 * Round up the result of the division cheaply
304 * by adding 1. Rounding up is especially important
305 * if rounding down would give 0. Perfect rounding
309 ts->tv_nsec = 1000000000 / sys_cputimer->freq + 1;
314 /* Accurately round up here because we can do so cheaply. */
316 ts->tv_nsec = (1000000000 + hz - 1) / hz;
336 sys_clock_getres(struct clock_getres_args *uap)
341 error = kern_clock_getres(uap->clock_id, &ts);
343 error = copyout(&ts, uap->tp, sizeof(ts));
351 * This is a general helper function for nanosleep() (aka sleep() aka
354 * If there is less then one tick's worth of time left and
355 * we haven't done a yield, or the remaining microseconds is
356 * ridiculously low, do a yield. This avoids having
357 * to deal with systimer overheads when the system is under
358 * heavy loads. If we have done a yield already then use
359 * a systimer and an uninterruptable thread wait.
361 * If there is more then a tick's worth of time left,
362 * calculate the baseline ticks and use an interruptable
363 * tsleep, then handle the fine-grained delay on the next
364 * loop. This usually results in two sleeps occuring, a long one
370 ns1_systimer(systimer_t info, int in_ipi __unused,
371 struct intrframe *frame __unused)
373 lwkt_schedule(info->data);
377 nanosleep1(struct timespec *rqt, struct timespec *rmt)
380 struct timespec ts, ts2, ts3;
384 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
386 /* XXX: imho this should return EINVAL at least for tv_sec < 0 */
387 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
390 timespecadd(&ts, rqt); /* ts = target timestamp compare */
391 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */
395 struct systimer info;
397 ticks = tv.tv_usec / ustick; /* approximate */
399 if (tv.tv_sec == 0 && ticks == 0) {
400 thread_t td = curthread;
401 if (tv.tv_usec > 0 && tv.tv_usec < nanosleep_min_us)
402 tv.tv_usec = nanosleep_min_us;
403 if (tv.tv_usec < nanosleep_hard_us) {
407 crit_enter_quick(td);
408 systimer_init_oneshot(&info, ns1_systimer,
410 lwkt_deschedule_self(td);
413 systimer_del(&info); /* make sure it's gone */
415 error = iscaught(td->td_lwp);
416 } else if (tv.tv_sec == 0) {
417 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
419 ticks = tvtohz_low(&tv); /* also handles overflow */
420 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
423 if (error && error != EWOULDBLOCK) {
424 if (error == ERESTART)
427 timespecsub(&ts, &ts2);
434 if (timespeccmp(&ts2, &ts, >=))
437 timespecsub(&ts3, &ts2);
438 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
446 sys_nanosleep(struct nanosleep_args *uap)
452 error = copyin(uap->rqtp, &rqt, sizeof(rqt));
456 error = nanosleep1(&rqt, &rmt);
459 * copyout the residual if nanosleep was interrupted.
461 if (error && uap->rmtp) {
464 error2 = copyout(&rmt, uap->rmtp, sizeof(rmt));
472 * The gettimeofday() system call is supposed to return a fine-grained
473 * realtime stamp. However, acquiring a fine-grained stamp can create a
474 * bottleneck when multiple cpu cores are trying to accessing e.g. the
475 * HPET hardware timer all at the same time, so we have a sysctl that
476 * allows its behavior to be changed to a more coarse-grained timestamp
477 * which does not have to access a hardware timer.
480 sys_gettimeofday(struct gettimeofday_args *uap)
486 if (gettimeofday_quick)
490 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
495 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
504 sys_settimeofday(struct settimeofday_args *uap)
506 struct thread *td = curthread;
511 if ((error = priv_check(td, PRIV_SETTIMEOFDAY)))
514 * Verify all parameters before changing time.
516 * NOTE: We do not allow the time to be set to 0.0, which also by
517 * happy coincidence works around a pkgsrc bulk build bug.
520 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
523 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
525 if (atv.tv_sec == 0 && atv.tv_usec == 0)
529 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
533 if (uap->tv && (error = settime(&atv))) {
544 kern_adjtime_common(void)
546 if ((ntp_delta >= 0 && ntp_delta < ntp_default_tick_delta) ||
547 (ntp_delta < 0 && ntp_delta > -ntp_default_tick_delta))
548 ntp_tick_delta = ntp_delta;
549 else if (ntp_delta > ntp_big_delta)
550 ntp_tick_delta = 10 * ntp_default_tick_delta;
551 else if (ntp_delta < -ntp_big_delta)
552 ntp_tick_delta = -10 * ntp_default_tick_delta;
553 else if (ntp_delta > 0)
554 ntp_tick_delta = ntp_default_tick_delta;
556 ntp_tick_delta = -ntp_default_tick_delta;
560 kern_adjtime(int64_t delta, int64_t *odelta)
564 if ((origcpu = mycpu->gd_cpuid) != 0)
565 lwkt_setcpu_self(globaldata_find(0));
570 kern_adjtime_common();
574 lwkt_setcpu_self(globaldata_find(origcpu));
578 kern_get_ntp_delta(int64_t *delta)
582 if ((origcpu = mycpu->gd_cpuid) != 0)
583 lwkt_setcpu_self(globaldata_find(0));
590 lwkt_setcpu_self(globaldata_find(origcpu));
594 kern_reladjtime(int64_t delta)
598 if ((origcpu = mycpu->gd_cpuid) != 0)
599 lwkt_setcpu_self(globaldata_find(0));
603 kern_adjtime_common();
607 lwkt_setcpu_self(globaldata_find(origcpu));
611 kern_adjfreq(int64_t rate)
615 if ((origcpu = mycpu->gd_cpuid) != 0)
616 lwkt_setcpu_self(globaldata_find(0));
619 ntp_tick_permanent = rate;
623 lwkt_setcpu_self(globaldata_find(origcpu));
630 sys_adjtime(struct adjtime_args *uap)
632 struct thread *td = curthread;
634 int64_t ndelta, odelta;
637 if ((error = priv_check(td, PRIV_ADJTIME)))
639 error = copyin(uap->delta, &atv, sizeof(struct timeval));
644 * Compute the total correction and the rate at which to apply it.
645 * Round the adjustment down to a whole multiple of the per-tick
646 * delta, so that after some number of incremental changes in
647 * hardclock(), tickdelta will become zero, lest the correction
648 * overshoot and start taking us away from the desired final time.
650 ndelta = (int64_t)atv.tv_sec * 1000000000 + atv.tv_usec * 1000;
652 kern_adjtime(ndelta, &odelta);
656 atv.tv_sec = odelta / 1000000000;
657 atv.tv_usec = odelta % 1000000000 / 1000;
658 copyout(&atv, uap->olddelta, sizeof(struct timeval));
664 sysctl_adjtime(SYSCTL_HANDLER_ARGS)
669 if (req->newptr != NULL) {
670 if (priv_check(curthread, PRIV_ROOT))
672 error = SYSCTL_IN(req, &delta, sizeof(delta));
675 kern_reladjtime(delta);
679 kern_get_ntp_delta(&delta);
680 error = SYSCTL_OUT(req, &delta, sizeof(delta));
685 * delta is in nanoseconds.
688 sysctl_delta(SYSCTL_HANDLER_ARGS)
690 int64_t delta, old_delta;
693 if (req->newptr != NULL) {
694 if (priv_check(curthread, PRIV_ROOT))
696 error = SYSCTL_IN(req, &delta, sizeof(delta));
699 kern_adjtime(delta, &old_delta);
702 if (req->oldptr != NULL)
703 kern_get_ntp_delta(&old_delta);
704 error = SYSCTL_OUT(req, &old_delta, sizeof(old_delta));
709 * frequency is in nanoseconds per second shifted left 32.
710 * kern_adjfreq() needs it in nanoseconds per tick shifted left 32.
713 sysctl_adjfreq(SYSCTL_HANDLER_ARGS)
718 if (req->newptr != NULL) {
719 if (priv_check(curthread, PRIV_ROOT))
721 error = SYSCTL_IN(req, &freqdelta, sizeof(freqdelta));
726 kern_adjfreq(freqdelta);
729 if (req->oldptr != NULL)
730 freqdelta = ntp_tick_permanent * hz;
731 error = SYSCTL_OUT(req, &freqdelta, sizeof(freqdelta));
738 SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls");
739 SYSCTL_PROC(_kern_ntp, OID_AUTO, permanent,
740 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
741 sysctl_adjfreq, "Q", "permanent correction per second");
742 SYSCTL_PROC(_kern_ntp, OID_AUTO, delta,
743 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
744 sysctl_delta, "Q", "one-time delta");
745 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD,
746 &ntp_big_delta, sizeof(ntp_big_delta), "Q",
747 "threshold for fast adjustment");
748 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD,
749 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU",
750 "per-tick adjustment");
751 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD,
752 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU",
753 "default per-tick adjustment");
754 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leap_second, CTLFLAG_RW,
755 &ntp_leap_second, sizeof(ntp_leap_second), "LU",
757 SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leap_second, CTLFLAG_RW,
758 &ntp_leap_insert, 0, "insert or remove leap second");
759 SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust,
760 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
761 sysctl_adjtime, "Q", "relative adjust for delta");
764 * Get value of an interval timer. The process virtual and
765 * profiling virtual time timers are kept in the p_stats area, since
766 * they can be swapped out. These are kept internally in the
767 * way they are specified externally: in time until they expire.
769 * The real time interval timer is kept in the process table slot
770 * for the process, and its value (it_value) is kept as an
771 * absolute time rather than as a delta, so that it is easy to keep
772 * periodic real-time signals from drifting.
774 * Virtual time timers are processed in the hardclock() routine of
775 * kern_clock.c. The real time timer is processed by a timeout
776 * routine, called from the softclock() routine. Since a callout
777 * may be delayed in real time due to interrupt processing in the system,
778 * it is possible for the real time timeout routine (realitexpire, given below),
779 * to be delayed in real time past when it is supposed to occur. It
780 * does not suffice, therefore, to reload the real timer .it_value from the
781 * real time timers .it_interval. Rather, we compute the next time in
782 * absolute time the timer should go off.
787 sys_getitimer(struct getitimer_args *uap)
789 struct proc *p = curproc;
791 struct itimerval aitv;
793 if (uap->which > ITIMER_PROF)
795 lwkt_gettoken(&p->p_token);
796 if (uap->which == ITIMER_REAL) {
798 * Convert from absolute to relative time in .it_value
799 * part of real time timer. If time for real time timer
800 * has passed return 0, else return difference between
801 * current time and time for the timer to go off.
803 aitv = p->p_realtimer;
804 if (timevalisset(&aitv.it_value)) {
805 getmicrouptime(&ctv);
806 if (timevalcmp(&aitv.it_value, &ctv, <))
807 timevalclear(&aitv.it_value);
809 timevalsub(&aitv.it_value, &ctv);
812 aitv = p->p_timer[uap->which];
814 lwkt_reltoken(&p->p_token);
815 return (copyout(&aitv, uap->itv, sizeof (struct itimerval)));
822 sys_setitimer(struct setitimer_args *uap)
824 struct itimerval aitv;
826 struct itimerval *itvp;
827 struct proc *p = curproc;
830 if (uap->which > ITIMER_PROF)
833 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
834 sizeof(struct itimerval))))
836 if ((uap->itv = uap->oitv) &&
837 (error = sys_getitimer((struct getitimer_args *)uap)))
841 if (itimerfix(&aitv.it_value))
843 if (!timevalisset(&aitv.it_value))
844 timevalclear(&aitv.it_interval);
845 else if (itimerfix(&aitv.it_interval))
847 lwkt_gettoken(&p->p_token);
848 if (uap->which == ITIMER_REAL) {
849 if (timevalisset(&p->p_realtimer.it_value))
850 callout_stop_sync(&p->p_ithandle);
851 if (timevalisset(&aitv.it_value))
852 callout_reset(&p->p_ithandle,
853 tvtohz_high(&aitv.it_value), realitexpire, p);
854 getmicrouptime(&ctv);
855 timevaladd(&aitv.it_value, &ctv);
856 p->p_realtimer = aitv;
858 p->p_timer[uap->which] = aitv;
861 p->p_flags &= ~P_SIGVTALRM;
864 p->p_flags &= ~P_SIGPROF;
868 lwkt_reltoken(&p->p_token);
873 * Real interval timer expired:
874 * send process whose timer expired an alarm signal.
875 * If time is not set up to reload, then just return.
876 * Else compute next time timer should go off which is > current time.
877 * This is where delay in processing this timeout causes multiple
878 * SIGALRM calls to be compressed into one.
879 * tvtohz_high() always adds 1 to allow for the time until the next clock
880 * interrupt being strictly less than 1 clock tick, but we don't want
881 * that here since we want to appear to be in sync with the clock
882 * interrupt even when we're delayed.
885 realitexpire(void *arg)
888 struct timeval ctv, ntv;
890 p = (struct proc *)arg;
892 lwkt_gettoken(&p->p_token);
894 if (!timevalisset(&p->p_realtimer.it_interval)) {
895 timevalclear(&p->p_realtimer.it_value);
899 timevaladd(&p->p_realtimer.it_value,
900 &p->p_realtimer.it_interval);
901 getmicrouptime(&ctv);
902 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
903 ntv = p->p_realtimer.it_value;
904 timevalsub(&ntv, &ctv);
905 callout_reset(&p->p_ithandle, tvtohz_low(&ntv),
911 lwkt_reltoken(&p->p_token);
916 * Check that a proposed value to load into the .it_value or
917 * .it_interval part of an interval timer is acceptable, and
918 * fix it to have at least minimal value (i.e. if it is less
919 * than the resolution of the clock, round it up.)
924 itimerfix(struct timeval *tv)
927 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
928 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
930 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < ustick)
931 tv->tv_usec = ustick;
936 * Decrement an interval timer by a specified number
937 * of microseconds, which must be less than a second,
938 * i.e. < 1000000. If the timer expires, then reload
939 * it. In this case, carry over (usec - old value) to
940 * reduce the value reloaded into the timer so that
941 * the timer does not drift. This routine assumes
942 * that it is called in a context where the timers
943 * on which it is operating cannot change in value.
946 itimerdecr(struct itimerval *itp, int usec)
949 if (itp->it_value.tv_usec < usec) {
950 if (itp->it_value.tv_sec == 0) {
951 /* expired, and already in next interval */
952 usec -= itp->it_value.tv_usec;
955 itp->it_value.tv_usec += 1000000;
956 itp->it_value.tv_sec--;
958 itp->it_value.tv_usec -= usec;
960 if (timevalisset(&itp->it_value))
962 /* expired, exactly at end of interval */
964 if (timevalisset(&itp->it_interval)) {
965 itp->it_value = itp->it_interval;
966 itp->it_value.tv_usec -= usec;
967 if (itp->it_value.tv_usec < 0) {
968 itp->it_value.tv_usec += 1000000;
969 itp->it_value.tv_sec--;
972 itp->it_value.tv_usec = 0; /* sec is already 0 */
977 * Add and subtract routines for timevals.
978 * N.B.: subtract routine doesn't deal with
979 * results which are before the beginning,
980 * it just gets very confused in this case.
984 timevaladd(struct timeval *t1, const struct timeval *t2)
987 t1->tv_sec += t2->tv_sec;
988 t1->tv_usec += t2->tv_usec;
993 timevalsub(struct timeval *t1, const struct timeval *t2)
996 t1->tv_sec -= t2->tv_sec;
997 t1->tv_usec -= t2->tv_usec;
1002 timevalfix(struct timeval *t1)
1005 if (t1->tv_usec < 0) {
1007 t1->tv_usec += 1000000;
1009 if (t1->tv_usec >= 1000000) {
1011 t1->tv_usec -= 1000000;
1016 * ratecheck(): simple time-based rate-limit checking.
1019 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
1021 struct timeval tv, delta;
1024 getmicrouptime(&tv); /* NB: 10ms precision */
1026 timevalsub(&delta, lasttime);
1029 * check for 0,0 is so that the message will be seen at least once,
1030 * even if interval is huge.
1032 if (timevalcmp(&delta, mininterval, >=) ||
1033 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
1042 * ppsratecheck(): packets (or events) per second limitation.
1044 * Return 0 if the limit is to be enforced (e.g. the caller
1045 * should drop a packet because of the rate limitation).
1047 * maxpps of 0 always causes zero to be returned. maxpps of -1
1048 * always causes 1 to be returned; this effectively defeats rate
1051 * Note that we maintain the struct timeval for compatibility
1052 * with other bsd systems. We reuse the storage and just monitor
1053 * clock ticks for minimal overhead.
1056 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
1061 * Reset the last time and counter if this is the first call
1062 * or more than a second has passed since the last update of
1066 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
1067 lasttime->tv_sec = now;
1069 return (maxpps != 0);
1071 (*curpps)++; /* NB: ignore potential overflow */
1072 return (maxpps < 0 || *curpps < maxpps);