The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_clock.c

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    1 /*      $NetBSD: kern_clock.c,v 1.104 2006/11/01 10:17:58 yamt Exp $    */
    2 
    3 /*-
    4  * Copyright (c) 2000, 2004 The NetBSD Foundation, Inc.
    5  * All rights reserved.
    6  *
    7  * This code is derived from software contributed to The NetBSD Foundation
    8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
    9  * NASA Ames Research Center.
   10  * This code is derived from software contributed to The NetBSD Foundation
   11  * by Charles M. Hannum.
   12  *
   13  * Redistribution and use in source and binary forms, with or without
   14  * modification, are permitted provided that the following conditions
   15  * are met:
   16  * 1. Redistributions of source code must retain the above copyright
   17  *    notice, this list of conditions and the following disclaimer.
   18  * 2. Redistributions in binary form must reproduce the above copyright
   19  *    notice, this list of conditions and the following disclaimer in the
   20  *    documentation and/or other materials provided with the distribution.
   21  * 3. All advertising materials mentioning features or use of this software
   22  *    must display the following acknowledgement:
   23  *      This product includes software developed by the NetBSD
   24  *      Foundation, Inc. and its contributors.
   25  * 4. Neither the name of The NetBSD Foundation nor the names of its
   26  *    contributors may be used to endorse or promote products derived
   27  *    from this software without specific prior written permission.
   28  *
   29  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
   30  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   31  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   32  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
   33  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   34  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   35  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   36  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   37  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   38  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   39  * POSSIBILITY OF SUCH DAMAGE.
   40  */
   41 
   42 /*-
   43  * Copyright (c) 1982, 1986, 1991, 1993
   44  *      The Regents of the University of California.  All rights reserved.
   45  * (c) UNIX System Laboratories, Inc.
   46  * All or some portions of this file are derived from material licensed
   47  * to the University of California by American Telephone and Telegraph
   48  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   49  * the permission of UNIX System Laboratories, Inc.
   50  *
   51  * Redistribution and use in source and binary forms, with or without
   52  * modification, are permitted provided that the following conditions
   53  * are met:
   54  * 1. Redistributions of source code must retain the above copyright
   55  *    notice, this list of conditions and the following disclaimer.
   56  * 2. Redistributions in binary form must reproduce the above copyright
   57  *    notice, this list of conditions and the following disclaimer in the
   58  *    documentation and/or other materials provided with the distribution.
   59  * 3. Neither the name of the University nor the names of its contributors
   60  *    may be used to endorse or promote products derived from this software
   61  *    without specific prior written permission.
   62  *
   63  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   64  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   65  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   66  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   67  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   68  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   69  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   70  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   71  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   72  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   73  * SUCH DAMAGE.
   74  *
   75  *      @(#)kern_clock.c        8.5 (Berkeley) 1/21/94
   76  */
   77 
   78 #include <sys/cdefs.h>
   79 __KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.104 2006/11/01 10:17:58 yamt Exp $");
   80 
   81 #include "opt_ntp.h"
   82 #include "opt_multiprocessor.h"
   83 #include "opt_perfctrs.h"
   84 
   85 #include <sys/param.h>
   86 #include <sys/systm.h>
   87 #include <sys/callout.h>
   88 #include <sys/kernel.h>
   89 #include <sys/proc.h>
   90 #include <sys/resourcevar.h>
   91 #include <sys/signalvar.h>
   92 #include <sys/sysctl.h>
   93 #include <sys/timex.h>
   94 #include <sys/sched.h>
   95 #include <sys/time.h>
   96 #ifdef __HAVE_TIMECOUNTER
   97 #include <sys/timetc.h>
   98 #endif
   99 
  100 #include <machine/cpu.h>
  101 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
  102 #include <machine/intr.h>
  103 #endif
  104 
  105 #ifdef GPROF
  106 #include <sys/gmon.h>
  107 #endif
  108 
  109 /*
  110  * Clock handling routines.
  111  *
  112  * This code is written to operate with two timers that run independently of
  113  * each other.  The main clock, running hz times per second, is used to keep
  114  * track of real time.  The second timer handles kernel and user profiling,
  115  * and does resource use estimation.  If the second timer is programmable,
  116  * it is randomized to avoid aliasing between the two clocks.  For example,
  117  * the randomization prevents an adversary from always giving up the CPU
  118  * just before its quantum expires.  Otherwise, it would never accumulate
  119  * CPU ticks.  The mean frequency of the second timer is stathz.
  120  *
  121  * If no second timer exists, stathz will be zero; in this case we drive
  122  * profiling and statistics off the main clock.  This WILL NOT be accurate;
  123  * do not do it unless absolutely necessary.
  124  *
  125  * The statistics clock may (or may not) be run at a higher rate while
  126  * profiling.  This profile clock runs at profhz.  We require that profhz
  127  * be an integral multiple of stathz.
  128  *
  129  * If the statistics clock is running fast, it must be divided by the ratio
  130  * profhz/stathz for statistics.  (For profiling, every tick counts.)
  131  */
  132 
  133 #ifndef __HAVE_TIMECOUNTER
  134 #ifdef NTP      /* NTP phase-locked loop in kernel */
  135 /*
  136  * Phase/frequency-lock loop (PLL/FLL) definitions
  137  *
  138  * The following variables are read and set by the ntp_adjtime() system
  139  * call.
  140  *
  141  * time_state shows the state of the system clock, with values defined
  142  * in the timex.h header file.
  143  *
  144  * time_status shows the status of the system clock, with bits defined
  145  * in the timex.h header file.
  146  *
  147  * time_offset is used by the PLL/FLL to adjust the system time in small
  148  * increments.
  149  *
  150  * time_constant determines the bandwidth or "stiffness" of the PLL.
  151  *
  152  * time_tolerance determines maximum frequency error or tolerance of the
  153  * CPU clock oscillator and is a property of the architecture; however,
  154  * in principle it could change as result of the presence of external
  155  * discipline signals, for instance.
  156  *
  157  * time_precision is usually equal to the kernel tick variable; however,
  158  * in cases where a precision clock counter or external clock is
  159  * available, the resolution can be much less than this and depend on
  160  * whether the external clock is working or not.
  161  *
  162  * time_maxerror is initialized by a ntp_adjtime() call and increased by
  163  * the kernel once each second to reflect the maximum error bound
  164  * growth.
  165  *
  166  * time_esterror is set and read by the ntp_adjtime() call, but
  167  * otherwise not used by the kernel.
  168  */
  169 int time_state = TIME_OK;       /* clock state */
  170 int time_status = STA_UNSYNC;   /* clock status bits */
  171 long time_offset = 0;           /* time offset (us) */
  172 long time_constant = 0;         /* pll time constant */
  173 long time_tolerance = MAXFREQ;  /* frequency tolerance (scaled ppm) */
  174 long time_precision = 1;        /* clock precision (us) */
  175 long time_maxerror = MAXPHASE;  /* maximum error (us) */
  176 long time_esterror = MAXPHASE;  /* estimated error (us) */
  177 
  178 /*
  179  * The following variables establish the state of the PLL/FLL and the
  180  * residual time and frequency offset of the local clock. The scale
  181  * factors are defined in the timex.h header file.
  182  *
  183  * time_phase and time_freq are the phase increment and the frequency
  184  * increment, respectively, of the kernel time variable.
  185  *
  186  * time_freq is set via ntp_adjtime() from a value stored in a file when
  187  * the synchronization daemon is first started. Its value is retrieved
  188  * via ntp_adjtime() and written to the file about once per hour by the
  189  * daemon.
  190  *
  191  * time_adj is the adjustment added to the value of tick at each timer
  192  * interrupt and is recomputed from time_phase and time_freq at each
  193  * seconds rollover.
  194  *
  195  * time_reftime is the second's portion of the system time at the last
  196  * call to ntp_adjtime(). It is used to adjust the time_freq variable
  197  * and to increase the time_maxerror as the time since last update
  198  * increases.
  199  */
  200 long time_phase = 0;            /* phase offset (scaled us) */
  201 long time_freq = 0;             /* frequency offset (scaled ppm) */
  202 long time_adj = 0;              /* tick adjust (scaled 1 / hz) */
  203 long time_reftime = 0;          /* time at last adjustment (s) */
  204 
  205 #ifdef PPS_SYNC
  206 /*
  207  * The following variables are used only if the kernel PPS discipline
  208  * code is configured (PPS_SYNC). The scale factors are defined in the
  209  * timex.h header file.
  210  *
  211  * pps_time contains the time at each calibration interval, as read by
  212  * microtime(). pps_count counts the seconds of the calibration
  213  * interval, the duration of which is nominally pps_shift in powers of
  214  * two.
  215  *
  216  * pps_offset is the time offset produced by the time median filter
  217  * pps_tf[], while pps_jitter is the dispersion (jitter) measured by
  218  * this filter.
  219  *
  220  * pps_freq is the frequency offset produced by the frequency median
  221  * filter pps_ff[], while pps_stabil is the dispersion (wander) measured
  222  * by this filter.
  223  *
  224  * pps_usec is latched from a high resolution counter or external clock
  225  * at pps_time. Here we want the hardware counter contents only, not the
  226  * contents plus the time_tv.usec as usual.
  227  *
  228  * pps_valid counts the number of seconds since the last PPS update. It
  229  * is used as a watchdog timer to disable the PPS discipline should the
  230  * PPS signal be lost.
  231  *
  232  * pps_glitch counts the number of seconds since the beginning of an
  233  * offset burst more than tick/2 from current nominal offset. It is used
  234  * mainly to suppress error bursts due to priority conflicts between the
  235  * PPS interrupt and timer interrupt.
  236  *
  237  * pps_intcnt counts the calibration intervals for use in the interval-
  238  * adaptation algorithm. It's just too complicated for words.
  239  *
  240  * pps_kc_hardpps_source contains an arbitrary value that uniquely
  241  * identifies the currently bound source of the PPS signal, or NULL
  242  * if no source is bound.
  243  *
  244  * pps_kc_hardpps_mode indicates which transitions, if any, of the PPS
  245  * signal should be reported.
  246  */
  247 struct timeval pps_time;        /* kernel time at last interval */
  248 long pps_tf[] = {0, 0, 0};      /* pps time offset median filter (us) */
  249 long pps_offset = 0;            /* pps time offset (us) */
  250 long pps_jitter = MAXTIME;      /* time dispersion (jitter) (us) */
  251 long pps_ff[] = {0, 0, 0};      /* pps frequency offset median filter */
  252 long pps_freq = 0;              /* frequency offset (scaled ppm) */
  253 long pps_stabil = MAXFREQ;      /* frequency dispersion (scaled ppm) */
  254 long pps_usec = 0;              /* microsec counter at last interval */
  255 long pps_valid = PPS_VALID;     /* pps signal watchdog counter */
  256 int pps_glitch = 0;             /* pps signal glitch counter */
  257 int pps_count = 0;              /* calibration interval counter (s) */
  258 int pps_shift = PPS_SHIFT;      /* interval duration (s) (shift) */
  259 int pps_intcnt = 0;             /* intervals at current duration */
  260 void *pps_kc_hardpps_source = NULL; /* current PPS supplier's identifier */
  261 int pps_kc_hardpps_mode = 0;    /* interesting edges of PPS signal */
  262 
  263 /*
  264  * PPS signal quality monitors
  265  *
  266  * pps_jitcnt counts the seconds that have been discarded because the
  267  * jitter measured by the time median filter exceeds the limit MAXTIME
  268  * (100 us).
  269  *
  270  * pps_calcnt counts the frequency calibration intervals, which are
  271  * variable from 4 s to 256 s.
  272  *
  273  * pps_errcnt counts the calibration intervals which have been discarded
  274  * because the wander exceeds the limit MAXFREQ (100 ppm) or where the
  275  * calibration interval jitter exceeds two ticks.
  276  *
  277  * pps_stbcnt counts the calibration intervals that have been discarded
  278  * because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
  279  */
  280 long pps_jitcnt = 0;            /* jitter limit exceeded */
  281 long pps_calcnt = 0;            /* calibration intervals */
  282 long pps_errcnt = 0;            /* calibration errors */
  283 long pps_stbcnt = 0;            /* stability limit exceeded */
  284 #endif /* PPS_SYNC */
  285 
  286 #ifdef EXT_CLOCK
  287 /*
  288  * External clock definitions
  289  *
  290  * The following definitions and declarations are used only if an
  291  * external clock is configured on the system.
  292  */
  293 #define CLOCK_INTERVAL 30       /* CPU clock update interval (s) */
  294 
  295 /*
  296  * The clock_count variable is set to CLOCK_INTERVAL at each PPS
  297  * interrupt and decremented once each second.
  298  */
  299 int clock_count = 0;            /* CPU clock counter */
  300 
  301 #ifdef HIGHBALL
  302 /*
  303  * The clock_offset and clock_cpu variables are used by the HIGHBALL
  304  * interface. The clock_offset variable defines the offset between
  305  * system time and the HIGBALL counters. The clock_cpu variable contains
  306  * the offset between the system clock and the HIGHBALL clock for use in
  307  * disciplining the kernel time variable.
  308  */
  309 extern struct timeval clock_offset; /* Highball clock offset */
  310 long clock_cpu = 0;             /* CPU clock adjust */
  311 #endif /* HIGHBALL */
  312 #endif /* EXT_CLOCK */
  313 #endif /* NTP */
  314 
  315 /*
  316  * Bump a timeval by a small number of usec's.
  317  */
  318 #define BUMPTIME(t, usec) { \
  319         volatile struct timeval *tp = (t); \
  320         long us; \
  321  \
  322         tp->tv_usec = us = tp->tv_usec + (usec); \
  323         if (us >= 1000000) { \
  324                 tp->tv_usec = us - 1000000; \
  325                 tp->tv_sec++; \
  326         } \
  327 }
  328 #endif /* !__HAVE_TIMECOUNTER */
  329 
  330 int     stathz;
  331 int     profhz;
  332 int     profsrc;
  333 int     schedhz;
  334 int     profprocs;
  335 int     hardclock_ticks;
  336 static int statscheddiv; /* stat => sched divider (used if schedhz == 0) */
  337 static int psdiv;                       /* prof => stat divider */
  338 int     psratio;                        /* ratio: prof / stat */
  339 #ifndef __HAVE_TIMECOUNTER
  340 int     tickfix, tickfixinterval;       /* used if tick not really integral */
  341 #ifndef NTP
  342 static int tickfixcnt;                  /* accumulated fractional error */
  343 #else
  344 int     fixtick;                        /* used by NTP for same */
  345 int     shifthz;
  346 #endif
  347 
  348 /*
  349  * We might want ldd to load the both words from time at once.
  350  * To succeed we need to be quadword aligned.
  351  * The sparc already does that, and that it has worked so far is a fluke.
  352  */
  353 volatile struct timeval time  __attribute__((__aligned__(__alignof__(quad_t))));
  354 volatile struct timeval mono_time;
  355 #endif /* !__HAVE_TIMECOUNTER */
  356 
  357 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
  358 void    *softclock_si;
  359 #endif
  360 
  361 #ifdef __HAVE_TIMECOUNTER
  362 static u_int get_intr_timecount(struct timecounter *);
  363 
  364 static struct timecounter intr_timecounter = {
  365         get_intr_timecount,     /* get_timecount */
  366         0,                      /* no poll_pps */
  367         ~0u,                    /* counter_mask */
  368         0,                      /* frequency */
  369         "clockinterrupt",       /* name */
  370         0,                      /* quality - minimum implementation level for a clock */
  371         NULL,                   /* prev */
  372         NULL,                   /* next */
  373 };
  374 
  375 static u_int
  376 get_intr_timecount(struct timecounter *tc)
  377 {
  378 
  379         return (u_int)hardclock_ticks;
  380 }
  381 #endif
  382 
  383 /*
  384  * Initialize clock frequencies and start both clocks running.
  385  */
  386 void
  387 initclocks(void)
  388 {
  389         int i;
  390 
  391 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
  392         softclock_si = softintr_establish(IPL_SOFTCLOCK, softclock, NULL);
  393         if (softclock_si == NULL)
  394                 panic("initclocks: unable to register softclock intr");
  395 #endif
  396 
  397         /*
  398          * Set divisors to 1 (normal case) and let the machine-specific
  399          * code do its bit.
  400          */
  401         psdiv = 1;
  402 #ifdef __HAVE_TIMECOUNTER
  403         /*
  404          * provide minimum default time counter
  405          * will only run at interrupt resolution
  406          */
  407         intr_timecounter.tc_frequency = hz;
  408         tc_init(&intr_timecounter);
  409 #endif
  410         cpu_initclocks();
  411 
  412         /*
  413          * Compute profhz/stathz/rrticks, and fix profhz if needed.
  414          */
  415         i = stathz ? stathz : hz;
  416         if (profhz == 0)
  417                 profhz = i;
  418         psratio = profhz / i;
  419         rrticks = hz / 10;
  420         if (schedhz == 0) {
  421                 /* 16Hz is best */
  422                 statscheddiv = i / 16;
  423                 if (statscheddiv <= 0)
  424                         panic("statscheddiv");
  425         }
  426 
  427 #ifndef __HAVE_TIMECOUNTER
  428 #ifdef NTP
  429         switch (hz) {
  430         case 1:
  431                 shifthz = SHIFT_SCALE - 0;
  432                 break;
  433         case 2:
  434                 shifthz = SHIFT_SCALE - 1;
  435                 break;
  436         case 4:
  437                 shifthz = SHIFT_SCALE - 2;
  438                 break;
  439         case 8:
  440                 shifthz = SHIFT_SCALE - 3;
  441                 break;
  442         case 16:
  443                 shifthz = SHIFT_SCALE - 4;
  444                 break;
  445         case 32:
  446                 shifthz = SHIFT_SCALE - 5;
  447                 break;
  448         case 50:
  449         case 60:
  450         case 64:
  451                 shifthz = SHIFT_SCALE - 6;
  452                 break;
  453         case 96:
  454         case 100:
  455         case 128:
  456                 shifthz = SHIFT_SCALE - 7;
  457                 break;
  458         case 256:
  459                 shifthz = SHIFT_SCALE - 8;
  460                 break;
  461         case 512:
  462                 shifthz = SHIFT_SCALE - 9;
  463                 break;
  464         case 1000:
  465         case 1024:
  466                 shifthz = SHIFT_SCALE - 10;
  467                 break;
  468         case 1200:
  469         case 2048:
  470                 shifthz = SHIFT_SCALE - 11;
  471                 break;
  472         case 4096:
  473                 shifthz = SHIFT_SCALE - 12;
  474                 break;
  475         case 8192:
  476                 shifthz = SHIFT_SCALE - 13;
  477                 break;
  478         case 16384:
  479                 shifthz = SHIFT_SCALE - 14;
  480                 break;
  481         case 32768:
  482                 shifthz = SHIFT_SCALE - 15;
  483                 break;
  484         case 65536:
  485                 shifthz = SHIFT_SCALE - 16;
  486                 break;
  487         default:
  488                 panic("weird hz");
  489         }
  490         if (fixtick == 0) {
  491                 /*
  492                  * Give MD code a chance to set this to a better
  493                  * value; but, if it doesn't, we should.
  494                  */
  495                 fixtick = (1000000 - (hz*tick));
  496         }
  497 #endif /* NTP */
  498 #endif /* !__HAVE_TIMECOUNTER */
  499 }
  500 
  501 /*
  502  * The real-time timer, interrupting hz times per second.
  503  */
  504 void
  505 hardclock(struct clockframe *frame)
  506 {
  507         struct lwp *l;
  508         struct proc *p;
  509         struct cpu_info *ci = curcpu();
  510         struct ptimer *pt;
  511 #ifndef __HAVE_TIMECOUNTER
  512         int delta;
  513         extern int tickdelta;
  514         extern long timedelta;
  515 #ifdef NTP
  516         int time_update;
  517         int ltemp;
  518 #endif /* NTP */
  519 #endif /* __HAVE_TIMECOUNTER */
  520 
  521         l = curlwp;
  522         if (l) {
  523                 p = l->l_proc;
  524                 /*
  525                  * Run current process's virtual and profile time, as needed.
  526                  */
  527                 if (CLKF_USERMODE(frame) && p->p_timers &&
  528                     (pt = LIST_FIRST(&p->p_timers->pts_virtual)) != NULL)
  529                         if (itimerdecr(pt, tick) == 0)
  530                                 itimerfire(pt);
  531                 if (p->p_timers &&
  532                     (pt = LIST_FIRST(&p->p_timers->pts_prof)) != NULL)
  533                         if (itimerdecr(pt, tick) == 0)
  534                                 itimerfire(pt);
  535         }
  536 
  537         /*
  538          * If no separate statistics clock is available, run it from here.
  539          */
  540         if (stathz == 0)
  541                 statclock(frame);
  542         if ((--ci->ci_schedstate.spc_rrticks) <= 0)
  543                 roundrobin(ci);
  544 
  545 #if defined(MULTIPROCESSOR)
  546         /*
  547          * If we are not the primary CPU, we're not allowed to do
  548          * any more work.
  549          */
  550         if (CPU_IS_PRIMARY(ci) == 0)
  551                 return;
  552 #endif
  553 
  554         hardclock_ticks++;
  555 
  556 #ifdef __HAVE_TIMECOUNTER
  557         tc_ticktock();
  558 #else /* __HAVE_TIMECOUNTER */
  559         /*
  560          * Increment the time-of-day.  The increment is normally just
  561          * ``tick''.  If the machine is one which has a clock frequency
  562          * such that ``hz'' would not divide the second evenly into
  563          * milliseconds, a periodic adjustment must be applied.  Finally,
  564          * if we are still adjusting the time (see adjtime()),
  565          * ``tickdelta'' may also be added in.
  566          */
  567         delta = tick;
  568 
  569 #ifndef NTP
  570         if (tickfix) {
  571                 tickfixcnt += tickfix;
  572                 if (tickfixcnt >= tickfixinterval) {
  573                         delta++;
  574                         tickfixcnt -= tickfixinterval;
  575                 }
  576         }
  577 #endif /* !NTP */
  578         /* Imprecise 4bsd adjtime() handling */
  579         if (timedelta != 0) {
  580                 delta += tickdelta;
  581                 timedelta -= tickdelta;
  582         }
  583 
  584 #ifdef notyet
  585         microset();
  586 #endif
  587 
  588 #ifndef NTP
  589         BUMPTIME(&time, delta);         /* XXX Now done using NTP code below */
  590 #endif
  591         BUMPTIME(&mono_time, delta);
  592 
  593 #ifdef NTP
  594         time_update = delta;
  595 
  596         /*
  597          * Compute the phase adjustment. If the low-order bits
  598          * (time_phase) of the update overflow, bump the high-order bits
  599          * (time_update).
  600          */
  601         time_phase += time_adj;
  602         if (time_phase <= -FINEUSEC) {
  603                 ltemp = -time_phase >> SHIFT_SCALE;
  604                 time_phase += ltemp << SHIFT_SCALE;
  605                 time_update -= ltemp;
  606         } else if (time_phase >= FINEUSEC) {
  607                 ltemp = time_phase >> SHIFT_SCALE;
  608                 time_phase -= ltemp << SHIFT_SCALE;
  609                 time_update += ltemp;
  610         }
  611 
  612 #ifdef HIGHBALL
  613         /*
  614          * If the HIGHBALL board is installed, we need to adjust the
  615          * external clock offset in order to close the hardware feedback
  616          * loop. This will adjust the external clock phase and frequency
  617          * in small amounts. The additional phase noise and frequency
  618          * wander this causes should be minimal. We also need to
  619          * discipline the kernel time variable, since the PLL is used to
  620          * discipline the external clock. If the Highball board is not
  621          * present, we discipline kernel time with the PLL as usual. We
  622          * assume that the external clock phase adjustment (time_update)
  623          * and kernel phase adjustment (clock_cpu) are less than the
  624          * value of tick.
  625          */
  626         clock_offset.tv_usec += time_update;
  627         if (clock_offset.tv_usec >= 1000000) {
  628                 clock_offset.tv_sec++;
  629                 clock_offset.tv_usec -= 1000000;
  630         }
  631         if (clock_offset.tv_usec < 0) {
  632                 clock_offset.tv_sec--;
  633                 clock_offset.tv_usec += 1000000;
  634         }
  635         time.tv_usec += clock_cpu;
  636         clock_cpu = 0;
  637 #else
  638         time.tv_usec += time_update;
  639 #endif /* HIGHBALL */
  640 
  641         /*
  642          * On rollover of the second the phase adjustment to be used for
  643          * the next second is calculated. Also, the maximum error is
  644          * increased by the tolerance. If the PPS frequency discipline
  645          * code is present, the phase is increased to compensate for the
  646          * CPU clock oscillator frequency error.
  647          *
  648          * On a 32-bit machine and given parameters in the timex.h
  649          * header file, the maximum phase adjustment is +-512 ms and
  650          * maximum frequency offset is a tad less than) +-512 ppm. On a
  651          * 64-bit machine, you shouldn't need to ask.
  652          */
  653         if (time.tv_usec >= 1000000) {
  654                 time.tv_usec -= 1000000;
  655                 time.tv_sec++;
  656                 time_maxerror += time_tolerance >> SHIFT_USEC;
  657 
  658                 /*
  659                  * Leap second processing. If in leap-insert state at
  660                  * the end of the day, the system clock is set back one
  661                  * second; if in leap-delete state, the system clock is
  662                  * set ahead one second. The microtime() routine or
  663                  * external clock driver will insure that reported time
  664                  * is always monotonic. The ugly divides should be
  665                  * replaced.
  666                  */
  667                 switch (time_state) {
  668                 case TIME_OK:
  669                         if (time_status & STA_INS)
  670                                 time_state = TIME_INS;
  671                         else if (time_status & STA_DEL)
  672                                 time_state = TIME_DEL;
  673                         break;
  674 
  675                 case TIME_INS:
  676                         if (time.tv_sec % 86400 == 0) {
  677                                 time.tv_sec--;
  678                                 time_state = TIME_OOP;
  679                         }
  680                         break;
  681 
  682                 case TIME_DEL:
  683                         if ((time.tv_sec + 1) % 86400 == 0) {
  684                                 time.tv_sec++;
  685                                 time_state = TIME_WAIT;
  686                         }
  687                         break;
  688 
  689                 case TIME_OOP:
  690                         time_state = TIME_WAIT;
  691                         break;
  692 
  693                 case TIME_WAIT:
  694                         if (!(time_status & (STA_INS | STA_DEL)))
  695                                 time_state = TIME_OK;
  696                         break;
  697                 }
  698 
  699                 /*
  700                  * Compute the phase adjustment for the next second. In
  701                  * PLL mode, the offset is reduced by a fixed factor
  702                  * times the time constant. In FLL mode the offset is
  703                  * used directly. In either mode, the maximum phase
  704                  * adjustment for each second is clamped so as to spread
  705                  * the adjustment over not more than the number of
  706                  * seconds between updates.
  707                  */
  708                 if (time_offset < 0) {
  709                         ltemp = -time_offset;
  710                         if (!(time_status & STA_FLL))
  711                                 ltemp >>= SHIFT_KG + time_constant;
  712                         if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
  713                                 ltemp = (MAXPHASE / MINSEC) <<
  714                                     SHIFT_UPDATE;
  715                         time_offset += ltemp;
  716                         time_adj = -ltemp << (shifthz - SHIFT_UPDATE);
  717                 } else if (time_offset > 0) {
  718                         ltemp = time_offset;
  719                         if (!(time_status & STA_FLL))
  720                                 ltemp >>= SHIFT_KG + time_constant;
  721                         if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
  722                                 ltemp = (MAXPHASE / MINSEC) <<
  723                                     SHIFT_UPDATE;
  724                         time_offset -= ltemp;
  725                         time_adj = ltemp << (shifthz - SHIFT_UPDATE);
  726                 } else
  727                         time_adj = 0;
  728 
  729                 /*
  730                  * Compute the frequency estimate and additional phase
  731                  * adjustment due to frequency error for the next
  732                  * second. When the PPS signal is engaged, gnaw on the
  733                  * watchdog counter and update the frequency computed by
  734                  * the pll and the PPS signal.
  735                  */
  736 #ifdef PPS_SYNC
  737                 pps_valid++;
  738                 if (pps_valid == PPS_VALID) {
  739                         pps_jitter = MAXTIME;
  740                         pps_stabil = MAXFREQ;
  741                         time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
  742                             STA_PPSWANDER | STA_PPSERROR);
  743                 }
  744                 ltemp = time_freq + pps_freq;
  745 #else
  746                 ltemp = time_freq;
  747 #endif /* PPS_SYNC */
  748 
  749                 if (ltemp < 0)
  750                         time_adj -= -ltemp >> (SHIFT_USEC - shifthz);
  751                 else
  752                         time_adj += ltemp >> (SHIFT_USEC - shifthz);
  753                 time_adj += (long)fixtick << shifthz;
  754 
  755                 /*
  756                  * When the CPU clock oscillator frequency is not a
  757                  * power of 2 in Hz, shifthz is only an approximate
  758                  * scale factor.
  759                  *
  760                  * To determine the adjustment, you can do the following:
  761                  *   bc -q
  762                  *   scale=24
  763                  *   obase=2
  764                  *   idealhz/realhz
  765                  * where `idealhz' is the next higher power of 2, and `realhz'
  766                  * is the actual value.  You may need to factor this result
  767                  * into a sequence of 2 multipliers to get better precision.
  768                  *
  769                  * Likewise, the error can be calculated with (e.g. for 100Hz):
  770                  *   bc -q
  771                  *   scale=24
  772                  *   ((1+2^-2+2^-5)*(1-2^-10)*realhz-idealhz)/idealhz
  773                  * (and then multiply by 1000000 to get ppm).
  774                  */
  775                 switch (hz) {
  776                 case 60:
  777                         /* A factor of 1.000100010001 gives about 15ppm
  778                            error. */
  779                         if (time_adj < 0) {
  780                                 time_adj -= (-time_adj >> 4);
  781                                 time_adj -= (-time_adj >> 8);
  782                         } else {
  783                                 time_adj += (time_adj >> 4);
  784                                 time_adj += (time_adj >> 8);
  785                         }
  786                         break;
  787 
  788                 case 96:
  789                         /* A factor of 1.0101010101 gives about 244ppm error. */
  790                         if (time_adj < 0) {
  791                                 time_adj -= (-time_adj >> 2);
  792                                 time_adj -= (-time_adj >> 4) + (-time_adj >> 8);
  793                         } else {
  794                                 time_adj += (time_adj >> 2);
  795                                 time_adj += (time_adj >> 4) + (time_adj >> 8);
  796                         }
  797                         break;
  798 
  799                 case 50:
  800                 case 100:
  801                         /* A factor of 1.010001111010111 gives about 1ppm
  802                            error. */
  803                         if (time_adj < 0) {
  804                                 time_adj -= (-time_adj >> 2) + (-time_adj >> 5);
  805                                 time_adj += (-time_adj >> 10);
  806                         } else {
  807                                 time_adj += (time_adj >> 2) + (time_adj >> 5);
  808                                 time_adj -= (time_adj >> 10);
  809                         }
  810                         break;
  811 
  812                 case 1000:
  813                         /* A factor of 1.000001100010100001 gives about 50ppm
  814                            error. */
  815                         if (time_adj < 0) {
  816                                 time_adj -= (-time_adj >> 6) + (-time_adj >> 11);
  817                                 time_adj -= (-time_adj >> 7);
  818                         } else {
  819                                 time_adj += (time_adj >> 6) + (time_adj >> 11);
  820                                 time_adj += (time_adj >> 7);
  821                         }
  822                         break;
  823 
  824                 case 1200:
  825                         /* A factor of 1.1011010011100001 gives about 64ppm
  826                            error. */
  827                         if (time_adj < 0) {
  828                                 time_adj -= (-time_adj >> 1) + (-time_adj >> 6);
  829                                 time_adj -= (-time_adj >> 3) + (-time_adj >> 10);
  830                         } else {
  831                                 time_adj += (time_adj >> 1) + (time_adj >> 6);
  832                                 time_adj += (time_adj >> 3) + (time_adj >> 10);
  833                         }
  834                         break;
  835                 }
  836 
  837 #ifdef EXT_CLOCK
  838                 /*
  839                  * If an external clock is present, it is necessary to
  840                  * discipline the kernel time variable anyway, since not
  841                  * all system components use the microtime() interface.
  842                  * Here, the time offset between the external clock and
  843                  * kernel time variable is computed every so often.
  844                  */
  845                 clock_count++;
  846                 if (clock_count > CLOCK_INTERVAL) {
  847                         clock_count = 0;
  848                         microtime(&clock_ext);
  849                         delta.tv_sec = clock_ext.tv_sec - time.tv_sec;
  850                         delta.tv_usec = clock_ext.tv_usec -
  851                             time.tv_usec;
  852                         if (delta.tv_usec < 0)
  853                                 delta.tv_sec--;
  854                         if (delta.tv_usec >= 500000) {
  855                                 delta.tv_usec -= 1000000;
  856                                 delta.tv_sec++;
  857                         }
  858                         if (delta.tv_usec < -500000) {
  859                                 delta.tv_usec += 1000000;
  860                                 delta.tv_sec--;
  861                         }
  862                         if (delta.tv_sec > 0 || (delta.tv_sec == 0 &&
  863                             delta.tv_usec > MAXPHASE) ||
  864                             delta.tv_sec < -1 || (delta.tv_sec == -1 &&
  865                             delta.tv_usec < -MAXPHASE)) {
  866                                 time = clock_ext;
  867                                 delta.tv_sec = 0;
  868                                 delta.tv_usec = 0;
  869                         }
  870 #ifdef HIGHBALL
  871                         clock_cpu = delta.tv_usec;
  872 #else /* HIGHBALL */
  873                         hardupdate(delta.tv_usec);
  874 #endif /* HIGHBALL */
  875                 }
  876 #endif /* EXT_CLOCK */
  877         }
  878 
  879 #endif /* NTP */
  880 #endif /* !__HAVE_TIMECOUNTER */
  881 
  882         /*
  883          * Update real-time timeout queue.
  884          * Process callouts at a very low CPU priority, so we don't keep the
  885          * relatively high clock interrupt priority any longer than necessary.
  886          */
  887         if (callout_hardclock()) {
  888                 if (CLKF_BASEPRI(frame)) {
  889                         /*
  890                          * Save the overhead of a software interrupt;
  891                          * it will happen as soon as we return, so do
  892                          * it now.
  893                          */
  894                         spllowersoftclock();
  895                         KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE);
  896                         softclock(NULL);
  897                         KERNEL_UNLOCK();
  898                 } else {
  899 #ifdef __HAVE_GENERIC_SOFT_INTERRUPTS
  900                         softintr_schedule(softclock_si);
  901 #else
  902                         setsoftclock();
  903 #endif
  904                 }
  905         }
  906 }
  907 
  908 #ifdef __HAVE_TIMECOUNTER
  909 /*
  910  * Compute number of hz until specified time.  Used to compute second
  911  * argument to callout_reset() from an absolute time.
  912  */
  913 int
  914 hzto(struct timeval *tvp)
  915 {
  916         struct timeval now, tv;
  917 
  918         tv = *tvp;      /* Don't modify original tvp. */
  919         getmicrotime(&now);
  920         timersub(&tv, &now, &tv);
  921         return tvtohz(&tv);
  922 }
  923 #endif /* __HAVE_TIMECOUNTER */
  924 
  925 /*
  926  * Compute number of ticks in the specified amount of time.
  927  */
  928 int
  929 tvtohz(struct timeval *tv)
  930 {
  931         unsigned long ticks;
  932         long sec, usec;
  933 
  934         /*
  935          * If the number of usecs in the whole seconds part of the time
  936          * difference fits in a long, then the total number of usecs will
  937          * fit in an unsigned long.  Compute the total and convert it to
  938          * ticks, rounding up and adding 1 to allow for the current tick
  939          * to expire.  Rounding also depends on unsigned long arithmetic
  940          * to avoid overflow.
  941          *
  942          * Otherwise, if the number of ticks in the whole seconds part of
  943          * the time difference fits in a long, then convert the parts to
  944          * ticks separately and add, using similar rounding methods and
  945          * overflow avoidance.  This method would work in the previous
  946          * case, but it is slightly slower and assumes that hz is integral.
  947          *
  948          * Otherwise, round the time difference down to the maximum
  949          * representable value.
  950          *
  951          * If ints are 32-bit, then the maximum value for any timeout in
  952          * 10ms ticks is 248 days.
  953          */
  954         sec = tv->tv_sec;
  955         usec = tv->tv_usec;
  956 
  957         if (usec < 0) {
  958                 sec--;
  959                 usec += 1000000;
  960         }
  961 
  962         if (sec < 0 || (sec == 0 && usec <= 0)) {
  963                 /*
  964                  * Would expire now or in the past.  Return 0 ticks.
  965                  * This is different from the legacy hzto() interface,
  966                  * and callers need to check for it.
  967                  */
  968                 ticks = 0;
  969         } else if (sec <= (LONG_MAX / 1000000))
  970                 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1))
  971                     / tick) + 1;
  972         else if (sec <= (LONG_MAX / hz))
  973                 ticks = (sec * hz) +
  974                     (((unsigned long)usec + (tick - 1)) / tick) + 1;
  975         else
  976                 ticks = LONG_MAX;
  977 
  978         if (ticks > INT_MAX)
  979                 ticks = INT_MAX;
  980 
  981         return ((int)ticks);
  982 }
  983 
  984 #ifndef __HAVE_TIMECOUNTER
  985 /*
  986  * Compute number of hz until specified time.  Used to compute second
  987  * argument to callout_reset() from an absolute time.
  988  */
  989 int
  990 hzto(struct timeval *tv)
  991 {
  992         unsigned long ticks;
  993         long sec, usec;
  994         int s;
  995 
  996         /*
  997          * If the number of usecs in the whole seconds part of the time
  998          * difference fits in a long, then the total number of usecs will
  999          * fit in an unsigned long.  Compute the total and convert it to
 1000          * ticks, rounding up and adding 1 to allow for the current tick
 1001          * to expire.  Rounding also depends on unsigned long arithmetic
 1002          * to avoid overflow.
 1003          *
 1004          * Otherwise, if the number of ticks in the whole seconds part of
 1005          * the time difference fits in a long, then convert the parts to
 1006          * ticks separately and add, using similar rounding methods and
 1007          * overflow avoidance.  This method would work in the previous
 1008          * case, but it is slightly slower and assume that hz is integral.
 1009          *
 1010          * Otherwise, round the time difference down to the maximum
 1011          * representable value.
 1012          *
 1013          * If ints are 32-bit, then the maximum value for any timeout in
 1014          * 10ms ticks is 248 days.
 1015          */
 1016         s = splclock();
 1017         sec = tv->tv_sec - time.tv_sec;
 1018         usec = tv->tv_usec - time.tv_usec;
 1019         splx(s);
 1020 
 1021         if (usec < 0) {
 1022                 sec--;
 1023                 usec += 1000000;
 1024         }
 1025 
 1026         if (sec < 0 || (sec == 0 && usec <= 0)) {
 1027                 /*
 1028                  * Would expire now or in the past.  Return 0 ticks.
 1029                  * This is different from the legacy hzto() interface,
 1030                  * and callers need to check for it.
 1031                  */
 1032                 ticks = 0;
 1033         } else if (sec <= (LONG_MAX / 1000000))
 1034                 ticks = (((sec * 1000000) + (unsigned long)usec + (tick - 1))
 1035                     / tick) + 1;
 1036         else if (sec <= (LONG_MAX / hz))
 1037                 ticks = (sec * hz) +
 1038                     (((unsigned long)usec + (tick - 1)) / tick) + 1;
 1039         else
 1040                 ticks = LONG_MAX;
 1041 
 1042         if (ticks > INT_MAX)
 1043                 ticks = INT_MAX;
 1044 
 1045         return ((int)ticks);
 1046 }
 1047 #endif /* !__HAVE_TIMECOUNTER */
 1048 
 1049 /*
 1050  * Compute number of ticks in the specified amount of time.
 1051  */
 1052 int
 1053 tstohz(struct timespec *ts)
 1054 {
 1055         struct timeval tv;
 1056 
 1057         /*
 1058          * usec has great enough resolution for hz, so convert to a
 1059          * timeval and use tvtohz() above.
 1060          */
 1061         TIMESPEC_TO_TIMEVAL(&tv, ts);
 1062         return tvtohz(&tv);
 1063 }
 1064 
 1065 /*
 1066  * Start profiling on a process.
 1067  *
 1068  * Kernel profiling passes proc0 which never exits and hence
 1069  * keeps the profile clock running constantly.
 1070  */
 1071 void
 1072 startprofclock(struct proc *p)
 1073 {
 1074 
 1075         if ((p->p_flag & P_PROFIL) == 0) {
 1076                 p->p_flag |= P_PROFIL;
 1077                 /*
 1078                  * This is only necessary if using the clock as the
 1079                  * profiling source.
 1080                  */
 1081                 if (++profprocs == 1 && stathz != 0)
 1082                         psdiv = psratio;
 1083         }
 1084 }
 1085 
 1086 /*
 1087  * Stop profiling on a process.
 1088  */
 1089 void
 1090 stopprofclock(struct proc *p)
 1091 {
 1092 
 1093         if (p->p_flag & P_PROFIL) {
 1094                 p->p_flag &= ~P_PROFIL;
 1095                 /*
 1096                  * This is only necessary if using the clock as the
 1097                  * profiling source.
 1098                  */
 1099                 if (--profprocs == 0 && stathz != 0)
 1100                         psdiv = 1;
 1101         }
 1102 }
 1103 
 1104 #if defined(PERFCTRS)
 1105 /*
 1106  * Independent profiling "tick" in case we're using a separate
 1107  * clock or profiling event source.  Currently, that's just
 1108  * performance counters--hence the wrapper.
 1109  */
 1110 void
 1111 proftick(struct clockframe *frame)
 1112 {
 1113 #ifdef GPROF
 1114         struct gmonparam *g;
 1115         intptr_t i;
 1116 #endif
 1117         struct proc *p;
 1118 
 1119         p = curproc;
 1120         if (CLKF_USERMODE(frame)) {
 1121                 if (p->p_flag & P_PROFIL)
 1122                         addupc_intr(p, CLKF_PC(frame));
 1123         } else {
 1124 #ifdef GPROF
 1125                 g = &_gmonparam;
 1126                 if (g->state == GMON_PROF_ON) {
 1127                         i = CLKF_PC(frame) - g->lowpc;
 1128                         if (i < g->textsize) {
 1129                                 i /= HISTFRACTION * sizeof(*g->kcount);
 1130                                 g->kcount[i]++;
 1131                         }
 1132                 }
 1133 #endif
 1134 #ifdef PROC_PC
 1135                 if (p && (p->p_flag & P_PROFIL))
 1136                         addupc_intr(p, PROC_PC(p));
 1137 #endif
 1138         }
 1139 }
 1140 #endif
 1141 
 1142 /*
 1143  * Statistics clock.  Grab profile sample, and if divider reaches 0,
 1144  * do process and kernel statistics.
 1145  */
 1146 void
 1147 statclock(struct clockframe *frame)
 1148 {
 1149 #ifdef GPROF
 1150         struct gmonparam *g;
 1151         intptr_t i;
 1152 #endif
 1153         struct cpu_info *ci = curcpu();
 1154         struct schedstate_percpu *spc = &ci->ci_schedstate;
 1155         struct proc *p;
 1156         struct lwp *l;
 1157 
 1158         /*
 1159          * Notice changes in divisor frequency, and adjust clock
 1160          * frequency accordingly.
 1161          */
 1162         if (spc->spc_psdiv != psdiv) {
 1163                 spc->spc_psdiv = psdiv;
 1164                 spc->spc_pscnt = psdiv;
 1165                 if (psdiv == 1) {
 1166                         setstatclockrate(stathz);
 1167                 } else {
 1168                         setstatclockrate(profhz);
 1169                 }
 1170         }
 1171         l = curlwp;
 1172         p = (l ? l->l_proc : NULL);
 1173         if (CLKF_USERMODE(frame)) {
 1174                 KASSERT(p != NULL);
 1175 
 1176                 if ((p->p_flag & P_PROFIL) && profsrc == PROFSRC_CLOCK)
 1177                         addupc_intr(p, CLKF_PC(frame));
 1178                 if (--spc->spc_pscnt > 0)
 1179                         return;
 1180                 /*
 1181                  * Came from user mode; CPU was in user state.
 1182                  * If this process is being profiled record the tick.
 1183                  */
 1184                 p->p_uticks++;
 1185                 if (p->p_nice > NZERO)
 1186                         spc->spc_cp_time[CP_NICE]++;
 1187                 else
 1188                         spc->spc_cp_time[CP_USER]++;
 1189         } else {
 1190 #ifdef GPROF
 1191                 /*
 1192                  * Kernel statistics are just like addupc_intr, only easier.
 1193                  */
 1194                 g = &_gmonparam;
 1195                 if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) {
 1196                         i = CLKF_PC(frame) - g->lowpc;
 1197                         if (i < g->textsize) {
 1198                                 i /= HISTFRACTION * sizeof(*g->kcount);
 1199                                 g->kcount[i]++;
 1200                         }
 1201                 }
 1202 #endif
 1203 #ifdef LWP_PC
 1204                 if (p && profsrc == PROFSRC_CLOCK && (p->p_flag & P_PROFIL))
 1205                         addupc_intr(p, LWP_PC(l));
 1206 #endif
 1207                 if (--spc->spc_pscnt > 0)
 1208                         return;
 1209                 /*
 1210                  * Came from kernel mode, so we were:
 1211                  * - handling an interrupt,
 1212                  * - doing syscall or trap work on behalf of the current
 1213                  *   user process, or
 1214                  * - spinning in the idle loop.
 1215                  * Whichever it is, charge the time as appropriate.
 1216                  * Note that we charge interrupts to the current process,
 1217                  * regardless of whether they are ``for'' that process,
 1218                  * so that we know how much of its real time was spent
 1219                  * in ``non-process'' (i.e., interrupt) work.
 1220                  */
 1221                 if (CLKF_INTR(frame)) {
 1222                         if (p != NULL)
 1223                                 p->p_iticks++;
 1224                         spc->spc_cp_time[CP_INTR]++;
 1225                 } else if (p != NULL) {
 1226                         p->p_sticks++;
 1227                         spc->spc_cp_time[CP_SYS]++;
 1228                 } else
 1229                         spc->spc_cp_time[CP_IDLE]++;
 1230         }
 1231         spc->spc_pscnt = psdiv;
 1232 
 1233         if (p != NULL) {
 1234                 ++p->p_cpticks;
 1235                 /*
 1236                  * If no separate schedclock is provided, call it here
 1237                  * at about 16 Hz.
 1238                  */
 1239                 if (schedhz == 0)
 1240                         if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) {
 1241                                 schedclock(l);
 1242                                 ci->ci_schedstate.spc_schedticks = statscheddiv;
 1243                         }
 1244         }
 1245 }
 1246 
 1247 #ifndef __HAVE_TIMECOUNTER
 1248 #ifdef NTP      /* NTP phase-locked loop in kernel */
 1249 /*
 1250  * hardupdate() - local clock update
 1251  *
 1252  * This routine is called by ntp_adjtime() to update the local clock
 1253  * phase and frequency. The implementation is of an adaptive-parameter,
 1254  * hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
 1255  * time and frequency offset estimates for each call. If the kernel PPS
 1256  * discipline code is configured (PPS_SYNC), the PPS signal itself
 1257  * determines the new time offset, instead of the calling argument.
 1258  * Presumably, calls to ntp_adjtime() occur only when the caller
 1259  * believes the local clock is valid within some bound (+-128 ms with
 1260  * NTP). If the caller's time is far different than the PPS time, an
 1261  * argument will ensue, and it's not clear who will lose.
 1262  *
 1263  * For uncompensated quartz crystal oscillatores and nominal update
 1264  * intervals less than 1024 s, operation should be in phase-lock mode
 1265  * (STA_FLL = 0), where the loop is disciplined to phase. For update
 1266  * intervals greater than thiss, operation should be in frequency-lock
 1267  * mode (STA_FLL = 1), where the loop is disciplined to frequency.
 1268  *
 1269  * Note: splclock() is in effect.
 1270  */
 1271 void
 1272 hardupdate(long offset)
 1273 {
 1274         long ltemp, mtemp;
 1275 
 1276         if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
 1277                 return;
 1278         ltemp = offset;
 1279 #ifdef PPS_SYNC
 1280         if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
 1281                 ltemp = pps_offset;
 1282 #endif /* PPS_SYNC */
 1283 
 1284         /*
 1285          * Scale the phase adjustment and clamp to the operating range.
 1286          */
 1287         if (ltemp > MAXPHASE)
 1288                 time_offset = MAXPHASE << SHIFT_UPDATE;
 1289         else if (ltemp < -MAXPHASE)
 1290                 time_offset = -(MAXPHASE << SHIFT_UPDATE);
 1291         else
 1292                 time_offset = ltemp << SHIFT_UPDATE;
 1293 
 1294         /*
 1295          * Select whether the frequency is to be controlled and in which
 1296          * mode (PLL or FLL). Clamp to the operating range. Ugly
 1297          * multiply/divide should be replaced someday.
 1298          */
 1299         if (time_status & STA_FREQHOLD || time_reftime == 0)
 1300                 time_reftime = time.tv_sec;
 1301         mtemp = time.tv_sec - time_reftime;
 1302         time_reftime = time.tv_sec;
 1303         if (time_status & STA_FLL) {
 1304                 if (mtemp >= MINSEC) {
 1305                         ltemp = ((time_offset / mtemp) << (SHIFT_USEC -
 1306                             SHIFT_UPDATE));
 1307                         if (ltemp < 0)
 1308                                 time_freq -= -ltemp >> SHIFT_KH;
 1309                         else
 1310                                 time_freq += ltemp >> SHIFT_KH;
 1311                 }
 1312         } else {
 1313                 if (mtemp < MAXSEC) {
 1314                         ltemp *= mtemp;
 1315                         if (ltemp < 0)
 1316                                 time_freq -= -ltemp >> (time_constant +
 1317                                     time_constant + SHIFT_KF -
 1318                                     SHIFT_USEC);
 1319                         else
 1320                                 time_freq += ltemp >> (time_constant +
 1321                                     time_constant + SHIFT_KF -
 1322                                     SHIFT_USEC);
 1323                 }
 1324         }
 1325         if (time_freq > time_tolerance)
 1326                 time_freq = time_tolerance;
 1327         else if (time_freq < -time_tolerance)
 1328                 time_freq = -time_tolerance;
 1329 }
 1330 
 1331 #ifdef PPS_SYNC
 1332 /*
 1333  * hardpps() - discipline CPU clock oscillator to external PPS signal
 1334  *
 1335  * This routine is called at each PPS interrupt in order to discipline
 1336  * the CPU clock oscillator to the PPS signal. It measures the PPS phase
 1337  * and leaves it in a handy spot for the hardclock() routine. It
 1338  * integrates successive PPS phase differences and calculates the
 1339  * frequency offset. This is used in hardclock() to discipline the CPU
 1340  * clock oscillator so that intrinsic frequency error is cancelled out.
 1341  * The code requires the caller to capture the time and hardware counter
 1342  * value at the on-time PPS signal transition.
 1343  *
 1344  * Note that, on some Unix systems, this routine runs at an interrupt
 1345  * priority level higher than the timer interrupt routine hardclock().
 1346  * Therefore, the variables used are distinct from the hardclock()
 1347  * variables, except for certain exceptions: The PPS frequency pps_freq
 1348  * and phase pps_offset variables are determined by this routine and
 1349  * updated atomically. The time_tolerance variable can be considered a
 1350  * constant, since it is infrequently changed, and then only when the
 1351  * PPS signal is disabled. The watchdog counter pps_valid is updated
 1352  * once per second by hardclock() and is atomically cleared in this
 1353  * routine.
 1354  */
 1355 void
 1356 hardpps(struct timeval *tvp,            /* time at PPS */
 1357         long usec                       /* hardware counter at PPS */)
 1358 {
 1359         long u_usec, v_usec, bigtick;
 1360         long cal_sec, cal_usec;
 1361 
 1362         /*
 1363          * An occasional glitch can be produced when the PPS interrupt
 1364          * occurs in the hardclock() routine before the time variable is
 1365          * updated. Here the offset is discarded when the difference
 1366          * between it and the last one is greater than tick/2, but not
 1367          * if the interval since the first discard exceeds 30 s.
 1368          */
 1369         time_status |= STA_PPSSIGNAL;
 1370         time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
 1371         pps_valid = 0;
 1372         u_usec = -tvp->tv_usec;
 1373         if (u_usec < -500000)
 1374                 u_usec += 1000000;
 1375         v_usec = pps_offset - u_usec;
 1376         if (v_usec < 0)
 1377                 v_usec = -v_usec;
 1378         if (v_usec > (tick >> 1)) {
 1379                 if (pps_glitch > MAXGLITCH) {
 1380                         pps_glitch = 0;
 1381                         pps_tf[2] = u_usec;
 1382                         pps_tf[1] = u_usec;
 1383                 } else {
 1384                         pps_glitch++;
 1385                         u_usec = pps_offset;
 1386                 }
 1387         } else
 1388                 pps_glitch = 0;
 1389 
 1390         /*
 1391          * A three-stage median filter is used to help deglitch the pps
 1392          * time. The median sample becomes the time offset estimate; the
 1393          * difference between the other two samples becomes the time
 1394          * dispersion (jitter) estimate.
 1395          */
 1396         pps_tf[2] = pps_tf[1];
 1397         pps_tf[1] = pps_tf[0];
 1398         pps_tf[0] = u_usec;
 1399         if (pps_tf[0] > pps_tf[1]) {
 1400                 if (pps_tf[1] > pps_tf[2]) {
 1401                         pps_offset = pps_tf[1];         /* 0 1 2 */
 1402                         v_usec = pps_tf[0] - pps_tf[2];
 1403                 } else if (pps_tf[2] > pps_tf[0]) {
 1404                         pps_offset = pps_tf[0];         /* 2 0 1 */
 1405                         v_usec = pps_tf[2] - pps_tf[1];
 1406                 } else {
 1407                         pps_offset = pps_tf[2];         /* 0 2 1 */
 1408                         v_usec = pps_tf[0] - pps_tf[1];
 1409                 }
 1410         } else {
 1411                 if (pps_tf[1] < pps_tf[2]) {
 1412                         pps_offset = pps_tf[1];         /* 2 1 0 */
 1413                         v_usec = pps_tf[2] - pps_tf[0];
 1414                 } else  if (pps_tf[2] < pps_tf[0]) {
 1415                         pps_offset = pps_tf[0];         /* 1 0 2 */
 1416                         v_usec = pps_tf[1] - pps_tf[2];
 1417                 } else {
 1418                         pps_offset = pps_tf[2];         /* 1 2 0 */
 1419                         v_usec = pps_tf[1] - pps_tf[0];
 1420                 }
 1421         }
 1422         if (v_usec > MAXTIME)
 1423                 pps_jitcnt++;
 1424         v_usec = (v_usec << PPS_AVG) - pps_jitter;
 1425         if (v_usec < 0)
 1426                 pps_jitter -= -v_usec >> PPS_AVG;
 1427         else
 1428                 pps_jitter += v_usec >> PPS_AVG;
 1429         if (pps_jitter > (MAXTIME >> 1))
 1430                 time_status |= STA_PPSJITTER;
 1431 
 1432         /*
 1433          * During the calibration interval adjust the starting time when
 1434          * the tick overflows. At the end of the interval compute the
 1435          * duration of the interval and the difference of the hardware
 1436          * counters at the beginning and end of the interval. This code
 1437          * is deliciously complicated by the fact valid differences may
 1438          * exceed the value of tick when using long calibration
 1439          * intervals and small ticks. Note that the counter can be
 1440          * greater than tick if caught at just the wrong instant, but
 1441          * the values returned and used here are correct.
 1442          */
 1443         bigtick = (long)tick << SHIFT_USEC;
 1444         pps_usec -= pps_freq;
 1445         if (pps_usec >= bigtick)
 1446                 pps_usec -= bigtick;
 1447         if (pps_usec < 0)
 1448                 pps_usec += bigtick;
 1449         pps_time.tv_sec++;
 1450         pps_count++;
 1451         if (pps_count < (1 << pps_shift))
 1452                 return;
 1453         pps_count = 0;
 1454         pps_calcnt++;
 1455         u_usec = usec << SHIFT_USEC;
 1456         v_usec = pps_usec - u_usec;
 1457         if (v_usec >= bigtick >> 1)
 1458                 v_usec -= bigtick;
 1459         if (v_usec < -(bigtick >> 1))
 1460                 v_usec += bigtick;
 1461         if (v_usec < 0)
 1462                 v_usec = -(-v_usec >> pps_shift);
 1463         else
 1464                 v_usec = v_usec >> pps_shift;
 1465         pps_usec = u_usec;
 1466         cal_sec = tvp->tv_sec;
 1467         cal_usec = tvp->tv_usec;
 1468         cal_sec -= pps_time.tv_sec;
 1469         cal_usec -= pps_time.tv_usec;
 1470         if (cal_usec < 0) {
 1471                 cal_usec += 1000000;
 1472                 cal_sec--;
 1473         }
 1474         pps_time = *tvp;
 1475 
 1476         /*
 1477          * Check for lost interrupts, noise, excessive jitter and
 1478          * excessive frequency error. The number of timer ticks during
 1479          * the interval may vary +-1 tick. Add to this a margin of one
 1480          * tick for the PPS signal jitter and maximum frequency
 1481          * deviation. If the limits are exceeded, the calibration
 1482          * interval is reset to the minimum and we start over.
 1483          */
 1484         u_usec = (long)tick << 1;
 1485         if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec))
 1486             || (cal_sec == 0 && cal_usec < u_usec))
 1487             || v_usec > time_tolerance || v_usec < -time_tolerance) {
 1488                 pps_errcnt++;
 1489                 pps_shift = PPS_SHIFT;
 1490                 pps_intcnt = 0;
 1491                 time_status |= STA_PPSERROR;
 1492                 return;
 1493         }
 1494 
 1495         /*
 1496          * A three-stage median filter is used to help deglitch the pps
 1497          * frequency. The median sample becomes the frequency offset
 1498          * estimate; the difference between the other two samples
 1499          * becomes the frequency dispersion (stability) estimate.
 1500          */
 1501         pps_ff[2] = pps_ff[1];
 1502         pps_ff[1] = pps_ff[0];
 1503         pps_ff[0] = v_usec;
 1504         if (pps_ff[0] > pps_ff[1]) {
 1505                 if (pps_ff[1] > pps_ff[2]) {
 1506                         u_usec = pps_ff[1];             /* 0 1 2 */
 1507                         v_usec = pps_ff[0] - pps_ff[2];
 1508                 } else if (pps_ff[2] > pps_ff[0]) {
 1509                         u_usec = pps_ff[0];             /* 2 0 1 */
 1510                         v_usec = pps_ff[2] - pps_ff[1];
 1511                 } else {
 1512                         u_usec = pps_ff[2];             /* 0 2 1 */
 1513                         v_usec = pps_ff[0] - pps_ff[1];
 1514                 }
 1515         } else {
 1516                 if (pps_ff[1] < pps_ff[2]) {
 1517                         u_usec = pps_ff[1];             /* 2 1 0 */
 1518                         v_usec = pps_ff[2] - pps_ff[0];
 1519                 } else  if (pps_ff[2] < pps_ff[0]) {
 1520                         u_usec = pps_ff[0];             /* 1 0 2 */
 1521                         v_usec = pps_ff[1] - pps_ff[2];
 1522                 } else {
 1523                         u_usec = pps_ff[2];             /* 1 2 0 */
 1524                         v_usec = pps_ff[1] - pps_ff[0];
 1525                 }
 1526         }
 1527 
 1528         /*
 1529          * Here the frequency dispersion (stability) is updated. If it
 1530          * is less than one-fourth the maximum (MAXFREQ), the frequency
 1531          * offset is updated as well, but clamped to the tolerance. It
 1532          * will be processed later by the hardclock() routine.
 1533          */
 1534         v_usec = (v_usec >> 1) - pps_stabil;
 1535         if (v_usec < 0)
 1536                 pps_stabil -= -v_usec >> PPS_AVG;
 1537         else
 1538                 pps_stabil += v_usec >> PPS_AVG;
 1539         if (pps_stabil > MAXFREQ >> 2) {
 1540                 pps_stbcnt++;
 1541                 time_status |= STA_PPSWANDER;
 1542                 return;
 1543         }
 1544         if (time_status & STA_PPSFREQ) {
 1545                 if (u_usec < 0) {
 1546                         pps_freq -= -u_usec >> PPS_AVG;
 1547                         if (pps_freq < -time_tolerance)
 1548                                 pps_freq = -time_tolerance;
 1549                         u_usec = -u_usec;
 1550                 } else {
 1551                         pps_freq += u_usec >> PPS_AVG;
 1552                         if (pps_freq > time_tolerance)
 1553                                 pps_freq = time_tolerance;
 1554                 }
 1555         }
 1556 
 1557         /*
 1558          * Here the calibration interval is adjusted. If the maximum
 1559          * time difference is greater than tick / 4, reduce the interval
 1560          * by half. If this is not the case for four consecutive
 1561          * intervals, double the interval.
 1562          */
 1563         if (u_usec << pps_shift > bigtick >> 2) {
 1564                 pps_intcnt = 0;
 1565                 if (pps_shift > PPS_SHIFT)
 1566                         pps_shift--;
 1567         } else if (pps_intcnt >= 4) {
 1568                 pps_intcnt = 0;
 1569                 if (pps_shift < PPS_SHIFTMAX)
 1570                         pps_shift++;
 1571         } else
 1572                 pps_intcnt++;
 1573 }
 1574 #endif /* PPS_SYNC */
 1575 #endif /* NTP  */
 1576 
 1577 /* timecounter compat functions */
 1578 void
 1579 nanotime(struct timespec *ts)
 1580 {
 1581         struct timeval tv;
 1582 
 1583         microtime(&tv);
 1584         TIMEVAL_TO_TIMESPEC(&tv, ts);
 1585 }
 1586 
 1587 void
 1588 getbinuptime(struct bintime *bt)
 1589 {
 1590         struct timeval tv;
 1591 
 1592         microtime(&tv);
 1593         timeval2bintime(&tv, bt);
 1594 }
 1595 
 1596 void
 1597 nanouptime(struct timespec *tsp)
 1598 {
 1599         int s;
 1600 
 1601         s = splclock();
 1602         TIMEVAL_TO_TIMESPEC(&mono_time, tsp);
 1603         splx(s);
 1604 }
 1605 
 1606 void
 1607 getnanouptime(struct timespec *tsp)
 1608 {
 1609         int s;
 1610 
 1611         s = splclock();
 1612         TIMEVAL_TO_TIMESPEC(&mono_time, tsp);
 1613         splx(s);
 1614 }
 1615 
 1616 void
 1617 getmicrouptime(struct timeval *tvp)
 1618 {
 1619         int s;
 1620 
 1621         s = splclock();
 1622         *tvp = mono_time;
 1623         splx(s);
 1624 }
 1625 
 1626 void
 1627 getnanotime(struct timespec *tsp)
 1628 {
 1629         int s;
 1630 
 1631         s = splclock();
 1632         TIMEVAL_TO_TIMESPEC(&time, tsp);
 1633         splx(s);
 1634 }
 1635 
 1636 void
 1637 getmicrotime(struct timeval *tvp)
 1638 {
 1639         int s;
 1640 
 1641         s = splclock();
 1642         *tvp = time;
 1643         splx(s);
 1644 }
 1645 #endif /* !__HAVE_TIMECOUNTER */

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