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freebsd-nq/sys/kern/kern_clock.c
Bruce Evans d841aaa740 Finished (?) cleaning up sysinit stuff.
1995-12-02 17:11:20 +00:00

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/*-
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
* $Id: kern_clock.c,v 1.19 1995/11/12 19:51:48 phk Exp $
*/
/* Portions of this software are covered by the following: */
/******************************************************************************
* *
* Copyright (c) David L. Mills 1993, 1994 *
* *
* Permission to use, copy, modify, and distribute this software and its *
* documentation for any purpose and without fee is hereby granted, provided *
* that the above copyright notice appears in all copies and that both the *
* copyright notice and this permission notice appear in supporting *
* documentation, and that the name University of Delaware not be used in *
* advertising or publicity pertaining to distribution of the software *
* without specific, written prior permission. The University of Delaware *
* makes no representations about the suitability this software for any *
* purpose. It is provided "as is" without express or implied warranty. *
* *
*****************************************************************************/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dkstat.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/timex.h>
#include <vm/vm.h>
#include <sys/sysctl.h>
#include <machine/cpu.h>
#include <machine/clock.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
static void initclocks __P((void *dummy));
SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
/* Does anybody else really care about these? */
struct callout *callfree, *callout, calltodo;
/* Some of these don't belong here, but it's easiest to concentrate them. */
long cp_time[CPUSTATES];
long dk_seek[DK_NDRIVE];
long dk_time[DK_NDRIVE];
long dk_wds[DK_NDRIVE];
long dk_wpms[DK_NDRIVE];
long dk_xfer[DK_NDRIVE];
int dk_busy;
int dk_ndrive = 0;
char dk_names[DK_NDRIVE][DK_NAMELEN];
long tk_cancc;
long tk_nin;
long tk_nout;
long tk_rawcc;
/*
* Clock handling routines.
*
* This code is written to operate with two timers that run independently of
* each other. The main clock, running hz times per second, is used to keep
* track of real time. The second timer handles kernel and user profiling,
* and does resource use estimation. If the second timer is programmable,
* it is randomized to avoid aliasing between the two clocks. For example,
* the randomization prevents an adversary from always giving up the cpu
* just before its quantum expires. Otherwise, it would never accumulate
* cpu ticks. The mean frequency of the second timer is stathz.
*
* If no second timer exists, stathz will be zero; in this case we drive
* profiling and statistics off the main clock. This WILL NOT be accurate;
* do not do it unless absolutely necessary.
*
* The statistics clock may (or may not) be run at a higher rate while
* profiling. This profile clock runs at profhz. We require that profhz
* be an integral multiple of stathz.
*
* If the statistics clock is running fast, it must be divided by the ratio
* profhz/stathz for statistics. (For profiling, every tick counts.)
*/
/*
* TODO:
* allocate more timeout table slots when table overflows.
*/
/*
* Bump a timeval by a small number of usec's.
*/
#define BUMPTIME(t, usec) { \
register volatile struct timeval *tp = (t); \
register long us; \
\
tp->tv_usec = us = tp->tv_usec + (usec); \
if (us >= 1000000) { \
tp->tv_usec = us - 1000000; \
tp->tv_sec++; \
} \
}
int stathz;
int profhz;
int profprocs;
int ticks;
static int psdiv, pscnt; /* prof => stat divider */
int psratio; /* ratio: prof / stat */
volatile struct timeval time;
volatile struct timeval mono_time;
/*
* Phase-lock loop (PLL) definitions
*
* The following variables are read and set by the ntp_adjtime() system
* call.
*
* time_state shows the state of the system clock, with values defined
* in the timex.h header file.
*
* time_status shows the status of the system clock, with bits defined
* in the timex.h header file.
*
* time_offset is used by the PLL to adjust the system time in small
* increments.
*
* time_constant determines the bandwidth or "stiffness" of the PLL.
*
* time_tolerance determines maximum frequency error or tolerance of the
* CPU clock oscillator and is a property of the architecture; however,
* in principle it could change as result of the presence of external
* discipline signals, for instance.
*
* time_precision is usually equal to the kernel tick variable; however,
* in cases where a precision clock counter or external clock is
* available, the resolution can be much less than this and depend on
* whether the external clock is working or not.
*
* time_maxerror is initialized by a ntp_adjtime() call and increased by
* the kernel once each second to reflect the maximum error
* bound growth.
*
* time_esterror is set and read by the ntp_adjtime() call, but
* otherwise not used by the kernel.
*/
int time_status = STA_UNSYNC; /* clock status bits */
int time_state = TIME_OK; /* clock state */
long time_offset = 0; /* time offset (us) */
long time_constant = 0; /* pll time constant */
long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */
long time_precision = 1; /* clock precision (us) */
long time_maxerror = MAXPHASE; /* maximum error (us) */
long time_esterror = MAXPHASE; /* estimated error (us) */
/*
* The following variables establish the state of the PLL and the
* residual time and frequency offset of the local clock. The scale
* factors are defined in the timex.h header file.
*
* time_phase and time_freq are the phase increment and the frequency
* increment, respectively, of the kernel time variable at each tick of
* the clock.
*
* time_freq is set via ntp_adjtime() from a value stored in a file when
* the synchronization daemon is first started. Its value is retrieved
* via ntp_adjtime() and written to the file about once per hour by the
* daemon.
*
* time_adj is the adjustment added to the value of tick at each timer
* interrupt and is recomputed at each timer interrupt.
*
* time_reftime is the second's portion of the system time on the last
* call to ntp_adjtime(). It is used to adjust the time_freq variable
* and to increase the time_maxerror as the time since last update
* increases.
*/
long time_phase = 0; /* phase offset (scaled us) */
long time_freq = 0; /* frequency offset (scaled ppm) */
long time_adj = 0; /* tick adjust (scaled 1 / hz) */
long time_reftime = 0; /* time at last adjustment (s) */
#ifdef PPS_SYNC
/*
* The following variables are used only if the if the kernel PPS
* discipline code is configured (PPS_SYNC). The scale factors are
* defined in the timex.h header file.
*
* pps_time contains the time at each calibration interval, as read by
* microtime().
*
* pps_offset is the time offset produced by the time median filter
* pps_tf[], while pps_jitter is the dispersion measured by this
* filter.
*
* pps_freq is the frequency offset produced by the frequency median
* filter pps_ff[], while pps_stabil is the dispersion measured by
* this filter.
*
* pps_usec is latched from a high resolution counter or external clock
* at pps_time. Here we want the hardware counter contents only, not the
* contents plus the time_tv.usec as usual.
*
* pps_valid counts the number of seconds since the last PPS update. It
* is used as a watchdog timer to disable the PPS discipline should the
* PPS signal be lost.
*
* pps_glitch counts the number of seconds since the beginning of an
* offset burst more than tick/2 from current nominal offset. It is used
* mainly to suppress error bursts due to priority conflicts between the
* PPS interrupt and timer interrupt.
*
* pps_count counts the seconds of the calibration interval, the
* duration of which is pps_shift in powers of two.
*
* pps_intcnt counts the calibration intervals for use in the interval-
* adaptation algorithm. It's just too complicated for words.
*/
struct timeval pps_time; /* kernel time at last interval */
long pps_offset = 0; /* pps time offset (us) */
long pps_jitter = MAXTIME; /* pps time dispersion (jitter) (us) */
long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */
long pps_freq = 0; /* frequency offset (scaled ppm) */
long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
long pps_ff[] = {0, 0, 0}; /* frequency offset median filter */
long pps_usec = 0; /* microsec counter at last interval */
long pps_valid = PPS_VALID; /* pps signal watchdog counter */
int pps_glitch = 0; /* pps signal glitch counter */
int pps_count = 0; /* calibration interval counter (s) */
int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
int pps_intcnt = 0; /* intervals at current duration */
/*
* PPS signal quality monitors
*
* pps_jitcnt counts the seconds that have been discarded because the
* jitter measured by the time median filter exceeds the limit MAXTIME
* (100 us).
*
* pps_calcnt counts the frequency calibration intervals, which are
* variable from 4 s to 256 s.
*
* pps_errcnt counts the calibration intervals which have been discarded
* because the wander exceeds the limit MAXFREQ (100 ppm) or where the
* calibration interval jitter exceeds two ticks.
*
* pps_stbcnt counts the calibration intervals that have been discarded
* because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
*/
long pps_jitcnt = 0; /* jitter limit exceeded */
long pps_calcnt = 0; /* calibration intervals */
long pps_errcnt = 0; /* calibration errors */
long pps_stbcnt = 0; /* stability limit exceeded */
#endif /* PPS_SYNC */
/* XXX none of this stuff works under FreeBSD */
#ifdef EXT_CLOCK
/*
* External clock definitions
*
* The following definitions and declarations are used only if an
* external clock (HIGHBALL or TPRO) is configured on the system.
*/
#define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */
/*
* The clock_count variable is set to CLOCK_INTERVAL at each PPS
* interrupt and decremented once each second.
*/
int clock_count = 0; /* CPU clock counter */
#ifdef HIGHBALL
/*
* The clock_offset and clock_cpu variables are used by the HIGHBALL
* interface. The clock_offset variable defines the offset between
* system time and the HIGBALL counters. The clock_cpu variable contains
* the offset between the system clock and the HIGHBALL clock for use in
* disciplining the kernel time variable.
*/
extern struct timeval clock_offset; /* Highball clock offset */
long clock_cpu = 0; /* CPU clock adjust */
#endif /* HIGHBALL */
#endif /* EXT_CLOCK */
/*
* hardupdate() - local clock update
*
* This routine is called by ntp_adjtime() to update the local clock
* phase and frequency. This is used to implement an adaptive-parameter,
* first-order, type-II phase-lock loop. The code computes new time and
* frequency offsets each time it is called. The hardclock() routine
* amortizes these offsets at each tick interrupt. If the kernel PPS
* discipline code is configured (PPS_SYNC), the PPS signal itself
* determines the new time offset, instead of the calling argument.
* Presumably, calls to ntp_adjtime() occur only when the caller
* believes the local clock is valid within some bound (+-128 ms with
* NTP). If the caller's time is far different than the PPS time, an
* argument will ensue, and it's not clear who will lose.
*
* For default SHIFT_UPDATE = 12, the offset is limited to +-512 ms, the
* maximum interval between updates is 4096 s and the maximum frequency
* offset is +-31.25 ms/s.
*
* Note: splclock() is in effect.
*/
void
hardupdate(offset)
long offset;
{
long ltemp, mtemp;
if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
return;
ltemp = offset;
#ifdef PPS_SYNC
if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
ltemp = pps_offset;
#endif /* PPS_SYNC */
if (ltemp > MAXPHASE)
time_offset = MAXPHASE << SHIFT_UPDATE;
else if (ltemp < -MAXPHASE)
time_offset = -(MAXPHASE << SHIFT_UPDATE);
else
time_offset = ltemp << SHIFT_UPDATE;
mtemp = time.tv_sec - time_reftime;
time_reftime = time.tv_sec;
if (mtemp > MAXSEC)
mtemp = 0;
/* ugly multiply should be replaced */
if (ltemp < 0)
time_freq -= (-ltemp * mtemp) >> (time_constant +
time_constant + SHIFT_KF - SHIFT_USEC);
else
time_freq += (ltemp * mtemp) >> (time_constant +
time_constant + SHIFT_KF - SHIFT_USEC);
if (time_freq > time_tolerance)
time_freq = time_tolerance;
else if (time_freq < -time_tolerance)
time_freq = -time_tolerance;
}
/*
* Initialize clock frequencies and start both clocks running.
*/
/* ARGSUSED*/
static void
initclocks(dummy)
void *dummy;
{
register int i;
/*
* Set divisors to 1 (normal case) and let the machine-specific
* code do its bit.
*/
psdiv = pscnt = 1;
cpu_initclocks();
/*
* Compute profhz/stathz, and fix profhz if needed.
*/
i = stathz ? stathz : hz;
if (profhz == 0)
profhz = i;
psratio = profhz / i;
}
/*
* The real-time timer, interrupting hz times per second.
*/
void
hardclock(frame)
register struct clockframe *frame;
{
register struct callout *p1;
register struct proc *p;
register int needsoft;
/*
* Update real-time timeout queue.
* At front of queue are some number of events which are ``due''.
* The time to these is <= 0 and if negative represents the
* number of ticks which have passed since it was supposed to happen.
* The rest of the q elements (times > 0) are events yet to happen,
* where the time for each is given as a delta from the previous.
* Decrementing just the first of these serves to decrement the time
* to all events.
*/
needsoft = 0;
for (p1 = calltodo.c_next; p1 != NULL; p1 = p1->c_next) {
if (--p1->c_time > 0)
break;
needsoft = 1;
if (p1->c_time == 0)
break;
}
p = curproc;
if (p) {
register struct pstats *pstats;
/*
* Run current process's virtual and profile time, as needed.
*/
pstats = p->p_stats;
if (CLKF_USERMODE(frame) &&
timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
psignal(p, SIGVTALRM);
if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
psignal(p, SIGPROF);
}
/*
* If no separate statistics clock is available, run it from here.
*/
if (stathz == 0)
statclock(frame);
/*
* Increment the time-of-day.
*/
ticks++;
{
int time_update;
struct timeval newtime = time;
long ltemp;
if (timedelta == 0) {
time_update = CPU_THISTICKLEN(tick);
} else {
time_update = CPU_THISTICKLEN(tick) + tickdelta;
timedelta -= tickdelta;
}
BUMPTIME(&mono_time, time_update);
/*
* Compute the phase adjustment. If the low-order bits
* (time_phase) of the update overflow, bump the high-order bits
* (time_update).
*/
time_phase += time_adj;
if (time_phase <= -FINEUSEC) {
ltemp = -time_phase >> SHIFT_SCALE;
time_phase += ltemp << SHIFT_SCALE;
time_update -= ltemp;
}
else if (time_phase >= FINEUSEC) {
ltemp = time_phase >> SHIFT_SCALE;
time_phase -= ltemp << SHIFT_SCALE;
time_update += ltemp;
}
newtime.tv_usec += time_update;
/*
* On rollover of the second the phase adjustment to be used for
* the next second is calculated. Also, the maximum error is
* increased by the tolerance. If the PPS frequency discipline
* code is present, the phase is increased to compensate for the
* CPU clock oscillator frequency error.
*
* With SHIFT_SCALE = 23, the maximum frequency adjustment is
* +-256 us per tick, or 25.6 ms/s at a clock frequency of 100
* Hz. The time contribution is shifted right a minimum of two
* bits, while the frequency contribution is a right shift.
* Thus, overflow is prevented if the frequency contribution is
* limited to half the maximum or 15.625 ms/s.
*/
if (newtime.tv_usec >= 1000000) {
newtime.tv_usec -= 1000000;
newtime.tv_sec++;
time_maxerror += time_tolerance >> SHIFT_USEC;
if (time_offset < 0) {
ltemp = -time_offset >>
(SHIFT_KG + time_constant);
time_offset += ltemp;
time_adj = -ltemp <<
(SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
} else {
ltemp = time_offset >>
(SHIFT_KG + time_constant);
time_offset -= ltemp;
time_adj = ltemp <<
(SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
}
#ifdef PPS_SYNC
/*
* Gnaw on the watchdog counter and update the frequency
* computed by the pll and the PPS signal.
*/
pps_valid++;
if (pps_valid == PPS_VALID) {
pps_jitter = MAXTIME;
pps_stabil = MAXFREQ;
time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
STA_PPSWANDER | STA_PPSERROR);
}
ltemp = time_freq + pps_freq;
#else
ltemp = time_freq;
#endif /* PPS_SYNC */
if (ltemp < 0)
time_adj -= -ltemp >>
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
else
time_adj += ltemp >>
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
/*
* When the CPU clock oscillator frequency is not a
* power of two in Hz, the SHIFT_HZ is only an
* approximate scale factor. In the SunOS kernel, this
* results in a PLL gain factor of 1/1.28 = 0.78 what it
* should be. In the following code the overall gain is
* increased by a factor of 1.25, which results in a
* residual error less than 3 percent.
*/
/* Same thing applies for FreeBSD --GAW */
if (hz == 100) {
if (time_adj < 0)
time_adj -= -time_adj >> 2;
else
time_adj += time_adj >> 2;
}
/* XXX - this is really bogus, but can't be fixed until
xntpd's idea of the system clock is fixed to know how
the user wants leap seconds handled; in the mean time,
we assume that users of NTP are running without proper
leap second support (this is now the default anyway) */
/*
* Leap second processing. If in leap-insert state at
* the end of the day, the system clock is set back one
* second; if in leap-delete state, the system clock is
* set ahead one second. The microtime() routine or
* external clock driver will insure that reported time
* is always monotonic. The ugly divides should be
* replaced.
*/
switch (time_state) {
case TIME_OK:
if (time_status & STA_INS)
time_state = TIME_INS;
else if (time_status & STA_DEL)
time_state = TIME_DEL;
break;
case TIME_INS:
if (newtime.tv_sec % 86400 == 0) {
newtime.tv_sec--;
time_state = TIME_OOP;
}
break;
case TIME_DEL:
if ((newtime.tv_sec + 1) % 86400 == 0) {
newtime.tv_sec++;
time_state = TIME_WAIT;
}
break;
case TIME_OOP:
time_state = TIME_WAIT;
break;
case TIME_WAIT:
if (!(time_status & (STA_INS | STA_DEL)))
time_state = TIME_OK;
}
}
CPU_CLOCKUPDATE(&time, &newtime);
}
/*
* Process callouts at a very low cpu priority, so we don't keep the
* relatively high clock interrupt priority any longer than necessary.
*/
if (needsoft) {
if (CLKF_BASEPRI(frame)) {
/*
* Save the overhead of a software interrupt;
* it will happen as soon as we return, so do it now.
*/
(void)splsoftclock();
softclock();
} else
setsoftclock();
}
}
/*
* Software (low priority) clock interrupt.
* Run periodic events from timeout queue.
*/
/*ARGSUSED*/
void
softclock()
{
register struct callout *c;
register void *arg;
register void (*func) __P((void *));
register int s;
s = splhigh();
while ((c = calltodo.c_next) != NULL && c->c_time <= 0) {
func = c->c_func;
arg = c->c_arg;
calltodo.c_next = c->c_next;
c->c_next = callfree;
callfree = c;
splx(s);
(*func)(arg);
(void) splhigh();
}
splx(s);
}
/*
* timeout --
* Execute a function after a specified length of time.
*
* untimeout --
* Cancel previous timeout function call.
*
* See AT&T BCI Driver Reference Manual for specification. This
* implementation differs from that one in that no identification
* value is returned from timeout, rather, the original arguments
* to timeout are used to identify entries for untimeout.
*/
void
timeout(ftn, arg, ticks)
timeout_t ftn;
void *arg;
register int ticks;
{
register struct callout *new, *p, *t;
register int s;
if (ticks <= 0)
ticks = 1;
/* Lock out the clock. */
s = splhigh();
/* Fill in the next free callout structure. */
if (callfree == NULL)
panic("timeout table full");
new = callfree;
callfree = new->c_next;
new->c_arg = arg;
new->c_func = ftn;
/*
* The time for each event is stored as a difference from the time
* of the previous event on the queue. Walk the queue, correcting
* the ticks argument for queue entries passed. Correct the ticks
* value for the queue entry immediately after the insertion point
* as well. Watch out for negative c_time values; these represent
* overdue events.
*/
for (p = &calltodo;
(t = p->c_next) != NULL && ticks > t->c_time; p = t)
if (t->c_time > 0)
ticks -= t->c_time;
new->c_time = ticks;
if (t != NULL)
t->c_time -= ticks;
/* Insert the new entry into the queue. */
p->c_next = new;
new->c_next = t;
splx(s);
}
void
untimeout(ftn, arg)
timeout_t ftn;
void *arg;
{
register struct callout *p, *t;
register int s;
s = splhigh();
for (p = &calltodo; (t = p->c_next) != NULL; p = t)
if (t->c_func == ftn && t->c_arg == arg) {
/* Increment next entry's tick count. */
if (t->c_next && t->c_time > 0)
t->c_next->c_time += t->c_time;
/* Move entry from callout queue to callfree queue. */
p->c_next = t->c_next;
t->c_next = callfree;
callfree = t;
break;
}
splx(s);
}
/*
* Compute number of hz until specified time. Used to
* compute third argument to timeout() from an absolute time.
*/
int
hzto(tv)
struct timeval *tv;
{
register unsigned long ticks;
register long sec, usec;
int s;
/*
* If the number of usecs in the whole seconds part of the time
* difference fits in a long, then the total number of usecs will
* fit in an unsigned long. Compute the total and convert it to
* ticks, rounding up and adding 1 to allow for the current tick
* to expire. Rounding also depends on unsigned long arithmetic
* to avoid overflow.
*
* Otherwise, if the number of ticks in the whole seconds part of
* the time difference fits in a long, then convert the parts to
* ticks separately and add, using similar rounding methods and
* overflow avoidance. This method would work in the previous
* case but it is slightly slower and assumes that hz is integral.
*
* Otherwise, round the time difference down to the maximum
* representable value.
*
* If ints have 32 bits, then the maximum value for any timeout in
* 10ms ticks is 248 days.
*/
s = splclock();
sec = tv->tv_sec - time.tv_sec;
usec = tv->tv_usec - time.tv_usec;
splx(s);
if (usec < 0) {
sec--;
usec += 1000000;
}
if (sec < 0) {
#ifdef DIAGNOSTIC
printf("hzto: negative time difference %ld sec %ld usec\n",
sec, usec);
#endif
ticks = 1;
} else if (sec <= LONG_MAX / 1000000)
ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
/ tick + 1;
else if (sec <= LONG_MAX / hz)
ticks = sec * hz
+ ((unsigned long)usec + (tick - 1)) / tick + 1;
else
ticks = LONG_MAX;
if (ticks > INT_MAX)
ticks = INT_MAX;
return (ticks);
}
/*
* Start profiling on a process.
*
* Kernel profiling passes proc0 which never exits and hence
* keeps the profile clock running constantly.
*/
void
startprofclock(p)
register struct proc *p;
{
int s;
if ((p->p_flag & P_PROFIL) == 0) {
p->p_flag |= P_PROFIL;
if (++profprocs == 1 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = psratio;
setstatclockrate(profhz);
splx(s);
}
}
}
/*
* Stop profiling on a process.
*/
void
stopprofclock(p)
register struct proc *p;
{
int s;
if (p->p_flag & P_PROFIL) {
p->p_flag &= ~P_PROFIL;
if (--profprocs == 0 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = 1;
setstatclockrate(stathz);
splx(s);
}
}
}
/*
* Statistics clock. Grab profile sample, and if divider reaches 0,
* do process and kernel statistics.
*/
void
statclock(frame)
register struct clockframe *frame;
{
#ifdef GPROF
register struct gmonparam *g;
#endif
register struct proc *p = curproc;
register int i;
if (p) {
struct pstats *pstats;
struct rusage *ru;
struct vmspace *vm;
/* bump the resource usage of integral space use */
if ((pstats = p->p_stats) && (ru = &pstats->p_ru) && (vm = p->p_vmspace)) {
ru->ru_ixrss += vm->vm_tsize * PAGE_SIZE / 1024;
ru->ru_idrss += vm->vm_dsize * PAGE_SIZE / 1024;
ru->ru_isrss += vm->vm_ssize * PAGE_SIZE / 1024;
if ((vm->vm_pmap.pm_stats.resident_count * PAGE_SIZE / 1024) >
ru->ru_maxrss) {
ru->ru_maxrss =
vm->vm_pmap.pm_stats.resident_count * PAGE_SIZE / 1024;
}
}
}
if (CLKF_USERMODE(frame)) {
if (p->p_flag & P_PROFIL)
addupc_intr(p, CLKF_PC(frame), 1);
if (--pscnt > 0)
return;
/*
* Came from user mode; CPU was in user state.
* If this process is being profiled record the tick.
*/
p->p_uticks++;
if (p->p_nice > NZERO)
cp_time[CP_NICE]++;
else
cp_time[CP_USER]++;
} else {
#ifdef GPROF
/*
* Kernel statistics are just like addupc_intr, only easier.
*/
g = &_gmonparam;
if (g->state == GMON_PROF_ON) {
i = CLKF_PC(frame) - g->lowpc;
if (i < g->textsize) {
i /= HISTFRACTION * sizeof(*g->kcount);
g->kcount[i]++;
}
}
#endif
if (--pscnt > 0)
return;
/*
* Came from kernel mode, so we were:
* - handling an interrupt,
* - doing syscall or trap work on behalf of the current
* user process, or
* - spinning in the idle loop.
* Whichever it is, charge the time as appropriate.
* Note that we charge interrupts to the current process,
* regardless of whether they are ``for'' that process,
* so that we know how much of its real time was spent
* in ``non-process'' (i.e., interrupt) work.
*/
if (CLKF_INTR(frame)) {
if (p != NULL)
p->p_iticks++;
cp_time[CP_INTR]++;
} else if (p != NULL) {
p->p_sticks++;
cp_time[CP_SYS]++;
} else
cp_time[CP_IDLE]++;
}
pscnt = psdiv;
/*
* We maintain statistics shown by user-level statistics
* programs: the amount of time in each cpu state, and
* the amount of time each of DK_NDRIVE ``drives'' is busy.
*
* XXX should either run linked list of drives, or (better)
* grab timestamps in the start & done code.
*/
for (i = 0; i < DK_NDRIVE; i++)
if (dk_busy & (1 << i))
dk_time[i]++;
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (p_estcpu) is increased here. The formula for computing
* priorities (in kern_synch.c) will compute a different value each
* time p_estcpu increases by 4. The cpu usage estimator ramps up
* quite quickly when the process is running (linearly), and decays
* away exponentially, at a rate which is proportionally slower when
* the system is busy. The basic principal is that the system will
* 90% forget that the process used a lot of CPU time in 5 * loadav
* seconds. This causes the system to favor processes which haven't
* run much recently, and to round-robin among other processes.
*/
if (p != NULL) {
p->p_cpticks++;
if (++p->p_estcpu == 0)
p->p_estcpu--;
if ((p->p_estcpu & 3) == 0) {
resetpriority(p);
if (p->p_priority >= PUSER)
p->p_priority = p->p_usrpri;
}
}
}
/*
* Return information about system clocks.
*/
static int
sysctl_kern_clockrate SYSCTL_HANDLER_ARGS
{
struct clockinfo clkinfo;
/*
* Construct clockinfo structure.
*/
clkinfo.hz = hz;
clkinfo.tick = tick;
clkinfo.profhz = profhz;
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
}
SYSCTL_OID(_kern, KERN_CLOCKRATE, clockrate,
CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0, sysctl_kern_clockrate, "");
/*#ifdef PPS_SYNC*/
#if 0
/* This code is completely bogus; if anybody ever wants to use it, get
* the current version from Dave Mills. */
/*
* hardpps() - discipline CPU clock oscillator to external pps signal
*
* This routine is called at each PPS interrupt in order to discipline
* the CPU clock oscillator to the PPS signal. It integrates successive
* phase differences between the two oscillators and calculates the
* frequency offset. This is used in hardclock() to discipline the CPU
* clock oscillator so that intrinsic frequency error is cancelled out.
* The code requires the caller to capture the time and hardware
* counter value at the designated PPS signal transition.
*/
void
hardpps(tvp, usec)
struct timeval *tvp; /* time at PPS */
long usec; /* hardware counter at PPS */
{
long u_usec, v_usec, bigtick;
long cal_sec, cal_usec;
/*
* During the calibration interval adjust the starting time when
* the tick overflows. At the end of the interval compute the
* duration of the interval and the difference of the hardware
* counters at the beginning and end of the interval. This code
* is deliciously complicated by the fact valid differences may
* exceed the value of tick when using long calibration
* intervals and small ticks. Note that the counter can be
* greater than tick if caught at just the wrong instant, but
* the values returned and used here are correct.
*/
bigtick = (long)tick << SHIFT_USEC;
pps_usec -= ntp_pll.ybar;
if (pps_usec >= bigtick)
pps_usec -= bigtick;
if (pps_usec < 0)
pps_usec += bigtick;
pps_time.tv_sec++;
pps_count++;
if (pps_count < (1 << pps_shift))
return;
pps_count = 0;
ntp_pll.calcnt++;
u_usec = usec << SHIFT_USEC;
v_usec = pps_usec - u_usec;
if (v_usec >= bigtick >> 1)
v_usec -= bigtick;
if (v_usec < -(bigtick >> 1))
v_usec += bigtick;
if (v_usec < 0)
v_usec = -(-v_usec >> ntp_pll.shift);
else
v_usec = v_usec >> ntp_pll.shift;
pps_usec = u_usec;
cal_sec = tvp->tv_sec;
cal_usec = tvp->tv_usec;
cal_sec -= pps_time.tv_sec;
cal_usec -= pps_time.tv_usec;
if (cal_usec < 0) {
cal_usec += 1000000;
cal_sec--;
}
pps_time = *tvp;
/*
* Check for lost interrupts, noise, excessive jitter and
* excessive frequency error. The number of timer ticks during
* the interval may vary +-1 tick. Add to this a margin of one
* tick for the PPS signal jitter and maximum frequency
* deviation. If the limits are exceeded, the calibration
* interval is reset to the minimum and we start over.
*/
u_usec = (long)tick << 1;
if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec))
|| (cal_sec == 0 && cal_usec < u_usec))
|| v_usec > ntp_pll.tolerance || v_usec < -ntp_pll.tolerance) {
ntp_pll.jitcnt++;
ntp_pll.shift = NTP_PLL.SHIFT;
pps_dispinc = PPS_DISPINC;
ntp_pll.intcnt = 0;
return;
}
/*
* A three-stage median filter is used to help deglitch the pps
* signal. The median sample becomes the offset estimate; the
* difference between the other two samples becomes the
* dispersion estimate.
*/
pps_mf[2] = pps_mf[1];
pps_mf[1] = pps_mf[0];
pps_mf[0] = v_usec;
if (pps_mf[0] > pps_mf[1]) {
if (pps_mf[1] > pps_mf[2]) {
u_usec = pps_mf[1]; /* 0 1 2 */
v_usec = pps_mf[0] - pps_mf[2];
} else if (pps_mf[2] > pps_mf[0]) {
u_usec = pps_mf[0]; /* 2 0 1 */
v_usec = pps_mf[2] - pps_mf[1];
} else {
u_usec = pps_mf[2]; /* 0 2 1 */
v_usec = pps_mf[0] - pps_mf[1];
}
} else {
if (pps_mf[1] < pps_mf[2]) {
u_usec = pps_mf[1]; /* 2 1 0 */
v_usec = pps_mf[2] - pps_mf[0];
} else if (pps_mf[2] < pps_mf[0]) {
u_usec = pps_mf[0]; /* 1 0 2 */
v_usec = pps_mf[1] - pps_mf[2];
} else {
u_usec = pps_mf[2]; /* 1 2 0 */
v_usec = pps_mf[1] - pps_mf[0];
}
}
/*
* Here the dispersion average is updated. If it is less than
* the threshold pps_dispmax, the frequency average is updated
* as well, but clamped to the tolerance.
*/
v_usec = (v_usec >> 1) - ntp_pll.disp;
if (v_usec < 0)
ntp_pll.disp -= -v_usec >> PPS_AVG;
else
ntp_pll.disp += v_usec >> PPS_AVG;
if (ntp_pll.disp > pps_dispmax) {
ntp_pll.discnt++;
return;
}
if (u_usec < 0) {
ntp_pll.ybar -= -u_usec >> PPS_AVG;
if (ntp_pll.ybar < -ntp_pll.tolerance)
ntp_pll.ybar = -ntp_pll.tolerance;
u_usec = -u_usec;
} else {
ntp_pll.ybar += u_usec >> PPS_AVG;
if (ntp_pll.ybar > ntp_pll.tolerance)
ntp_pll.ybar = ntp_pll.tolerance;
}
/*
* Here the calibration interval is adjusted. If the maximum
* time difference is greater than tick/4, reduce the interval
* by half. If this is not the case for four consecutive
* intervals, double the interval.
*/
if (u_usec << ntp_pll.shift > bigtick >> 2) {
ntp_pll.intcnt = 0;
if (ntp_pll.shift > NTP_PLL.SHIFT) {
ntp_pll.shift--;
pps_dispinc <<= 1;
}
} else if (ntp_pll.intcnt >= 4) {
ntp_pll.intcnt = 0;
if (ntp_pll.shift < NTP_PLL.SHIFTMAX) {
ntp_pll.shift++;
pps_dispinc >>= 1;
}
} else
ntp_pll.intcnt++;
}
#endif /* PPS_SYNC */
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