Redo Kernel NTP PLL support, kernel side.

This code is mostly taken from the 1.1 port (which was in turn taken from
Dave Mills's kern.tar.Z example).  A few significant differences:

1) ntp_gettime() is now a MIB variable rather than a system call.  A few
fiddles are done in libc to make it behave the same.

2) mono_time does not participate in the PLL adjustments.

3) A new interface has been defined (in <machine/clock.h>) for doing
possibly machine-dependent things around the time of the clock update.
This is used in Pentium kernels to disable interrupts, set `time', and
reset the CPU cycle counter as quickly as possible to avoid jitter in
microtime().  Measurements show an apparent resolution of a bit more than
8.14usec, which is reasonable given system-call overhead.
This commit is contained in:
Garrett Wollman 1994-09-18 20:40:01 +00:00
parent 69f5174d9a
commit 3f31c649d1
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=2858
20 changed files with 2129 additions and 154 deletions

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@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
* $Id: clock.c,v 1.16 1994/08/18 22:34:50 wollman Exp $
* $Id: clock.c,v 1.17 1994/09/14 23:09:06 ache Exp $
*/
/*
@ -79,27 +79,6 @@ void
clkintr(frame)
struct clockframe frame;
{
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
if(pentium_mhz) {
__asm __volatile("movl $0x10,%%ecx\n"
"xorl %%eax,%%eax\n"
"movl %%eax,%%edx\n"
".byte 0x0f, 0x30\n"
"#%0%1"
: "=m"(frame) /* no outputs */
: "b"(&frame) /* fake input */
: "ax", "cx", "dx");
}
#endif
hardclock(&frame);
}

49
sys/amd64/include/clock.h Normal file
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@ -0,0 +1,49 @@
/*
* Kernel interface to machine-dependent clock driver.
* Garrett Wollman, September 1994.
* This file is in the public domain.
*/
#ifndef _MACHINE_CLOCK_H_
#define _MACHINE_CLOCK_H_ 1
extern int pentium_mhz;
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
#define CPU_CLOCKUPDATE(otime, ntime) \
do { \
if(pentium_mhz) { \
__asm __volatile("cli\n" \
"movl (%2),%%eax\n" \
"movl %%eax,(%1)\n" \
"movl 4(%2),%%eax\n" \
"movl %%eax,4(%1)\n" \
"movl $0x10,%%ecx\n" \
"xorl %%eax,%%eax\n" \
"movl %%eax,%%edx\n" \
".byte 0x0f, 0x30\n" \
"sti\n" \
"#%0%1%2" \
: "=m"(*otime) /* no outputs */ \
: "c"(otime), "b"(ntime) /* fake input */ \
: "ax", "cx", "dx"); \
} else { \
*(otime) = *(ntime); \
} \
} while(0)
#else
#define CPU_CLOCKUPDATE(otime, ntime) \
(*(otime) = *(ntime))
#endif
#endif /* _MACHINE_CLOCK_H_ */

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@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
* $Id: clock.c,v 1.16 1994/08/18 22:34:50 wollman Exp $
* $Id: clock.c,v 1.17 1994/09/14 23:09:06 ache Exp $
*/
/*
@ -79,27 +79,6 @@ void
clkintr(frame)
struct clockframe frame;
{
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
if(pentium_mhz) {
__asm __volatile("movl $0x10,%%ecx\n"
"xorl %%eax,%%eax\n"
"movl %%eax,%%edx\n"
".byte 0x0f, 0x30\n"
"#%0%1"
: "=m"(frame) /* no outputs */
: "b"(&frame) /* fake input */
: "ax", "cx", "dx");
}
#endif
hardclock(&frame);
}

View File

@ -49,6 +49,7 @@ kern/kern_ktrace.c standard
kern/kern_lockf.c standard
kern/kern_lkm.c optional lkm
kern/kern_malloc.c standard
kern/kern_ntptime.c standard
kern/kern_physio.c standard
kern/kern_proc.c standard
kern/kern_prot.c standard

View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
* $Id: clock.c,v 1.16 1994/08/18 22:34:50 wollman Exp $
* $Id: clock.c,v 1.17 1994/09/14 23:09:06 ache Exp $
*/
/*
@ -79,27 +79,6 @@ void
clkintr(frame)
struct clockframe frame;
{
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
if(pentium_mhz) {
__asm __volatile("movl $0x10,%%ecx\n"
"xorl %%eax,%%eax\n"
"movl %%eax,%%edx\n"
".byte 0x0f, 0x30\n"
"#%0%1"
: "=m"(frame) /* no outputs */
: "b"(&frame) /* fake input */
: "ax", "cx", "dx");
}
#endif
hardclock(&frame);
}

49
sys/i386/include/clock.h Normal file
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@ -0,0 +1,49 @@
/*
* Kernel interface to machine-dependent clock driver.
* Garrett Wollman, September 1994.
* This file is in the public domain.
*/
#ifndef _MACHINE_CLOCK_H_
#define _MACHINE_CLOCK_H_ 1
extern int pentium_mhz;
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
#define CPU_CLOCKUPDATE(otime, ntime) \
do { \
if(pentium_mhz) { \
__asm __volatile("cli\n" \
"movl (%2),%%eax\n" \
"movl %%eax,(%1)\n" \
"movl 4(%2),%%eax\n" \
"movl %%eax,4(%1)\n" \
"movl $0x10,%%ecx\n" \
"xorl %%eax,%%eax\n" \
"movl %%eax,%%edx\n" \
".byte 0x0f, 0x30\n" \
"sti\n" \
"#%0%1%2" \
: "=m"(*otime) /* no outputs */ \
: "c"(otime), "b"(ntime) /* fake input */ \
: "ax", "cx", "dx"); \
} else { \
*(otime) = *(ntime); \
} \
} while(0)
#else
#define CPU_CLOCKUPDATE(otime, ntime) \
(*(otime) = *(ntime))
#endif
#endif /* _MACHINE_CLOCK_H_ */

View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
* $Id: clock.c,v 1.16 1994/08/18 22:34:50 wollman Exp $
* $Id: clock.c,v 1.17 1994/09/14 23:09:06 ache Exp $
*/
/*
@ -79,27 +79,6 @@ void
clkintr(frame)
struct clockframe frame;
{
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
if(pentium_mhz) {
__asm __volatile("movl $0x10,%%ecx\n"
"xorl %%eax,%%eax\n"
"movl %%eax,%%edx\n"
".byte 0x0f, 0x30\n"
"#%0%1"
: "=m"(frame) /* no outputs */
: "b"(&frame) /* fake input */
: "ax", "cx", "dx");
}
#endif
hardclock(&frame);
}

View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* from: @(#)clock.c 7.2 (Berkeley) 5/12/91
* $Id: clock.c,v 1.16 1994/08/18 22:34:50 wollman Exp $
* $Id: clock.c,v 1.17 1994/09/14 23:09:06 ache Exp $
*/
/*
@ -79,27 +79,6 @@ void
clkintr(frame)
struct clockframe frame;
{
#ifdef I586_CPU
/*
* This resets the CPU cycle counter to zero, to make our
* job easier in microtime(). Some fancy ifdefs could speed
* this up for Pentium-only kernels.
* We want this to be done as close as possible to the actual
* timer incrementing in hardclock(), because there is a window
* between the two where the value is no longer valid. Experimentation
* may reveal a good precompensation to apply in microtime().
*/
if(pentium_mhz) {
__asm __volatile("movl $0x10,%%ecx\n"
"xorl %%eax,%%eax\n"
"movl %%eax,%%edx\n"
".byte 0x0f, 0x30\n"
"#%0%1"
: "=m"(frame) /* no outputs */
: "b"(&frame) /* fake input */
: "ax", "cx", "dx");
}
#endif
hardclock(&frame);
}

View File

@ -2,7 +2,7 @@
* System call switch table.
*
* DO NOT EDIT-- this file is automatically generated.
* created from $Id: syscalls.master,v 1.7 1994/09/13 00:48:19 wollman Exp $
* created from $Id: syscalls.master,v 1.8 1994/09/13 14:46:54 dfr Exp $
*/
#include <sys/param.h>
@ -473,7 +473,7 @@ struct sysent sysent[] = {
{ 0, nosys }, /* 172 = nosys */
{ 0, nosys }, /* 173 = nosys */
{ 0, nosys }, /* 174 = nosys */
{ 1, nosys }, /* 175 = ntp_gettime */
{ 0, nosys }, /* 175 = nosys */
{ 1, nosys }, /* 176 = ntp_adjtime */
{ 0, nosys }, /* 177 = nosys */
{ 0, nosys }, /* 178 = nosys */

View File

@ -36,9 +36,26 @@
* SUCH DAMAGE.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
* $Id: kern_clock.c,v 1.4 1994/08/18 22:34:58 wollman Exp $
* $Id: kern_clock.c,v 1.5 1994/08/27 16:14:26 davidg 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>
@ -46,9 +63,11 @@
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/timex.h>
#include <vm/vm.h>
#include <machine/cpu.h>
#include <machine/clock.h>
#ifdef GPROF
#include <sys/gmon.h>
@ -127,6 +146,238 @@ 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.
*/
@ -207,18 +458,164 @@ hardclock(frame)
statclock(frame);
/*
* Increment the time-of-day. The increment is just ``tick'' unless
* we are still adjusting the clock; see adjtime().
* Increment the time-of-day.
*/
ticks++;
if (timedelta == 0)
delta = tick;
else {
delta = tick + tickdelta;
timedelta -= tickdelta;
{
int time_update;
struct timeval newtime = time;
long ltemp;
if (timedelta == 0) {
time_update = tick;
} else {
if (timedelta < 0) {
time_update = tick - tickdelta;
timedelta += tickdelta;
} else {
time_update = 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);
}
BUMPTIME(&time, delta);
BUMPTIME(&mono_time, delta);
/*
* Process callouts at a very low cpu priority, so we don't keep the
@ -563,3 +960,171 @@ sysctl_clockrate(where, sizep)
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo)));
}
/*#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 */

269
sys/kern/kern_ntptime.c Normal file
View File

@ -0,0 +1,269 @@
/******************************************************************************
* *
* 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. *
* *
******************************************************************************/
/*
* Modification history kern_ntptime.c
*
* 24 Mar 94 David L. Mills
* Revised syscall interface to include new variables for PPS
* time discipline.
*
* 14 Feb 94 David L. Mills
* Added code for external clock
*
* 28 Nov 93 David L. Mills
* Revised frequency scaling to conform with adjusted parameters
*
* 17 Sep 93 David L. Mills
* Created file
*/
/*
* ntp_gettime(), ntp_adjtime() - precision time interface for SunOS
* 4.1.1 and 4.1.3
*
* These routines consitute the Network Time Protocol (NTP) interfaces
* for user and daemon application programs. The ntp_gettime() routine
* provides the time, maximum error (synch distance) and estimated error
* (dispersion) to client user application programs. The ntp_adjtime()
* routine is used by the NTP daemon to adjust the system clock to an
* externally derived time. The time offset and related variables set by
* this routine are used by hardclock() to adjust the phase and
* frequency of the phase-lock loop which controls the system clock.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/timex.h>
#include <sys/sysctl.h>
/*
* The following variables are used by the hardclock() routine in the
* kern_clock.c module and are described in that module.
*/
extern struct timeval time; /* kernel time variable */
extern int time_state; /* clock state */
extern int time_status; /* clock status bits */
extern long time_offset; /* time adjustment (us) */
extern long time_freq; /* frequency offset (scaled ppm) */
extern long time_maxerror; /* maximum error (us) */
extern long time_esterror; /* estimated error (us) */
extern long time_constant; /* pll time constant */
extern long time_precision; /* clock precision (us) */
extern long time_tolerance; /* frequency tolerance (scaled ppm) */
#ifdef PPS_SYNC
/*
* The following variables are used only if the PPS signal discipline
* is configured in the kernel.
*/
extern int pps_shift; /* interval duration (s) (shift) */
extern long pps_freq; /* pps frequency offset (scaled ppm) */
extern long pps_jitter; /* pps jitter (us) */
extern long pps_stabil; /* pps stability (scaled ppm) */
extern long pps_jitcnt; /* jitter limit exceeded */
extern long pps_calcnt; /* calibration intervals */
extern long pps_errcnt; /* calibration errors */
extern long pps_stbcnt; /* stability limit exceeded */
#endif /* PPS_SYNC */
int
ntp_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
void *newp, size_t newlen, struct proc *p)
{
struct timeval atv;
struct ntptimeval ntv;
int s;
/* All names at this level are terminal. */
if (namelen != 1) {
return ENOTDIR;
}
if (name[0] != NTP_PLL_GETTIME) {
return EOPNOTSUPP;
}
s = splclock();
#ifdef EXT_CLOCK
/*
* The microtime() external clock routine returns a
* status code. If less than zero, we declare an error
* in the clock status word and return the kernel
* (software) time variable. While there are other
* places that call microtime(), this is the only place
* that matters from an application point of view.
*/
if (microtime(&atv) < 0) {
time_status |= STA_CLOCKERR;
ntv.time = time;
} else {
time_status &= ~STA_CLOCKERR;
}
#else /* EXT_CLOCK */
microtime(&atv);
#endif /* EXT_CLOCK */
ntv.time = atv;
ntv.maxerror = time_maxerror;
ntv.esterror = time_esterror;
splx(s);
ntv.time_state = time_state;
/*
* Status word error decode. If any of these conditions
* occur, an error is returned, instead of the status
* word. Most applications will care only about the fact
* the system clock may not be trusted, not about the
* details.
*
* Hardware or software error
*/
if (time_status & (STA_UNSYNC | STA_CLOCKERR)) {
ntv.time_state = TIME_ERROR;
}
/*
* PPS signal lost when either time or frequency
* synchronization requested
*/
if (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
!(time_status & STA_PPSSIGNAL)) {
ntv.time_state = TIME_ERROR;
}
/*
* PPS jitter exceeded when time synchronization
* requested
*/
if (time_status & STA_PPSTIME &&
time_status & STA_PPSJITTER) {
ntv.time_state = TIME_ERROR;
}
/*
* PPS wander exceeded or calibration error when
* frequency synchronization requested
*/
if (time_status & STA_PPSFREQ &&
time_status & (STA_PPSWANDER | STA_PPSERROR)) {
ntv.time_state = TIME_ERROR;
}
return(sysctl_rdstruct(oldp, oldlenp, newp, &ntv, sizeof ntv));
}
/*
* ntp_adjtime() - NTP daemon application interface
*/
struct ntp_adjtime_args {
struct timex *tp;
};
int
ntp_adjtime(struct proc *p, struct ntp_adjtime_args *uap, int *retval)
{
struct timex ntv;
int modes;
int s;
int error;
error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv));
if (error)
return error;
/*
* Update selected clock variables - only the superuser can
* change anything. Note that there is no error checking here on
* the assumption the superuser should know what it is doing.
*/
modes = ntv.modes;
if ((modes != 0)
&& (error = suser(p->p_cred->pc_ucred, &p->p_acflag)))
return error;
s = splclock();
if (modes & MOD_FREQUENCY)
#ifdef PPS_SYNC
time_freq = ntv.freq - pps_freq;
#else /* PPS_SYNC */
time_freq = ntv.freq;
#endif /* PPS_SYNC */
if (modes & MOD_MAXERROR)
time_maxerror = ntv.maxerror;
if (modes & MOD_ESTERROR)
time_esterror = ntv.esterror;
if (modes & MOD_STATUS) {
time_status &= STA_RONLY;
time_status |= ntv.status & ~STA_RONLY;
}
if (modes & MOD_TIMECONST)
time_constant = ntv.constant;
if (modes & MOD_OFFSET)
hardupdate(ntv.offset);
/*
* Retrieve all clock variables
*/
if (time_offset < 0)
ntv.offset = -(-time_offset >> SHIFT_UPDATE);
else
ntv.offset = time_offset >> SHIFT_UPDATE;
#ifdef PPS_SYNC
ntv.freq = time_freq + pps_freq;
#else /* PPS_SYNC */
ntv.freq = time_freq;
#endif /* PPS_SYNC */
ntv.maxerror = time_maxerror;
ntv.esterror = time_esterror;
ntv.status = time_status;
ntv.constant = time_constant;
ntv.precision = time_precision;
ntv.tolerance = time_tolerance;
#ifdef PPS_SYNC
ntv.shift = pps_shift;
ntv.ppsfreq = pps_freq;
ntv.jitter = pps_jitter >> PPS_AVG;
ntv.stabil = pps_stabil;
ntv.calcnt = pps_calcnt;
ntv.errcnt = pps_errcnt;
ntv.jitcnt = pps_jitcnt;
ntv.stbcnt = pps_stbcnt;
#endif /* PPS_SYNC */
(void)splx(s);
error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv));
if (!error) {
/*
* Status word error decode. See comments in
* ntp_gettime() routine.
*/
retval[0] = time_state;
if (time_status & (STA_UNSYNC | STA_CLOCKERR))
retval[0] = TIME_ERROR;
if (time_status & (STA_PPSFREQ | STA_PPSTIME) &&
!(time_status & STA_PPSSIGNAL))
retval[0] = TIME_ERROR;
if (time_status & STA_PPSTIME &&
time_status & STA_PPSJITTER)
retval[0] = TIME_ERROR;
if (time_status & STA_PPSFREQ &&
time_status & (STA_PPSWANDER | STA_PPSERROR))
retval[0] = TIME_ERROR;
}
return error;
}

View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* @(#)kern_sysctl.c 8.4 (Berkeley) 4/14/94
* $Id: kern_sysctl.c,v 1.10 1994/09/14 23:21:00 ache Exp $
* $Id: kern_sysctl.c,v 1.11 1994/09/16 00:53:58 ache Exp $
*/
/*
@ -64,6 +64,7 @@ extern sysctlfn vm_sysctl;
extern sysctlfn fs_sysctl;
extern sysctlfn net_sysctl;
extern sysctlfn cpu_sysctl;
extern sysctlfn ntp_sysctl;
/*
* Locking and stats
@ -201,7 +202,8 @@ kern_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
extern char ostype[], osrelease[];
/* all sysctl names at this level are terminal */
if (namelen != 1 && !(name[0] == KERN_PROC || name[0] == KERN_PROF))
if (namelen != 1 && !(name[0] == KERN_PROC || name[0] == KERN_PROF
|| name[0] == KERN_NTP_PLL))
return (ENOTDIR); /* overloaded */
switch (name[0]) {
@ -289,6 +291,9 @@ kern_sysctl(name, namelen, oldp, oldlenp, newp, newlen, p)
#else
return (sysctl_rdint(oldp, oldlenp, newp, 0));
#endif
case KERN_NTP_PLL:
return (ntp_sysctl(name + 1, namelen - 1, oldp, oldlenp,
newp, newlen, p));
default:
return (EOPNOTSUPP);
}

View File

@ -36,9 +36,26 @@
* SUCH DAMAGE.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
* $Id: kern_clock.c,v 1.4 1994/08/18 22:34:58 wollman Exp $
* $Id: kern_clock.c,v 1.5 1994/08/27 16:14:26 davidg 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>
@ -46,9 +63,11 @@
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/timex.h>
#include <vm/vm.h>
#include <machine/cpu.h>
#include <machine/clock.h>
#ifdef GPROF
#include <sys/gmon.h>
@ -127,6 +146,238 @@ 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.
*/
@ -207,18 +458,164 @@ hardclock(frame)
statclock(frame);
/*
* Increment the time-of-day. The increment is just ``tick'' unless
* we are still adjusting the clock; see adjtime().
* Increment the time-of-day.
*/
ticks++;
if (timedelta == 0)
delta = tick;
else {
delta = tick + tickdelta;
timedelta -= tickdelta;
{
int time_update;
struct timeval newtime = time;
long ltemp;
if (timedelta == 0) {
time_update = tick;
} else {
if (timedelta < 0) {
time_update = tick - tickdelta;
timedelta += tickdelta;
} else {
time_update = 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);
}
BUMPTIME(&time, delta);
BUMPTIME(&mono_time, delta);
/*
* Process callouts at a very low cpu priority, so we don't keep the
@ -563,3 +960,171 @@ sysctl_clockrate(where, sizep)
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo)));
}
/*#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 */

View File

@ -36,9 +36,26 @@
* SUCH DAMAGE.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
* $Id: kern_clock.c,v 1.4 1994/08/18 22:34:58 wollman Exp $
* $Id: kern_clock.c,v 1.5 1994/08/27 16:14:26 davidg 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>
@ -46,9 +63,11 @@
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/timex.h>
#include <vm/vm.h>
#include <machine/cpu.h>
#include <machine/clock.h>
#ifdef GPROF
#include <sys/gmon.h>
@ -127,6 +146,238 @@ 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.
*/
@ -207,18 +458,164 @@ hardclock(frame)
statclock(frame);
/*
* Increment the time-of-day. The increment is just ``tick'' unless
* we are still adjusting the clock; see adjtime().
* Increment the time-of-day.
*/
ticks++;
if (timedelta == 0)
delta = tick;
else {
delta = tick + tickdelta;
timedelta -= tickdelta;
{
int time_update;
struct timeval newtime = time;
long ltemp;
if (timedelta == 0) {
time_update = tick;
} else {
if (timedelta < 0) {
time_update = tick - tickdelta;
timedelta += tickdelta;
} else {
time_update = 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);
}
BUMPTIME(&time, delta);
BUMPTIME(&mono_time, delta);
/*
* Process callouts at a very low cpu priority, so we don't keep the
@ -563,3 +960,171 @@ sysctl_clockrate(where, sizep)
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo)));
}
/*#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 */

View File

@ -2,7 +2,7 @@
* System call names.
*
* DO NOT EDIT-- this file is automatically generated.
* created from $Id: syscalls.master,v 1.7 1994/09/13 00:48:19 wollman Exp $
* created from $Id: syscalls.master,v 1.8 1994/09/13 14:46:54 dfr Exp $
*/
char *syscallnames[] = {
@ -213,7 +213,7 @@ char *syscallnames[] = {
"#172", /* 172 = nosys */
"#173", /* 173 = nosys */
"#174", /* 174 = nosys */
"ntp_gettime", /* 175 = ntp_gettime */
"#175", /* 175 = nosys */
"ntp_adjtime", /* 176 = ntp_adjtime */
"#177", /* 177 = nosys */
"#178", /* 178 = nosys */

View File

@ -1,4 +1,4 @@
$Id: syscalls.master,v 1.7 1994/09/13 00:48:19 wollman Exp $
$Id: syscalls.master,v 1.8 1994/09/13 14:46:54 dfr Exp $
; from: @(#)syscalls.master 8.2 (Berkeley) 1/13/94
;
; System call name/number master file.
@ -240,7 +240,7 @@
172 UNIMPL 0 NOHIDE nosys
173 UNIMPL 0 NOHIDE nosys
174 UNIMPL 0 NOHIDE nosys
175 STD 1 BSD nosys ntp_gettime
175 UNIMPL 0 NOHIDE nosys
176 STD 1 BSD nosys ntp_adjtime
177 UNIMPL 0 NOHIDE nosys
178 UNIMPL 0 NOHIDE nosys

View File

@ -2,7 +2,7 @@
* System call hiders.
*
* DO NOT EDIT-- this file is automatically generated.
* created from $Id: syscalls.master,v 1.7 1994/09/13 00:48:19 wollman Exp $
* created from $Id: syscalls.master,v 1.8 1994/09/13 14:46:54 dfr Exp $
*/
HIDE_POSIX(fork)
@ -189,7 +189,6 @@ HIDE_BSD(shmsys)
HIDE_BSD(nosys)
#endif
HIDE_BSD(nosys)
HIDE_BSD(nosys)
HIDE_POSIX(setgid)
HIDE_BSD(setegid)
HIDE_BSD(seteuid)

View File

@ -2,7 +2,7 @@
* System call numbers.
*
* DO NOT EDIT-- this file is automatically generated.
* created from $Id: syscalls.master,v 1.7 1994/09/13 00:48:19 wollman Exp $
* created from $Id: syscalls.master,v 1.8 1994/09/13 14:46:54 dfr Exp $
*/
#define SYS_syscall 0
@ -168,7 +168,6 @@
#define SYS_semsys 169
#define SYS_msgsys 170
#define SYS_shmsys 171
#define SYS_ntp_gettime 175
#define SYS_ntp_adjtime 176
#define SYS_setgid 181
#define SYS_setegid 182

View File

@ -34,7 +34,7 @@
* SUCH DAMAGE.
*
* @(#)sysctl.h 8.1 (Berkeley) 6/2/93
* $Id: sysctl.h,v 1.8 1994/09/16 00:50:02 ache Exp $
* $Id: sysctl.h,v 1.9 1994/09/16 01:09:42 ache Exp $
*/
#ifndef _SYS_SYSCTL_H_
@ -131,7 +131,8 @@ struct ctlname {
#define KERN_DOMAINNAME 22 /* string: YP domain name */
#define KERN_UPDATEINTERVAL 23 /* int: update process sleep time */
#define KERN_OSRELDATE 24 /* int: OS release date */
#define KERN_MAXID 25 /* number of valid kern ids */
#define KERN_NTP_PLL 25 /* node: NTP PLL control */
#define KERN_MAXID 26 /* number of valid kern ids */
#define CTL_KERN_NAMES { \
{ 0, 0 }, \
@ -159,6 +160,7 @@ struct ctlname {
{ "domainname", CTLTYPE_STRING }, \
{ "update", CTLTYPE_INT }, \
{ "osreldate", CTLTYPE_INT }, \
{ "ntp_pll", CTLTYPE_NODE }, \
}
/*

View File

@ -242,6 +242,7 @@ struct ntptimeval {
struct timeval time; /* current time (ro) */
long maxerror; /* maximum error (us) (ro) */
long esterror; /* estimated error (us) (ro) */
int time_state; /* what ntp_gettime returns */
};
/*
@ -276,6 +277,17 @@ struct timex {
};
#ifdef __FreeBSD__
/*
* sysctl identifiers underneath kern.ntp_pll
*/
#define NTP_PLL_GETTIME 1 /* used by ntp_gettime() */
#define NTP_PLL_MAXID 2 /* number of valid ids */
#define NTP_PLL_NAMES { \
{ 0, 0 }, \
{ "gettime", CTLTYPE_STRUCT }, \
}
#ifndef KERNEL
#include <sys/cdefs.h>