freebsd-dev/sys/kern/kern_tc.c

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/*-
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
*
* Copyright (c) 2011 The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed by Julien Ridoux at the University
* of Melbourne under sponsorship from the FreeBSD Foundation.
1994-05-24 10:09:53 +00:00
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_ntp.h"
#include "opt_ffclock.h"
1994-05-24 10:09:53 +00:00
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#ifdef FFCLOCK
#include <sys/lock.h>
#include <sys/mutex.h>
#endif
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/timeffc.h>
#include <sys/timepps.h>
#include <sys/timetc.h>
#include <sys/timex.h>
#include <sys/vdso.h>
Fix leap second processing by the kernel time keeping routines. Before, we would add/subtract the leap second when the system had been up for an even multiple of days, rather than at the end of the day, as a leap second is defined (at least wrt ntp). We do this by calculating the notion of UTC earlier in the loop, and passing that to get it adjusted. Any adjustments that ntp_update_second makes to this time are then transferred to boot time. We can't pass it either the boot time or the uptime because their sum is what determines when a leap second is needed. This code adds an extra assignment and two extra compare in the typical case, which is as cheap as I could made it. I have confirmed with this code the kernel time does the correct thing for both positive and negative leap seconds. Since the ntp interface doesn't allow for +2 or -2, those cases can't be tested (and the folks in the know here say there will never be a +2s or -2s leap event, but rather two +1s or -1s leap events). There will very likely be no leap seconds for a while, given how the earth is speeding up and slowing down, so there will be plenty of time for this fix to propigate. UT1-UTC is currently at "about -0.4s" and decrementing by .1s every 8 months or so. 6 * 8 is 48 months, or 4 years. -stable has different code, but a similar bug that was introduced about the time of the last leap second, which is why nobody has noticed until now. MFC After: 3 weeks Reviewed by: phk "Furthermore, leap seconds must die." -- Cato the Elder
2003-06-25 21:23:51 +00:00
/*
* A large step happens on boot. This constant detects such steps.
* It is relatively small so that ntp_update_second gets called enough
* in the typical 'missed a couple of seconds' case, but doesn't loop
* forever when the time step is large.
Fix leap second processing by the kernel time keeping routines. Before, we would add/subtract the leap second when the system had been up for an even multiple of days, rather than at the end of the day, as a leap second is defined (at least wrt ntp). We do this by calculating the notion of UTC earlier in the loop, and passing that to get it adjusted. Any adjustments that ntp_update_second makes to this time are then transferred to boot time. We can't pass it either the boot time or the uptime because their sum is what determines when a leap second is needed. This code adds an extra assignment and two extra compare in the typical case, which is as cheap as I could made it. I have confirmed with this code the kernel time does the correct thing for both positive and negative leap seconds. Since the ntp interface doesn't allow for +2 or -2, those cases can't be tested (and the folks in the know here say there will never be a +2s or -2s leap event, but rather two +1s or -1s leap events). There will very likely be no leap seconds for a while, given how the earth is speeding up and slowing down, so there will be plenty of time for this fix to propigate. UT1-UTC is currently at "about -0.4s" and decrementing by .1s every 8 months or so. 6 * 8 is 48 months, or 4 years. -stable has different code, but a similar bug that was introduced about the time of the last leap second, which is why nobody has noticed until now. MFC After: 3 weeks Reviewed by: phk "Furthermore, leap seconds must die." -- Cato the Elder
2003-06-25 21:23:51 +00:00
*/
#define LARGE_STEP 200
/*
* Implement a dummy timecounter which we can use until we get a real one
* in the air. This allows the console and other early stuff to use
* time services.
*/
static u_int
dummy_get_timecount(struct timecounter *tc)
{
static u_int now;
return (++now);
}
static struct timecounter dummy_timecounter = {
dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
};
struct timehands {
/* These fields must be initialized by the driver. */
struct timecounter *th_counter;
int64_t th_adjustment;
uint64_t th_scale;
u_int th_offset_count;
struct bintime th_offset;
struct timeval th_microtime;
struct timespec th_nanotime;
/* Fields not to be copied in tc_windup start with th_generation. */
volatile u_int th_generation;
struct timehands *th_next;
};
static struct timehands th0;
static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0};
static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9};
static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8};
static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7};
static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6};
static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5};
static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4};
static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3};
static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2};
static struct timehands th0 = {
&dummy_timecounter,
0,
(uint64_t)-1 / 1000000,
0,
{1, 0},
{0, 0},
{0, 0},
1,
&th1
};
static struct timehands *volatile timehands = &th0;
struct timecounter *timecounter = &dummy_timecounter;
static struct timecounter *timecounters = &dummy_timecounter;
int tc_min_ticktock_freq = 1;
volatile time_t time_second = 1;
volatile time_t time_uptime = 1;
struct bintime boottimebin;
struct timeval boottime;
static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD,
NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime");
SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
static SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, "");
static int timestepwarnings;
SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
&timestepwarnings, 0, "Log time steps");
struct bintime bt_timethreshold;
struct bintime bt_tickthreshold;
sbintime_t sbt_timethreshold;
sbintime_t sbt_tickthreshold;
struct bintime tc_tick_bt;
sbintime_t tc_tick_sbt;
int tc_precexp;
int tc_timepercentage = TC_DEFAULTPERC;
static int sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS);
SYSCTL_PROC(_kern_timecounter, OID_AUTO, alloweddeviation,
CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, 0,
sysctl_kern_timecounter_adjprecision, "I",
"Allowed time interval deviation in percents");
static void tc_windup(void);
static void cpu_tick_calibrate(int);
void dtrace_getnanotime(struct timespec *tsp);
static int
sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
{
#ifndef __mips__
#ifdef SCTL_MASK32
int tv[2];
if (req->flags & SCTL_MASK32) {
tv[0] = boottime.tv_sec;
tv[1] = boottime.tv_usec;
return SYSCTL_OUT(req, tv, sizeof(tv));
} else
#endif
#endif
return SYSCTL_OUT(req, &boottime, sizeof(boottime));
}
static int
sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
{
u_int ncount;
struct timecounter *tc = arg1;
ncount = tc->tc_get_timecount(tc);
return sysctl_handle_int(oidp, &ncount, 0, req);
}
static int
sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
{
uint64_t freq;
struct timecounter *tc = arg1;
freq = tc->tc_frequency;
return sysctl_handle_64(oidp, &freq, 0, req);
}
/*
* Return the difference between the timehands' counter value now and what
* was when we copied it to the timehands' offset_count.
*/
static __inline u_int
tc_delta(struct timehands *th)
{
struct timecounter *tc;
tc = th->th_counter;
return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
tc->tc_counter_mask);
}
/*
* Functions for reading the time. We have to loop until we are sure that
* the timehands that we operated on was not updated under our feet. See
* the comment in <sys/time.h> for a description of these 12 functions.
*/
#ifdef FFCLOCK
void
fbclock_binuptime(struct bintime *bt)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
bintime_addx(bt, th->th_scale * tc_delta(th));
} while (gen == 0 || gen != th->th_generation);
}
void
fbclock_nanouptime(struct timespec *tsp)
{
struct bintime bt;
fbclock_binuptime(&bt);
bintime2timespec(&bt, tsp);
}
void
fbclock_microuptime(struct timeval *tvp)
{
struct bintime bt;
fbclock_binuptime(&bt);
bintime2timeval(&bt, tvp);
}
void
fbclock_bintime(struct bintime *bt)
{
fbclock_binuptime(bt);
bintime_add(bt, &boottimebin);
}
void
fbclock_nanotime(struct timespec *tsp)
{
struct bintime bt;
fbclock_bintime(&bt);
bintime2timespec(&bt, tsp);
}
void
fbclock_microtime(struct timeval *tvp)
{
struct bintime bt;
fbclock_bintime(&bt);
bintime2timeval(&bt, tvp);
}
void
fbclock_getbinuptime(struct bintime *bt)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
} while (gen == 0 || gen != th->th_generation);
}
void
fbclock_getnanouptime(struct timespec *tsp)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
bintime2timespec(&th->th_offset, tsp);
} while (gen == 0 || gen != th->th_generation);
}
void
fbclock_getmicrouptime(struct timeval *tvp)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
bintime2timeval(&th->th_offset, tvp);
} while (gen == 0 || gen != th->th_generation);
}
void
fbclock_getbintime(struct bintime *bt)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
} while (gen == 0 || gen != th->th_generation);
bintime_add(bt, &boottimebin);
}
void
fbclock_getnanotime(struct timespec *tsp)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
*tsp = th->th_nanotime;
} while (gen == 0 || gen != th->th_generation);
}
void
fbclock_getmicrotime(struct timeval *tvp)
{
struct timehands *th;
unsigned int gen;
do {
th = timehands;
gen = th->th_generation;
*tvp = th->th_microtime;
} while (gen == 0 || gen != th->th_generation);
}
#else /* !FFCLOCK */
void
binuptime(struct bintime *bt)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
bintime_addx(bt, th->th_scale * tc_delta(th));
} while (gen == 0 || gen != th->th_generation);
}
void
nanouptime(struct timespec *tsp)
{
struct bintime bt;
binuptime(&bt);
bintime2timespec(&bt, tsp);
}
void
microuptime(struct timeval *tvp)
{
struct bintime bt;
binuptime(&bt);
bintime2timeval(&bt, tvp);
}
void
bintime(struct bintime *bt)
{
binuptime(bt);
bintime_add(bt, &boottimebin);
}
void
nanotime(struct timespec *tsp)
{
struct bintime bt;
bintime(&bt);
bintime2timespec(&bt, tsp);
}
void
microtime(struct timeval *tvp)
{
struct bintime bt;
bintime(&bt);
bintime2timeval(&bt, tvp);
}
void
getbinuptime(struct bintime *bt)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
} while (gen == 0 || gen != th->th_generation);
}
void
getnanouptime(struct timespec *tsp)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
bintime2timespec(&th->th_offset, tsp);
} while (gen == 0 || gen != th->th_generation);
}
void
getmicrouptime(struct timeval *tvp)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
bintime2timeval(&th->th_offset, tvp);
} while (gen == 0 || gen != th->th_generation);
}
void
getbintime(struct bintime *bt)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*bt = th->th_offset;
} while (gen == 0 || gen != th->th_generation);
bintime_add(bt, &boottimebin);
}
void
getnanotime(struct timespec *tsp)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*tsp = th->th_nanotime;
} while (gen == 0 || gen != th->th_generation);
}
void
getmicrotime(struct timeval *tvp)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*tvp = th->th_microtime;
} while (gen == 0 || gen != th->th_generation);
}
#endif /* FFCLOCK */
#ifdef FFCLOCK
/*
* Support for feed-forward synchronization algorithms. This is heavily inspired
* by the timehands mechanism but kept independent from it. *_windup() functions
* have some connection to avoid accessing the timecounter hardware more than
* necessary.
*/
/* Feed-forward clock estimates kept updated by the synchronization daemon. */
struct ffclock_estimate ffclock_estimate;
struct bintime ffclock_boottime; /* Feed-forward boot time estimate. */
uint32_t ffclock_status; /* Feed-forward clock status. */
int8_t ffclock_updated; /* New estimates are available. */
struct mtx ffclock_mtx; /* Mutex on ffclock_estimate. */
struct fftimehands {
struct ffclock_estimate cest;
struct bintime tick_time;
struct bintime tick_time_lerp;
ffcounter tick_ffcount;
uint64_t period_lerp;
volatile uint8_t gen;
struct fftimehands *next;
};
#define NUM_ELEMENTS(x) (sizeof(x) / sizeof(*x))
static struct fftimehands ffth[10];
static struct fftimehands *volatile fftimehands = ffth;
static void
ffclock_init(void)
{
struct fftimehands *cur;
struct fftimehands *last;
memset(ffth, 0, sizeof(ffth));
last = ffth + NUM_ELEMENTS(ffth) - 1;
for (cur = ffth; cur < last; cur++)
cur->next = cur + 1;
last->next = ffth;
ffclock_updated = 0;
ffclock_status = FFCLOCK_STA_UNSYNC;
mtx_init(&ffclock_mtx, "ffclock lock", NULL, MTX_DEF);
}
/*
* Reset the feed-forward clock estimates. Called from inittodr() to get things
* kick started and uses the timecounter nominal frequency as a first period
* estimate. Note: this function may be called several time just after boot.
* Note: this is the only function that sets the value of boot time for the
* monotonic (i.e. uptime) version of the feed-forward clock.
*/
void
ffclock_reset_clock(struct timespec *ts)
{
struct timecounter *tc;
struct ffclock_estimate cest;
tc = timehands->th_counter;
memset(&cest, 0, sizeof(struct ffclock_estimate));
timespec2bintime(ts, &ffclock_boottime);
timespec2bintime(ts, &(cest.update_time));
ffclock_read_counter(&cest.update_ffcount);
cest.leapsec_next = 0;
cest.period = ((1ULL << 63) / tc->tc_frequency) << 1;
cest.errb_abs = 0;
cest.errb_rate = 0;
cest.status = FFCLOCK_STA_UNSYNC;
cest.leapsec_total = 0;
cest.leapsec = 0;
mtx_lock(&ffclock_mtx);
bcopy(&cest, &ffclock_estimate, sizeof(struct ffclock_estimate));
ffclock_updated = INT8_MAX;
mtx_unlock(&ffclock_mtx);
printf("ffclock reset: %s (%llu Hz), time = %ld.%09lu\n", tc->tc_name,
(unsigned long long)tc->tc_frequency, (long)ts->tv_sec,
(unsigned long)ts->tv_nsec);
}
/*
* Sub-routine to convert a time interval measured in RAW counter units to time
* in seconds stored in bintime format.
* NOTE: bintime_mul requires u_int, but the value of the ffcounter may be
* larger than the max value of u_int (on 32 bit architecture). Loop to consume
* extra cycles.
*/
static void
ffclock_convert_delta(ffcounter ffdelta, uint64_t period, struct bintime *bt)
{
struct bintime bt2;
ffcounter delta, delta_max;
delta_max = (1ULL << (8 * sizeof(unsigned int))) - 1;
bintime_clear(bt);
do {
if (ffdelta > delta_max)
delta = delta_max;
else
delta = ffdelta;
bt2.sec = 0;
bt2.frac = period;
bintime_mul(&bt2, (unsigned int)delta);
bintime_add(bt, &bt2);
ffdelta -= delta;
} while (ffdelta > 0);
}
/*
* Update the fftimehands.
* Push the tick ffcount and time(s) forward based on current clock estimate.
* The conversion from ffcounter to bintime relies on the difference clock
* principle, whose accuracy relies on computing small time intervals. If a new
* clock estimate has been passed by the synchronisation daemon, make it
* current, and compute the linear interpolation for monotonic time if needed.
*/
static void
ffclock_windup(unsigned int delta)
{
struct ffclock_estimate *cest;
struct fftimehands *ffth;
struct bintime bt, gap_lerp;
ffcounter ffdelta;
uint64_t frac;
unsigned int polling;
uint8_t forward_jump, ogen;
/*
* Pick the next timehand, copy current ffclock estimates and move tick
* times and counter forward.
*/
forward_jump = 0;
ffth = fftimehands->next;
ogen = ffth->gen;
ffth->gen = 0;
cest = &ffth->cest;
bcopy(&fftimehands->cest, cest, sizeof(struct ffclock_estimate));
ffdelta = (ffcounter)delta;
ffth->period_lerp = fftimehands->period_lerp;
ffth->tick_time = fftimehands->tick_time;
ffclock_convert_delta(ffdelta, cest->period, &bt);
bintime_add(&ffth->tick_time, &bt);
ffth->tick_time_lerp = fftimehands->tick_time_lerp;
ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt);
bintime_add(&ffth->tick_time_lerp, &bt);
ffth->tick_ffcount = fftimehands->tick_ffcount + ffdelta;
/*
* Assess the status of the clock, if the last update is too old, it is
* likely the synchronisation daemon is dead and the clock is free
* running.
*/
if (ffclock_updated == 0) {
ffdelta = ffth->tick_ffcount - cest->update_ffcount;
ffclock_convert_delta(ffdelta, cest->period, &bt);
if (bt.sec > 2 * FFCLOCK_SKM_SCALE)
ffclock_status |= FFCLOCK_STA_UNSYNC;
}
/*
* If available, grab updated clock estimates and make them current.
* Recompute time at this tick using the updated estimates. The clock
* estimates passed the feed-forward synchronisation daemon may result
* in time conversion that is not monotonically increasing (just after
* the update). time_lerp is a particular linear interpolation over the
* synchronisation algo polling period that ensures monotonicity for the
* clock ids requesting it.
*/
if (ffclock_updated > 0) {
bcopy(&ffclock_estimate, cest, sizeof(struct ffclock_estimate));
ffdelta = ffth->tick_ffcount - cest->update_ffcount;
ffth->tick_time = cest->update_time;
ffclock_convert_delta(ffdelta, cest->period, &bt);
bintime_add(&ffth->tick_time, &bt);
/* ffclock_reset sets ffclock_updated to INT8_MAX */
if (ffclock_updated == INT8_MAX)
ffth->tick_time_lerp = ffth->tick_time;
if (bintime_cmp(&ffth->tick_time, &ffth->tick_time_lerp, >))
forward_jump = 1;
else
forward_jump = 0;
bintime_clear(&gap_lerp);
if (forward_jump) {
gap_lerp = ffth->tick_time;
bintime_sub(&gap_lerp, &ffth->tick_time_lerp);
} else {
gap_lerp = ffth->tick_time_lerp;
bintime_sub(&gap_lerp, &ffth->tick_time);
}
/*
* The reset from the RTC clock may be far from accurate, and
* reducing the gap between real time and interpolated time
* could take a very long time if the interpolated clock insists
* on strict monotonicity. The clock is reset under very strict
* conditions (kernel time is known to be wrong and
* synchronization daemon has been restarted recently.
* ffclock_boottime absorbs the jump to ensure boot time is
* correct and uptime functions stay consistent.
*/
if (((ffclock_status & FFCLOCK_STA_UNSYNC) == FFCLOCK_STA_UNSYNC) &&
((cest->status & FFCLOCK_STA_UNSYNC) == 0) &&
((cest->status & FFCLOCK_STA_WARMUP) == FFCLOCK_STA_WARMUP)) {
if (forward_jump)
bintime_add(&ffclock_boottime, &gap_lerp);
else
bintime_sub(&ffclock_boottime, &gap_lerp);
ffth->tick_time_lerp = ffth->tick_time;
bintime_clear(&gap_lerp);
}
ffclock_status = cest->status;
ffth->period_lerp = cest->period;
/*
* Compute corrected period used for the linear interpolation of
* time. The rate of linear interpolation is capped to 5000PPM
* (5ms/s).
*/
if (bintime_isset(&gap_lerp)) {
ffdelta = cest->update_ffcount;
ffdelta -= fftimehands->cest.update_ffcount;
ffclock_convert_delta(ffdelta, cest->period, &bt);
polling = bt.sec;
bt.sec = 0;
bt.frac = 5000000 * (uint64_t)18446744073LL;
bintime_mul(&bt, polling);
if (bintime_cmp(&gap_lerp, &bt, >))
gap_lerp = bt;
/* Approximate 1 sec by 1-(1/2^64) to ease arithmetic */
frac = 0;
if (gap_lerp.sec > 0) {
frac -= 1;
frac /= ffdelta / gap_lerp.sec;
}
frac += gap_lerp.frac / ffdelta;
if (forward_jump)
ffth->period_lerp += frac;
else
ffth->period_lerp -= frac;
}
ffclock_updated = 0;
}
if (++ogen == 0)
ogen = 1;
ffth->gen = ogen;
fftimehands = ffth;
}
/*
* Adjust the fftimehands when the timecounter is changed. Stating the obvious,
* the old and new hardware counter cannot be read simultaneously. tc_windup()
* does read the two counters 'back to back', but a few cycles are effectively
* lost, and not accumulated in tick_ffcount. This is a fairly radical
* operation for a feed-forward synchronization daemon, and it is its job to not
* pushing irrelevant data to the kernel. Because there is no locking here,
* simply force to ignore pending or next update to give daemon a chance to
* realize the counter has changed.
*/
static void
ffclock_change_tc(struct timehands *th)
{
struct fftimehands *ffth;
struct ffclock_estimate *cest;
struct timecounter *tc;
uint8_t ogen;
tc = th->th_counter;
ffth = fftimehands->next;
ogen = ffth->gen;
ffth->gen = 0;
cest = &ffth->cest;
bcopy(&(fftimehands->cest), cest, sizeof(struct ffclock_estimate));
cest->period = ((1ULL << 63) / tc->tc_frequency ) << 1;
cest->errb_abs = 0;
cest->errb_rate = 0;
cest->status |= FFCLOCK_STA_UNSYNC;
ffth->tick_ffcount = fftimehands->tick_ffcount;
ffth->tick_time_lerp = fftimehands->tick_time_lerp;
ffth->tick_time = fftimehands->tick_time;
ffth->period_lerp = cest->period;
/* Do not lock but ignore next update from synchronization daemon. */
ffclock_updated--;
if (++ogen == 0)
ogen = 1;
ffth->gen = ogen;
fftimehands = ffth;
}
/*
* Retrieve feed-forward counter and time of last kernel tick.
*/
void
ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags)
{
struct fftimehands *ffth;
uint8_t gen;
/*
* No locking but check generation has not changed. Also need to make
* sure ffdelta is positive, i.e. ffcount > tick_ffcount.
*/
do {
ffth = fftimehands;
gen = ffth->gen;
if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP)
*bt = ffth->tick_time_lerp;
else
*bt = ffth->tick_time;
*ffcount = ffth->tick_ffcount;
} while (gen == 0 || gen != ffth->gen);
}
/*
* Absolute clock conversion. Low level function to convert ffcounter to
* bintime. The ffcounter is converted using the current ffclock period estimate
* or the "interpolated period" to ensure monotonicity.
* NOTE: this conversion may have been deferred, and the clock updated since the
* hardware counter has been read.
*/
void
ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags)
{
struct fftimehands *ffth;
struct bintime bt2;
ffcounter ffdelta;
uint8_t gen;
/*
* No locking but check generation has not changed. Also need to make
* sure ffdelta is positive, i.e. ffcount > tick_ffcount.
*/
do {
ffth = fftimehands;
gen = ffth->gen;
if (ffcount > ffth->tick_ffcount)
ffdelta = ffcount - ffth->tick_ffcount;
else
ffdelta = ffth->tick_ffcount - ffcount;
if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) {
*bt = ffth->tick_time_lerp;
ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt2);
} else {
*bt = ffth->tick_time;
ffclock_convert_delta(ffdelta, ffth->cest.period, &bt2);
}
if (ffcount > ffth->tick_ffcount)
bintime_add(bt, &bt2);
else
bintime_sub(bt, &bt2);
} while (gen == 0 || gen != ffth->gen);
}
/*
* Difference clock conversion.
* Low level function to Convert a time interval measured in RAW counter units
* into bintime. The difference clock allows measuring small intervals much more
* reliably than the absolute clock.
*/
void
ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt)
{
struct fftimehands *ffth;
uint8_t gen;
/* No locking but check generation has not changed. */
do {
ffth = fftimehands;
gen = ffth->gen;
ffclock_convert_delta(ffdelta, ffth->cest.period, bt);
} while (gen == 0 || gen != ffth->gen);
}
/*
* Access to current ffcounter value.
*/
void
ffclock_read_counter(ffcounter *ffcount)
{
struct timehands *th;
struct fftimehands *ffth;
unsigned int gen, delta;
/*
* ffclock_windup() called from tc_windup(), safe to rely on
* th->th_generation only, for correct delta and ffcounter.
*/
do {
th = timehands;
gen = th->th_generation;
ffth = fftimehands;
delta = tc_delta(th);
*ffcount = ffth->tick_ffcount;
} while (gen == 0 || gen != th->th_generation);
*ffcount += delta;
}
void
binuptime(struct bintime *bt)
{
binuptime_fromclock(bt, sysclock_active);
}
void
nanouptime(struct timespec *tsp)
{
nanouptime_fromclock(tsp, sysclock_active);
}
void
microuptime(struct timeval *tvp)
{
microuptime_fromclock(tvp, sysclock_active);
}
void
bintime(struct bintime *bt)
{
bintime_fromclock(bt, sysclock_active);
}
void
nanotime(struct timespec *tsp)
{
nanotime_fromclock(tsp, sysclock_active);
}
void
microtime(struct timeval *tvp)
{
microtime_fromclock(tvp, sysclock_active);
}
void
getbinuptime(struct bintime *bt)
{
getbinuptime_fromclock(bt, sysclock_active);
}
void
getnanouptime(struct timespec *tsp)
{
getnanouptime_fromclock(tsp, sysclock_active);
}
void
getmicrouptime(struct timeval *tvp)
{
getmicrouptime_fromclock(tvp, sysclock_active);
}
void
getbintime(struct bintime *bt)
{
getbintime_fromclock(bt, sysclock_active);
}
void
getnanotime(struct timespec *tsp)
{
getnanotime_fromclock(tsp, sysclock_active);
}
void
getmicrotime(struct timeval *tvp)
{
getmicrouptime_fromclock(tvp, sysclock_active);
}
#endif /* FFCLOCK */
/*
* This is a clone of getnanotime and used for walltimestamps.
* The dtrace_ prefix prevents fbt from creating probes for
* it so walltimestamp can be safely used in all fbt probes.
*/
void
dtrace_getnanotime(struct timespec *tsp)
{
struct timehands *th;
u_int gen;
do {
th = timehands;
gen = th->th_generation;
*tsp = th->th_nanotime;
} while (gen == 0 || gen != th->th_generation);
}
/*
* System clock currently providing time to the system. Modifiable via sysctl
* when the FFCLOCK option is defined.
*/
int sysclock_active = SYSCLOCK_FBCK;
/* Internal NTP status and error estimates. */
extern int time_status;
extern long time_esterror;
/*
* Take a snapshot of sysclock data which can be used to compare system clocks
* and generate timestamps after the fact.
*/
void
sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
{
struct fbclock_info *fbi;
struct timehands *th;
struct bintime bt;
unsigned int delta, gen;
#ifdef FFCLOCK
ffcounter ffcount;
struct fftimehands *ffth;
struct ffclock_info *ffi;
struct ffclock_estimate cest;
ffi = &clock_snap->ff_info;
#endif
fbi = &clock_snap->fb_info;
delta = 0;
do {
th = timehands;
gen = th->th_generation;
fbi->th_scale = th->th_scale;
fbi->tick_time = th->th_offset;
#ifdef FFCLOCK
ffth = fftimehands;
ffi->tick_time = ffth->tick_time_lerp;
ffi->tick_time_lerp = ffth->tick_time_lerp;
ffi->period = ffth->cest.period;
ffi->period_lerp = ffth->period_lerp;
clock_snap->ffcount = ffth->tick_ffcount;
cest = ffth->cest;
#endif
if (!fast)
delta = tc_delta(th);
} while (gen == 0 || gen != th->th_generation);
clock_snap->delta = delta;
clock_snap->sysclock_active = sysclock_active;
/* Record feedback clock status and error. */
clock_snap->fb_info.status = time_status;
/* XXX: Very crude estimate of feedback clock error. */
bt.sec = time_esterror / 1000000;
bt.frac = ((time_esterror - bt.sec) * 1000000) *
(uint64_t)18446744073709ULL;
clock_snap->fb_info.error = bt;
#ifdef FFCLOCK
if (!fast)
clock_snap->ffcount += delta;
/* Record feed-forward clock leap second adjustment. */
ffi->leapsec_adjustment = cest.leapsec_total;
if (clock_snap->ffcount > cest.leapsec_next)
ffi->leapsec_adjustment -= cest.leapsec;
/* Record feed-forward clock status and error. */
clock_snap->ff_info.status = cest.status;
ffcount = clock_snap->ffcount - cest.update_ffcount;
ffclock_convert_delta(ffcount, cest.period, &bt);
/* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s]. */
bintime_mul(&bt, cest.errb_rate * (uint64_t)18446744073709ULL);
/* 18446744073 = int(2^64 / 1e9), since err_abs in [ns]. */
bintime_addx(&bt, cest.errb_abs * (uint64_t)18446744073ULL);
clock_snap->ff_info.error = bt;
#endif
}
/*
* Convert a sysclock snapshot into a struct bintime based on the specified
* clock source and flags.
*/
int
sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
int whichclock, uint32_t flags)
{
#ifdef FFCLOCK
struct bintime bt2;
uint64_t period;
#endif
switch (whichclock) {
case SYSCLOCK_FBCK:
*bt = cs->fb_info.tick_time;
/* If snapshot was created with !fast, delta will be >0. */
if (cs->delta > 0)
bintime_addx(bt, cs->fb_info.th_scale * cs->delta);
if ((flags & FBCLOCK_UPTIME) == 0)
bintime_add(bt, &boottimebin);
break;
#ifdef FFCLOCK
case SYSCLOCK_FFWD:
if (flags & FFCLOCK_LERP) {
*bt = cs->ff_info.tick_time_lerp;
period = cs->ff_info.period_lerp;
} else {
*bt = cs->ff_info.tick_time;
period = cs->ff_info.period;
}
/* If snapshot was created with !fast, delta will be >0. */
if (cs->delta > 0) {
ffclock_convert_delta(cs->delta, period, &bt2);
bintime_add(bt, &bt2);
}
/* Leap second adjustment. */
if (flags & FFCLOCK_LEAPSEC)
bt->sec -= cs->ff_info.leapsec_adjustment;
/* Boot time adjustment, for uptime/monotonic clocks. */
if (flags & FFCLOCK_UPTIME)
bintime_sub(bt, &ffclock_boottime);
break;
#endif
default:
return (EINVAL);
break;
}
return (0);
}
/*
* Initialize a new timecounter and possibly use it.
*/
void
tc_init(struct timecounter *tc)
{
u_int u;
struct sysctl_oid *tc_root;
u = tc->tc_frequency / tc->tc_counter_mask;
/* XXX: We need some margin here, 10% is a guess */
u *= 11;
u /= 10;
if (u > hz && tc->tc_quality >= 0) {
tc->tc_quality = -2000;
if (bootverbose) {
printf("Timecounter \"%s\" frequency %ju Hz",
tc->tc_name, (uintmax_t)tc->tc_frequency);
printf(" -- Insufficient hz, needs at least %u\n", u);
}
} else if (tc->tc_quality >= 0 || bootverbose) {
printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
tc->tc_name, (uintmax_t)tc->tc_frequency,
tc->tc_quality);
}
tc->tc_next = timecounters;
timecounters = tc;
/*
* Set up sysctl tree for this counter.
*/
tc_root = SYSCTL_ADD_NODE(NULL,
SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
CTLFLAG_RW, 0, "timecounter description");
SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
"mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
"mask for implemented bits");
SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
"counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc),
sysctl_kern_timecounter_get, "IU", "current timecounter value");
SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
"frequency", CTLTYPE_U64 | CTLFLAG_RD, tc, sizeof(*tc),
sysctl_kern_timecounter_freq, "QU", "timecounter frequency");
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
"quality", CTLFLAG_RD, &(tc->tc_quality), 0,
"goodness of time counter");
/*
* Never automatically use a timecounter with negative quality.
* Even though we run on the dummy counter, switching here may be
* worse since this timecounter may not be monotonous.
*/
if (tc->tc_quality < 0)
return;
if (tc->tc_quality < timecounter->tc_quality)
return;
if (tc->tc_quality == timecounter->tc_quality &&
tc->tc_frequency < timecounter->tc_frequency)
return;
(void)tc->tc_get_timecount(tc);
(void)tc->tc_get_timecount(tc);
timecounter = tc;
}
/* Report the frequency of the current timecounter. */
uint64_t
tc_getfrequency(void)
{
return (timehands->th_counter->tc_frequency);
}
/*
* Step our concept of UTC. This is done by modifying our estimate of
* when we booted.
* XXX: not locked.
*/
void
tc_setclock(struct timespec *ts)
{
struct timespec tbef, taft;
struct bintime bt, bt2;
cpu_tick_calibrate(1);
nanotime(&tbef);
timespec2bintime(ts, &bt);
binuptime(&bt2);
bintime_sub(&bt, &bt2);
bintime_add(&bt2, &boottimebin);
boottimebin = bt;
bintime2timeval(&bt, &boottime);
/* XXX fiddle all the little crinkly bits around the fiords... */
tc_windup();
nanotime(&taft);
if (timestepwarnings) {
log(LOG_INFO,
"Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
(intmax_t)tbef.tv_sec, tbef.tv_nsec,
(intmax_t)taft.tv_sec, taft.tv_nsec,
(intmax_t)ts->tv_sec, ts->tv_nsec);
}
cpu_tick_calibrate(1);
}
/*
* Initialize the next struct timehands in the ring and make
* it the active timehands. Along the way we might switch to a different
* timecounter and/or do seconds processing in NTP. Slightly magic.
*/
static void
tc_windup(void)
{
struct bintime bt;
struct timehands *th, *tho;
uint64_t scale;
u_int delta, ncount, ogen;
int i;
Fix leap second processing by the kernel time keeping routines. Before, we would add/subtract the leap second when the system had been up for an even multiple of days, rather than at the end of the day, as a leap second is defined (at least wrt ntp). We do this by calculating the notion of UTC earlier in the loop, and passing that to get it adjusted. Any adjustments that ntp_update_second makes to this time are then transferred to boot time. We can't pass it either the boot time or the uptime because their sum is what determines when a leap second is needed. This code adds an extra assignment and two extra compare in the typical case, which is as cheap as I could made it. I have confirmed with this code the kernel time does the correct thing for both positive and negative leap seconds. Since the ntp interface doesn't allow for +2 or -2, those cases can't be tested (and the folks in the know here say there will never be a +2s or -2s leap event, but rather two +1s or -1s leap events). There will very likely be no leap seconds for a while, given how the earth is speeding up and slowing down, so there will be plenty of time for this fix to propigate. UT1-UTC is currently at "about -0.4s" and decrementing by .1s every 8 months or so. 6 * 8 is 48 months, or 4 years. -stable has different code, but a similar bug that was introduced about the time of the last leap second, which is why nobody has noticed until now. MFC After: 3 weeks Reviewed by: phk "Furthermore, leap seconds must die." -- Cato the Elder
2003-06-25 21:23:51 +00:00
time_t t;
/*
* Make the next timehands a copy of the current one, but do not
* overwrite the generation or next pointer. While we update
* the contents, the generation must be zero.
*/
tho = timehands;
th = tho->th_next;
ogen = th->th_generation;
th->th_generation = 0;
bcopy(tho, th, offsetof(struct timehands, th_generation));
/*
* Capture a timecounter delta on the current timecounter and if
* changing timecounters, a counter value from the new timecounter.
* Update the offset fields accordingly.
*/
delta = tc_delta(th);
if (th->th_counter != timecounter)
ncount = timecounter->tc_get_timecount(timecounter);
else
ncount = 0;
#ifdef FFCLOCK
ffclock_windup(delta);
#endif
th->th_offset_count += delta;
th->th_offset_count &= th->th_counter->tc_counter_mask;
while (delta > th->th_counter->tc_frequency) {
/* Eat complete unadjusted seconds. */
delta -= th->th_counter->tc_frequency;
th->th_offset.sec++;
}
if ((delta > th->th_counter->tc_frequency / 2) &&
(th->th_scale * delta < ((uint64_t)1 << 63))) {
/* The product th_scale * delta just barely overflows. */
th->th_offset.sec++;
}
bintime_addx(&th->th_offset, th->th_scale * delta);
/*
* Hardware latching timecounters may not generate interrupts on
* PPS events, so instead we poll them. There is a finite risk that
* the hardware might capture a count which is later than the one we
* got above, and therefore possibly in the next NTP second which might
* have a different rate than the current NTP second. It doesn't
* matter in practice.
*/
if (tho->th_counter->tc_poll_pps)
tho->th_counter->tc_poll_pps(tho->th_counter);
/*
* Deal with NTP second processing. The for loop normally
* iterates at most once, but in extreme situations it might
* keep NTP sane if timeouts are not run for several seconds.
* At boot, the time step can be large when the TOD hardware
* has been read, so on really large steps, we call
* ntp_update_second only twice. We need to call it twice in
* case we missed a leap second.
Fix leap second processing by the kernel time keeping routines. Before, we would add/subtract the leap second when the system had been up for an even multiple of days, rather than at the end of the day, as a leap second is defined (at least wrt ntp). We do this by calculating the notion of UTC earlier in the loop, and passing that to get it adjusted. Any adjustments that ntp_update_second makes to this time are then transferred to boot time. We can't pass it either the boot time or the uptime because their sum is what determines when a leap second is needed. This code adds an extra assignment and two extra compare in the typical case, which is as cheap as I could made it. I have confirmed with this code the kernel time does the correct thing for both positive and negative leap seconds. Since the ntp interface doesn't allow for +2 or -2, those cases can't be tested (and the folks in the know here say there will never be a +2s or -2s leap event, but rather two +1s or -1s leap events). There will very likely be no leap seconds for a while, given how the earth is speeding up and slowing down, so there will be plenty of time for this fix to propigate. UT1-UTC is currently at "about -0.4s" and decrementing by .1s every 8 months or so. 6 * 8 is 48 months, or 4 years. -stable has different code, but a similar bug that was introduced about the time of the last leap second, which is why nobody has noticed until now. MFC After: 3 weeks Reviewed by: phk "Furthermore, leap seconds must die." -- Cato the Elder
2003-06-25 21:23:51 +00:00
*/
bt = th->th_offset;
bintime_add(&bt, &boottimebin);
i = bt.sec - tho->th_microtime.tv_sec;
if (i > LARGE_STEP)
i = 2;
for (; i > 0; i--) {
Fix leap second processing by the kernel time keeping routines. Before, we would add/subtract the leap second when the system had been up for an even multiple of days, rather than at the end of the day, as a leap second is defined (at least wrt ntp). We do this by calculating the notion of UTC earlier in the loop, and passing that to get it adjusted. Any adjustments that ntp_update_second makes to this time are then transferred to boot time. We can't pass it either the boot time or the uptime because their sum is what determines when a leap second is needed. This code adds an extra assignment and two extra compare in the typical case, which is as cheap as I could made it. I have confirmed with this code the kernel time does the correct thing for both positive and negative leap seconds. Since the ntp interface doesn't allow for +2 or -2, those cases can't be tested (and the folks in the know here say there will never be a +2s or -2s leap event, but rather two +1s or -1s leap events). There will very likely be no leap seconds for a while, given how the earth is speeding up and slowing down, so there will be plenty of time for this fix to propigate. UT1-UTC is currently at "about -0.4s" and decrementing by .1s every 8 months or so. 6 * 8 is 48 months, or 4 years. -stable has different code, but a similar bug that was introduced about the time of the last leap second, which is why nobody has noticed until now. MFC After: 3 weeks Reviewed by: phk "Furthermore, leap seconds must die." -- Cato the Elder
2003-06-25 21:23:51 +00:00
t = bt.sec;
ntp_update_second(&th->th_adjustment, &bt.sec);
if (bt.sec != t)
boottimebin.sec += bt.sec - t;
}
/* Update the UTC timestamps used by the get*() functions. */
/* XXX shouldn't do this here. Should force non-`get' versions. */
bintime2timeval(&bt, &th->th_microtime);
bintime2timespec(&bt, &th->th_nanotime);
/* Now is a good time to change timecounters. */
if (th->th_counter != timecounter) {
#ifndef __arm__
if ((timecounter->tc_flags & TC_FLAGS_C3STOP) != 0)
cpu_disable_deep_sleep++;
if ((th->th_counter->tc_flags & TC_FLAGS_C3STOP) != 0)
cpu_disable_deep_sleep--;
#endif
th->th_counter = timecounter;
th->th_offset_count = ncount;
tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
(((uint64_t)timecounter->tc_counter_mask + 1) / 3));
#ifdef FFCLOCK
ffclock_change_tc(th);
#endif
}
/*-
* Recalculate the scaling factor. We want the number of 1/2^64
* fractions of a second per period of the hardware counter, taking
* into account the th_adjustment factor which the NTP PLL/adjtime(2)
* processing provides us with.
*
* The th_adjustment is nanoseconds per second with 32 bit binary
2003-07-02 08:01:52 +00:00
* fraction and we want 64 bit binary fraction of second:
*
* x = a * 2^32 / 10^9 = a * 4.294967296
*
* The range of th_adjustment is +/- 5000PPM so inside a 64bit int
* we can only multiply by about 850 without overflowing, that
* leaves no suitably precise fractions for multiply before divide.
*
* Divide before multiply with a fraction of 2199/512 results in a
* systematic undercompensation of 10PPM of th_adjustment. On a
* 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
*
* We happily sacrifice the lowest of the 64 bits of our result
* to the goddess of code clarity.
*
*/
scale = (uint64_t)1 << 63;
scale += (th->th_adjustment / 1024) * 2199;
scale /= th->th_counter->tc_frequency;
th->th_scale = scale * 2;
/*
* Now that the struct timehands is again consistent, set the new
* generation number, making sure to not make it zero.
*/
if (++ogen == 0)
ogen = 1;
th->th_generation = ogen;
/* Go live with the new struct timehands. */
#ifdef FFCLOCK
switch (sysclock_active) {
case SYSCLOCK_FBCK:
#endif
time_second = th->th_microtime.tv_sec;
time_uptime = th->th_offset.sec;
#ifdef FFCLOCK
break;
case SYSCLOCK_FFWD:
time_second = fftimehands->tick_time_lerp.sec;
time_uptime = fftimehands->tick_time_lerp.sec - ffclock_boottime.sec;
break;
}
#endif
timehands = th;
timekeep_push_vdso();
}
/* Report or change the active timecounter hardware. */
static int
sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
{
char newname[32];
struct timecounter *newtc, *tc;
int error;
tc = timecounter;
strlcpy(newname, tc->tc_name, sizeof(newname));
error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
if (error != 0 || req->newptr == NULL ||
strcmp(newname, tc->tc_name) == 0)
return (error);
for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
if (strcmp(newname, newtc->tc_name) != 0)
continue;
/* Warm up new timecounter. */
(void)newtc->tc_get_timecount(newtc);
(void)newtc->tc_get_timecount(newtc);
timecounter = newtc;
timekeep_push_vdso();
return (0);
}
return (EINVAL);
}
SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
0, 0, sysctl_kern_timecounter_hardware, "A",
"Timecounter hardware selected");
/* Report or change the active timecounter hardware. */
static int
sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
{
char buf[32], *spc;
struct timecounter *tc;
int error;
spc = "";
error = 0;
for (tc = timecounters; error == 0 && tc != NULL; tc = tc->tc_next) {
sprintf(buf, "%s%s(%d)",
spc, tc->tc_name, tc->tc_quality);
error = SYSCTL_OUT(req, buf, strlen(buf));
spc = " ";
}
return (error);
}
SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
0, 0, sysctl_kern_timecounter_choice, "A", "Timecounter hardware detected");
/*
* RFC 2783 PPS-API implementation.
*/
static int
pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps)
{
int err, timo;
pps_seq_t aseq, cseq;
struct timeval tv;
if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
return (EINVAL);
/*
* If no timeout is requested, immediately return whatever values were
* most recently captured. If timeout seconds is -1, that's a request
* to block without a timeout. WITNESS won't let us sleep forever
* without a lock (we really don't need a lock), so just repeatedly
* sleep a long time.
*/
if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) {
if (fapi->timeout.tv_sec == -1)
timo = 0x7fffffff;
else {
tv.tv_sec = fapi->timeout.tv_sec;
tv.tv_usec = fapi->timeout.tv_nsec / 1000;
timo = tvtohz(&tv);
}
aseq = pps->ppsinfo.assert_sequence;
cseq = pps->ppsinfo.clear_sequence;
while (aseq == pps->ppsinfo.assert_sequence &&
cseq == pps->ppsinfo.clear_sequence) {
err = tsleep(pps, PCATCH, "ppsfch", timo);
if (err == EWOULDBLOCK && fapi->timeout.tv_sec == -1) {
continue;
} else if (err != 0) {
return (err);
}
}
}
pps->ppsinfo.current_mode = pps->ppsparam.mode;
fapi->pps_info_buf = pps->ppsinfo;
return (0);
}
int
pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
{
pps_params_t *app;
struct pps_fetch_args *fapi;
#ifdef FFCLOCK
struct pps_fetch_ffc_args *fapi_ffc;
#endif
#ifdef PPS_SYNC
struct pps_kcbind_args *kapi;
#endif
2004-08-14 08:33:49 +00:00
KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
switch (cmd) {
case PPS_IOC_CREATE:
return (0);
case PPS_IOC_DESTROY:
return (0);
case PPS_IOC_SETPARAMS:
app = (pps_params_t *)data;
if (app->mode & ~pps->ppscap)
return (EINVAL);
#ifdef FFCLOCK
/* Ensure only a single clock is selected for ffc timestamp. */
if ((app->mode & PPS_TSCLK_MASK) == PPS_TSCLK_MASK)
return (EINVAL);
#endif
pps->ppsparam = *app;
return (0);
case PPS_IOC_GETPARAMS:
app = (pps_params_t *)data;
*app = pps->ppsparam;
app->api_version = PPS_API_VERS_1;
return (0);
case PPS_IOC_GETCAP:
*(int*)data = pps->ppscap;
return (0);
case PPS_IOC_FETCH:
fapi = (struct pps_fetch_args *)data;
return (pps_fetch(fapi, pps));
#ifdef FFCLOCK
case PPS_IOC_FETCH_FFCOUNTER:
fapi_ffc = (struct pps_fetch_ffc_args *)data;
if (fapi_ffc->tsformat && fapi_ffc->tsformat !=
PPS_TSFMT_TSPEC)
return (EINVAL);
if (fapi_ffc->timeout.tv_sec || fapi_ffc->timeout.tv_nsec)
return (EOPNOTSUPP);
pps->ppsinfo_ffc.current_mode = pps->ppsparam.mode;
fapi_ffc->pps_info_buf_ffc = pps->ppsinfo_ffc;
/* Overwrite timestamps if feedback clock selected. */
switch (pps->ppsparam.mode & PPS_TSCLK_MASK) {
case PPS_TSCLK_FBCK:
fapi_ffc->pps_info_buf_ffc.assert_timestamp =
pps->ppsinfo.assert_timestamp;
fapi_ffc->pps_info_buf_ffc.clear_timestamp =
pps->ppsinfo.clear_timestamp;
break;
case PPS_TSCLK_FFWD:
break;
default:
break;
}
return (0);
#endif /* FFCLOCK */
case PPS_IOC_KCBIND:
#ifdef PPS_SYNC
kapi = (struct pps_kcbind_args *)data;
/* XXX Only root should be able to do this */
if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
return (EINVAL);
if (kapi->kernel_consumer != PPS_KC_HARDPPS)
return (EINVAL);
if (kapi->edge & ~pps->ppscap)
return (EINVAL);
pps->kcmode = kapi->edge;
return (0);
#else
return (EOPNOTSUPP);
#endif
default:
2005-03-26 20:04:28 +00:00
return (ENOIOCTL);
}
}
void
pps_init(struct pps_state *pps)
{
pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT;
if (pps->ppscap & PPS_CAPTUREASSERT)
pps->ppscap |= PPS_OFFSETASSERT;
if (pps->ppscap & PPS_CAPTURECLEAR)
pps->ppscap |= PPS_OFFSETCLEAR;
#ifdef FFCLOCK
pps->ppscap |= PPS_TSCLK_MASK;
#endif
}
void
pps_capture(struct pps_state *pps)
{
struct timehands *th;
2004-08-14 08:33:49 +00:00
KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
th = timehands;
pps->capgen = th->th_generation;
pps->capth = th;
#ifdef FFCLOCK
pps->capffth = fftimehands;
#endif
pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
if (pps->capgen != th->th_generation)
pps->capgen = 0;
}
void
pps_event(struct pps_state *pps, int event)
{
struct bintime bt;
struct timespec ts, *tsp, *osp;
u_int tcount, *pcount;
int foff, fhard;
pps_seq_t *pseq;
#ifdef FFCLOCK
struct timespec *tsp_ffc;
pps_seq_t *pseq_ffc;
ffcounter *ffcount;
#endif
2004-08-14 08:33:49 +00:00
KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
/* If the timecounter was wound up underneath us, bail out. */
if (pps->capgen == 0 || pps->capgen != pps->capth->th_generation)
return;
/* Things would be easier with arrays. */
if (event == PPS_CAPTUREASSERT) {
tsp = &pps->ppsinfo.assert_timestamp;
osp = &pps->ppsparam.assert_offset;
foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
fhard = pps->kcmode & PPS_CAPTUREASSERT;
pcount = &pps->ppscount[0];
pseq = &pps->ppsinfo.assert_sequence;
#ifdef FFCLOCK
ffcount = &pps->ppsinfo_ffc.assert_ffcount;
tsp_ffc = &pps->ppsinfo_ffc.assert_timestamp;
pseq_ffc = &pps->ppsinfo_ffc.assert_sequence;
#endif
} else {
tsp = &pps->ppsinfo.clear_timestamp;
osp = &pps->ppsparam.clear_offset;
foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
fhard = pps->kcmode & PPS_CAPTURECLEAR;
pcount = &pps->ppscount[1];
pseq = &pps->ppsinfo.clear_sequence;
#ifdef FFCLOCK
ffcount = &pps->ppsinfo_ffc.clear_ffcount;
tsp_ffc = &pps->ppsinfo_ffc.clear_timestamp;
pseq_ffc = &pps->ppsinfo_ffc.clear_sequence;
#endif
}
/*
* If the timecounter changed, we cannot compare the count values, so
* we have to drop the rest of the PPS-stuff until the next event.
*/
if (pps->ppstc != pps->capth->th_counter) {
pps->ppstc = pps->capth->th_counter;
*pcount = pps->capcount;
pps->ppscount[2] = pps->capcount;
return;
}
/* Convert the count to a timespec. */
tcount = pps->capcount - pps->capth->th_offset_count;
tcount &= pps->capth->th_counter->tc_counter_mask;
bt = pps->capth->th_offset;
bintime_addx(&bt, pps->capth->th_scale * tcount);
bintime_add(&bt, &boottimebin);
bintime2timespec(&bt, &ts);
/* If the timecounter was wound up underneath us, bail out. */
if (pps->capgen != pps->capth->th_generation)
return;
*pcount = pps->capcount;
(*pseq)++;
*tsp = ts;
if (foff) {
timespecadd(tsp, osp);
if (tsp->tv_nsec < 0) {
tsp->tv_nsec += 1000000000;
tsp->tv_sec -= 1;
}
}
#ifdef FFCLOCK
*ffcount = pps->capffth->tick_ffcount + tcount;
bt = pps->capffth->tick_time;
ffclock_convert_delta(tcount, pps->capffth->cest.period, &bt);
bintime_add(&bt, &pps->capffth->tick_time);
bintime2timespec(&bt, &ts);
(*pseq_ffc)++;
*tsp_ffc = ts;
#endif
#ifdef PPS_SYNC
if (fhard) {
uint64_t scale;
/*
* Feed the NTP PLL/FLL.
* The FLL wants to know how many (hardware) nanoseconds
* elapsed since the previous event.
*/
tcount = pps->capcount - pps->ppscount[2];
pps->ppscount[2] = pps->capcount;
tcount &= pps->capth->th_counter->tc_counter_mask;
scale = (uint64_t)1 << 63;
scale /= pps->capth->th_counter->tc_frequency;
scale *= 2;
bt.sec = 0;
bt.frac = 0;
bintime_addx(&bt, scale * tcount);
bintime2timespec(&bt, &ts);
hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
}
#endif
/* Wakeup anyone sleeping in pps_fetch(). */
wakeup(pps);
}
/*
* Timecounters need to be updated every so often to prevent the hardware
* counter from overflowing. Updating also recalculates the cached values
* used by the get*() family of functions, so their precision depends on
* the update frequency.
*/
static int tc_tick;
SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0,
2010-11-14 16:10:15 +00:00
"Approximate number of hardclock ticks in a millisecond");
void
tc_ticktock(int cnt)
{
static int count;
count += cnt;
if (count < tc_tick)
return;
count = 0;
tc_windup();
}
static void __inline
tc_adjprecision(void)
{
int t;
if (tc_timepercentage > 0) {
t = (99 + tc_timepercentage) / tc_timepercentage;
tc_precexp = fls(t + (t >> 1)) - 1;
FREQ2BT(hz / tc_tick, &bt_timethreshold);
FREQ2BT(hz, &bt_tickthreshold);
bintime_shift(&bt_timethreshold, tc_precexp);
bintime_shift(&bt_tickthreshold, tc_precexp);
} else {
tc_precexp = 31;
bt_timethreshold.sec = INT_MAX;
bt_timethreshold.frac = ~(uint64_t)0;
bt_tickthreshold = bt_timethreshold;
}
sbt_timethreshold = bttosbt(bt_timethreshold);
sbt_tickthreshold = bttosbt(bt_tickthreshold);
}
static int
sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS)
{
int error, val;
val = tc_timepercentage;
error = sysctl_handle_int(oidp, &val, 0, req);
if (error != 0 || req->newptr == NULL)
return (error);
tc_timepercentage = val;
if (cold)
goto done;
tc_adjprecision();
done:
return (0);
}
static void
inittimecounter(void *dummy)
{
u_int p;
int tick_rate;
/*
* Set the initial timeout to
* max(1, <approx. number of hardclock ticks in a millisecond>).
* People should probably not use the sysctl to set the timeout
* to smaller than its inital value, since that value is the
* smallest reasonable one. If they want better timestamps they
* should use the non-"get"* functions.
*/
if (hz > 1000)
tc_tick = (hz + 500) / 1000;
else
tc_tick = 1;
tc_adjprecision();
FREQ2BT(hz, &tick_bt);
tick_sbt = bttosbt(tick_bt);
tick_rate = hz / tc_tick;
FREQ2BT(tick_rate, &tc_tick_bt);
tc_tick_sbt = bttosbt(tc_tick_bt);
p = (tc_tick * 1000000) / hz;
printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
#ifdef FFCLOCK
ffclock_init();
#endif
/* warm up new timecounter (again) and get rolling. */
(void)timecounter->tc_get_timecount(timecounter);
(void)timecounter->tc_get_timecount(timecounter);
tc_windup();
}
SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL);
/* Cpu tick handling -------------------------------------------------*/
static int cpu_tick_variable;
static uint64_t cpu_tick_frequency;
2006-03-07 22:17:26 +00:00
static uint64_t
tc_cpu_ticks(void)
{
static uint64_t base;
static unsigned last;
unsigned u;
struct timecounter *tc;
tc = timehands->th_counter;
u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
if (u < last)
2006-03-04 06:07:26 +00:00
base += (uint64_t)tc->tc_counter_mask + 1;
last = u;
return (u + base);
}
Refactor timer management code with priority to one-shot operation mode. The main goal of this is to generate timer interrupts only when there is some work to do. When CPU is busy interrupts are generating at full rate of hz + stathz to fullfill scheduler and timekeeping requirements. But when CPU is idle, only minimum set of interrupts (down to 8 interrupts per second per CPU now), needed to handle scheduled callouts is executed. This allows significantly increase idle CPU sleep time, increasing effect of static power-saving technologies. Also it should reduce host CPU load on virtualized systems, when guest system is idle. There is set of tunables, also available as writable sysctls, allowing to control wanted event timer subsystem behavior: kern.eventtimer.timer - allows to choose event timer hardware to use. On x86 there is up to 4 different kinds of timers. Depending on whether chosen timer is per-CPU, behavior of other options slightly differs. kern.eventtimer.periodic - allows to choose periodic and one-shot operation mode. In periodic mode, current timer hardware taken as the only source of time for time events. This mode is quite alike to previous kernel behavior. One-shot mode instead uses currently selected time counter hardware to schedule all needed events one by one and program timer to generate interrupt exactly in specified time. Default value depends of chosen timer capabilities, but one-shot mode is preferred, until other is forced by user or hardware. kern.eventtimer.singlemul - in periodic mode specifies how much times higher timer frequency should be, to not strictly alias hardclock() and statclock() events. Default values are 2 and 4, but could be reduced to 1 if extra interrupts are unwanted. kern.eventtimer.idletick - makes each CPU to receive every timer interrupt independently of whether they busy or not. By default this options is disabled. If chosen timer is per-CPU and runs in periodic mode, this option has no effect - all interrupts are generating. As soon as this patch modifies cpu_idle() on some platforms, I have also refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions (if supported) under high sleep/wakeup rate, as fast alternative to other methods. It allows SMP scheduler to wake up sleeping CPUs much faster without using IPI, significantly increasing performance on some highly task-switching loads. Tested by: many (on i386, amd64, sparc64 and powerc) H/W donated by: Gheorghe Ardelean Sponsored by: iXsystems, Inc.
2010-09-13 07:25:35 +00:00
void
cpu_tick_calibration(void)
{
static time_t last_calib;
if (time_uptime != last_calib && !(time_uptime & 0xf)) {
cpu_tick_calibrate(0);
last_calib = time_uptime;
}
}
/*
2008-02-17 02:46:54 +00:00
* This function gets called every 16 seconds on only one designated
Refactor timer management code with priority to one-shot operation mode. The main goal of this is to generate timer interrupts only when there is some work to do. When CPU is busy interrupts are generating at full rate of hz + stathz to fullfill scheduler and timekeeping requirements. But when CPU is idle, only minimum set of interrupts (down to 8 interrupts per second per CPU now), needed to handle scheduled callouts is executed. This allows significantly increase idle CPU sleep time, increasing effect of static power-saving technologies. Also it should reduce host CPU load on virtualized systems, when guest system is idle. There is set of tunables, also available as writable sysctls, allowing to control wanted event timer subsystem behavior: kern.eventtimer.timer - allows to choose event timer hardware to use. On x86 there is up to 4 different kinds of timers. Depending on whether chosen timer is per-CPU, behavior of other options slightly differs. kern.eventtimer.periodic - allows to choose periodic and one-shot operation mode. In periodic mode, current timer hardware taken as the only source of time for time events. This mode is quite alike to previous kernel behavior. One-shot mode instead uses currently selected time counter hardware to schedule all needed events one by one and program timer to generate interrupt exactly in specified time. Default value depends of chosen timer capabilities, but one-shot mode is preferred, until other is forced by user or hardware. kern.eventtimer.singlemul - in periodic mode specifies how much times higher timer frequency should be, to not strictly alias hardclock() and statclock() events. Default values are 2 and 4, but could be reduced to 1 if extra interrupts are unwanted. kern.eventtimer.idletick - makes each CPU to receive every timer interrupt independently of whether they busy or not. By default this options is disabled. If chosen timer is per-CPU and runs in periodic mode, this option has no effect - all interrupts are generating. As soon as this patch modifies cpu_idle() on some platforms, I have also refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions (if supported) under high sleep/wakeup rate, as fast alternative to other methods. It allows SMP scheduler to wake up sleeping CPUs much faster without using IPI, significantly increasing performance on some highly task-switching loads. Tested by: many (on i386, amd64, sparc64 and powerc) H/W donated by: Gheorghe Ardelean Sponsored by: iXsystems, Inc.
2010-09-13 07:25:35 +00:00
* CPU in the system from hardclock() via cpu_tick_calibration()().
*
* Whenever the real time clock is stepped we get called with reset=1
* to make sure we handle suspend/resume and similar events correctly.
*/
static void
cpu_tick_calibrate(int reset)
{
static uint64_t c_last;
uint64_t c_this, c_delta;
static struct bintime t_last;
struct bintime t_this, t_delta;
uint32_t divi;
if (reset) {
/* The clock was stepped, abort & reset */
t_last.sec = 0;
return;
}
/* we don't calibrate fixed rate cputicks */
if (!cpu_tick_variable)
return;
getbinuptime(&t_this);
c_this = cpu_ticks();
if (t_last.sec != 0) {
c_delta = c_this - c_last;
t_delta = t_this;
bintime_sub(&t_delta, &t_last);
/*
* Headroom:
* 2^(64-20) / 16[s] =
* 2^(44) / 16[s] =
* 17.592.186.044.416 / 16 =
* 1.099.511.627.776 [Hz]
*/
divi = t_delta.sec << 20;
divi |= t_delta.frac >> (64 - 20);
c_delta <<= 20;
c_delta /= divi;
if (c_delta > cpu_tick_frequency) {
if (0 && bootverbose)
printf("cpu_tick increased to %ju Hz\n",
c_delta);
cpu_tick_frequency = c_delta;
}
}
c_last = c_this;
t_last = t_this;
}
void
set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
{
if (func == NULL) {
cpu_ticks = tc_cpu_ticks;
} else {
cpu_tick_frequency = freq;
cpu_tick_variable = var;
cpu_ticks = func;
}
}
uint64_t
cpu_tickrate(void)
{
if (cpu_ticks == tc_cpu_ticks)
return (tc_getfrequency());
return (cpu_tick_frequency);
}
/*
* We need to be slightly careful converting cputicks to microseconds.
* There is plenty of margin in 64 bits of microseconds (half a million
* years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
* before divide conversion (to retain precision) we find that the
* margin shrinks to 1.5 hours (one millionth of 146y).
* With a three prong approach we never lose significant bits, no
* matter what the cputick rate and length of timeinterval is.
*/
uint64_t
cputick2usec(uint64_t tick)
{
if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */
return (tick / (cpu_tickrate() / 1000000LL));
else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */
return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
else
return ((tick * 1000000LL) / cpu_tickrate());
}
cpu_tick_f *cpu_ticks = tc_cpu_ticks;
static int vdso_th_enable = 1;
static int
sysctl_fast_gettime(SYSCTL_HANDLER_ARGS)
{
int old_vdso_th_enable, error;
old_vdso_th_enable = vdso_th_enable;
error = sysctl_handle_int(oidp, &old_vdso_th_enable, 0, req);
if (error != 0)
return (error);
vdso_th_enable = old_vdso_th_enable;
timekeep_push_vdso();
return (0);
}
SYSCTL_PROC(_kern_timecounter, OID_AUTO, fast_gettime,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
NULL, 0, sysctl_fast_gettime, "I", "Enable fast time of day");
uint32_t
tc_fill_vdso_timehands(struct vdso_timehands *vdso_th)
{
struct timehands *th;
uint32_t enabled;
th = timehands;
vdso_th->th_algo = VDSO_TH_ALGO_1;
vdso_th->th_scale = th->th_scale;
vdso_th->th_offset_count = th->th_offset_count;
vdso_th->th_counter_mask = th->th_counter->tc_counter_mask;
vdso_th->th_offset = th->th_offset;
vdso_th->th_boottime = boottimebin;
enabled = cpu_fill_vdso_timehands(vdso_th);
if (!vdso_th_enable)
enabled = 0;
return (enabled);
}
#ifdef COMPAT_FREEBSD32
uint32_t
tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32)
{
struct timehands *th;
uint32_t enabled;
th = timehands;
vdso_th32->th_algo = VDSO_TH_ALGO_1;
*(uint64_t *)&vdso_th32->th_scale[0] = th->th_scale;
vdso_th32->th_offset_count = th->th_offset_count;
vdso_th32->th_counter_mask = th->th_counter->tc_counter_mask;
vdso_th32->th_offset.sec = th->th_offset.sec;
*(uint64_t *)&vdso_th32->th_offset.frac[0] = th->th_offset.frac;
vdso_th32->th_boottime.sec = boottimebin.sec;
*(uint64_t *)&vdso_th32->th_boottime.frac[0] = boottimebin.frac;
enabled = cpu_fill_vdso_timehands32(vdso_th32);
if (!vdso_th_enable)
enabled = 0;
return (enabled);
}
#endif