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6b6ef746e5
freebsd-dev/sys/kern/kern_tc.c
Bruce Evans 6b6ef746e5 Added a sysctl "kern.timecounter.hardware" for selecting the hardware 
used for timecounting.  The possible values are the names of the
physically present harware timecounters ("i8254" and "TSC" on i386's).

Fixed some nearby bitrot in comments in <sys/time.h>.

Reviewed by:	phk
1999-07-18 15:07:20 +00:00

997 lines
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/*-
* Copyright (c) 1997, 1998 Poul-Henning Kamp <phk@FreeBSD.org>
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
* $Id: kern_clock.c,v 1.95 1999/07/18 01:35:26 jdp Exp $
*/
#include "opt_ntp.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dkstat.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/timex.h>
#include <sys/timepps.h>
#include <vm/vm.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/sysctl.h>
#include <machine/cpu.h>
#include <machine/limits.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
#if defined(SMP) && defined(BETTER_CLOCK)
#include <machine/smp.h>
#endif
/*
* Number of timecounters used to implement stable storage
*/
#ifndef NTIMECOUNTER
#define NTIMECOUNTER 5
#endif
static MALLOC_DEFINE(M_TIMECOUNTER, "timecounter",
"Timecounter stable storage");
static void initclocks __P((void *dummy));
SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
static void tco_forward __P((int force));
static void tco_setscales __P((struct timecounter *tc));
static __inline unsigned tco_delta __P((struct timecounter *tc));
/* Some of these don't belong here, but it's easiest to concentrate them. */
#if defined(SMP) && defined(BETTER_CLOCK)
long cp_time[CPUSTATES];
#else
static long cp_time[CPUSTATES];
#endif
long tk_cancc;
long tk_nin;
long tk_nout;
long tk_rawcc;
time_t time_second;
/*
* Which update policy to use.
* 0 - every tick, bad hardware may fail with "calcru negative..."
* 1 - more resistent to the above hardware, but less efficient.
*/
static int tco_method;
/*
* 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
* timeservices.
*/
static unsigned
dummy_get_timecount(struct timecounter *tc)
{
static unsigned now;
return (++now);
}
static struct timecounter dummy_timecounter = {
dummy_get_timecount,
0,
~0u,
1000000,
"dummy"
};
struct timecounter *timecounter = &dummy_timecounter;
/*
* Clock handling routines.
*
* This code is written to operate with two timers that run independently of
* each other.
*
* The main timer, running hz times per second, is used to trigger interval
* timers, timeouts and rescheduling as needed.
*
* The second timer handles kernel and user profiling,
* and does resource use estimation. If the second timer is programmable,
* it is randomized to avoid aliasing between the two clocks. For example,
* the randomization prevents an adversary from always giving up the cpu
* just before its quantum expires. Otherwise, it would never accumulate
* cpu ticks. The mean frequency of the second timer is stathz.
*
* If no second timer exists, stathz will be zero; in this case we drive
* profiling and statistics off the main clock. This WILL NOT be accurate;
* do not do it unless absolutely necessary.
*
* The statistics clock may (or may not) be run at a higher rate while
* profiling. This profile clock runs at profhz. We require that profhz
* be an integral multiple of stathz.
*
* If the statistics clock is running fast, it must be divided by the ratio
* profhz/stathz for statistics. (For profiling, every tick counts.)
*
* Time-of-day is maintained using a "timecounter", which may or may
* not be related to the hardware generating the above mentioned
* interrupts.
*/
int stathz;
int profhz;
static int profprocs;
int ticks;
static int psdiv, pscnt; /* prof => stat divider */
int psratio; /* ratio: prof / stat */
/*
* Initialize clock frequencies and start both clocks running.
*/
/* ARGSUSED*/
static void
initclocks(dummy)
void *dummy;
{
register int i;
/*
* Set divisors to 1 (normal case) and let the machine-specific
* code do its bit.
*/
psdiv = pscnt = 1;
cpu_initclocks();
/*
* Compute profhz/stathz, and fix profhz if needed.
*/
i = stathz ? stathz : hz;
if (profhz == 0)
profhz = i;
psratio = profhz / i;
}
/*
* The real-time timer, interrupting hz times per second.
*/
void
hardclock(frame)
register struct clockframe *frame;
{
register struct proc *p;
p = curproc;
if (p) {
register struct pstats *pstats;
/*
* Run current process's virtual and profile time, as needed.
*/
pstats = p->p_stats;
if (CLKF_USERMODE(frame) &&
timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
psignal(p, SIGVTALRM);
if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
psignal(p, SIGPROF);
}
#if defined(SMP) && defined(BETTER_CLOCK)
forward_hardclock(pscnt);
#endif
/*
* If no separate statistics clock is available, run it from here.
*/
if (stathz == 0)
statclock(frame);
tco_forward(0);
ticks++;
/*
* Process callouts at a very low cpu priority, so we don't keep the
* relatively high clock interrupt priority any longer than necessary.
*/
if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) {
if (CLKF_BASEPRI(frame)) {
/*
* Save the overhead of a software interrupt;
* it will happen as soon as we return, so do it now.
*/
(void)splsoftclock();
softclock();
} else
setsoftclock();
} else if (softticks + 1 == ticks)
++softticks;
}
/*
* Compute number of ticks in the specified amount of time.
*/
int
tvtohz(tv)
struct timeval *tv;
{
register unsigned long ticks;
register long sec, usec;
/*
* If the number of usecs in the whole seconds part of the time
* difference fits in a long, then the total number of usecs will
* fit in an unsigned long. Compute the total and convert it to
* ticks, rounding up and adding 1 to allow for the current tick
* to expire. Rounding also depends on unsigned long arithmetic
* to avoid overflow.
*
* Otherwise, if the number of ticks in the whole seconds part of
* the time difference fits in a long, then convert the parts to
* ticks separately and add, using similar rounding methods and
* overflow avoidance. This method would work in the previous
* case but it is slightly slower and assumes that hz is integral.
*
* Otherwise, round the time difference down to the maximum
* representable value.
*
* If ints have 32 bits, then the maximum value for any timeout in
* 10ms ticks is 248 days.
*/
sec = tv->tv_sec;
usec = tv->tv_usec;
if (usec < 0) {
sec--;
usec += 1000000;
}
if (sec < 0) {
#ifdef DIAGNOSTIC
if (usec > 0) {
sec++;
usec -= 1000000;
}
printf("tvotohz: negative time difference %ld sec %ld usec\n",
sec, usec);
#endif
ticks = 1;
} else if (sec <= LONG_MAX / 1000000)
ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
/ tick + 1;
else if (sec <= LONG_MAX / hz)
ticks = sec * hz
+ ((unsigned long)usec + (tick - 1)) / tick + 1;
else
ticks = LONG_MAX;
if (ticks > INT_MAX)
ticks = INT_MAX;
return ((int)ticks);
}
/*
* Start profiling on a process.
*
* Kernel profiling passes proc0 which never exits and hence
* keeps the profile clock running constantly.
*/
void
startprofclock(p)
register struct proc *p;
{
int s;
if ((p->p_flag & P_PROFIL) == 0) {
p->p_flag |= P_PROFIL;
if (++profprocs == 1 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = psratio;
setstatclockrate(profhz);
splx(s);
}
}
}
/*
* Stop profiling on a process.
*/
void
stopprofclock(p)
register struct proc *p;
{
int s;
if (p->p_flag & P_PROFIL) {
p->p_flag &= ~P_PROFIL;
if (--profprocs == 0 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = 1;
setstatclockrate(stathz);
splx(s);
}
}
}
/*
* Statistics clock. Grab profile sample, and if divider reaches 0,
* do process and kernel statistics.
*/
void
statclock(frame)
register struct clockframe *frame;
{
#ifdef GPROF
register struct gmonparam *g;
int i;
#endif
register struct proc *p;
struct pstats *pstats;
long rss;
struct rusage *ru;
struct vmspace *vm;
if (curproc != NULL && CLKF_USERMODE(frame)) {
p = curproc;
if (p->p_flag & P_PROFIL)
addupc_intr(p, CLKF_PC(frame), 1);
#if defined(SMP) && defined(BETTER_CLOCK)
if (stathz != 0)
forward_statclock(pscnt);
#endif
if (--pscnt > 0)
return;
/*
* Came from user mode; CPU was in user state.
* If this process is being profiled record the tick.
*/
p->p_uticks++;
if (p->p_nice > NZERO)
cp_time[CP_NICE]++;
else
cp_time[CP_USER]++;
} else {
#ifdef GPROF
/*
* Kernel statistics are just like addupc_intr, only easier.
*/
g = &_gmonparam;
if (g->state == GMON_PROF_ON) {
i = CLKF_PC(frame) - g->lowpc;
if (i < g->textsize) {
i /= HISTFRACTION * sizeof(*g->kcount);
g->kcount[i]++;
}
}
#endif
#if defined(SMP) && defined(BETTER_CLOCK)
if (stathz != 0)
forward_statclock(pscnt);
#endif
if (--pscnt > 0)
return;
/*
* Came from kernel mode, so we were:
* - handling an interrupt,
* - doing syscall or trap work on behalf of the current
* user process, or
* - spinning in the idle loop.
* Whichever it is, charge the time as appropriate.
* Note that we charge interrupts to the current process,
* regardless of whether they are ``for'' that process,
* so that we know how much of its real time was spent
* in ``non-process'' (i.e., interrupt) work.
*/
p = curproc;
if (CLKF_INTR(frame)) {
if (p != NULL)
p->p_iticks++;
cp_time[CP_INTR]++;
} else if (p != NULL) {
p->p_sticks++;
cp_time[CP_SYS]++;
} else
cp_time[CP_IDLE]++;
}
pscnt = psdiv;
/*
* We maintain statistics shown by user-level statistics
* programs: the amount of time in each cpu state.
*/
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (p_estcpu) is increased here. The formula for computing
* priorities (in kern_synch.c) will compute a different value each
* time p_estcpu increases by 4. The cpu usage estimator ramps up
* quite quickly when the process is running (linearly), and decays
* away exponentially, at a rate which is proportionally slower when
* the system is busy. The basic principal is that the system will
* 90% forget that the process used a lot of CPU time in 5 * loadav
* seconds. This causes the system to favor processes which haven't
* run much recently, and to round-robin among other processes.
*/
if (p != NULL) {
p->p_cpticks++;
if (++p->p_estcpu == 0)
p->p_estcpu--;
if ((p->p_estcpu & 3) == 0) {
resetpriority(p);
if (p->p_priority >= PUSER)
p->p_priority = p->p_usrpri;
}
/* Update resource usage integrals and maximums. */
if ((pstats = p->p_stats) != NULL &&
(ru = &pstats->p_ru) != NULL &&
(vm = p->p_vmspace) != NULL) {
ru->ru_ixrss += pgtok(vm->vm_tsize);
ru->ru_idrss += pgtok(vm->vm_dsize);
ru->ru_isrss += pgtok(vm->vm_ssize);
rss = pgtok(vmspace_resident_count(vm));
if (ru->ru_maxrss < rss)
ru->ru_maxrss = rss;
}
}
}
/*
* Return information about system clocks.
*/
static int
sysctl_kern_clockrate SYSCTL_HANDLER_ARGS
{
struct clockinfo clkinfo;
/*
* Construct clockinfo structure.
*/
clkinfo.hz = hz;
clkinfo.tick = tick;
clkinfo.tickadj = tickadj;
clkinfo.profhz = profhz;
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
}
SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
0, 0, sysctl_kern_clockrate, "S,clockinfo","");
static __inline unsigned
tco_delta(struct timecounter *tc)
{
return ((tc->tc_get_timecount(tc) - tc->tc_offset_count) &
tc->tc_counter_mask);
}
/*
* We have eight functions for looking at the clock, four for
* microseconds and four for nanoseconds. For each there is fast
* but less precise version "get{nano|micro}[up]time" which will
* return a time which is up to 1/HZ previous to the call, whereas
* the raw version "{nano|micro}[up]time" will return a timestamp
* which is as precise as possible. The "up" variants return the
* time relative to system boot, these are well suited for time
* interval measurements.
*/
void
getmicrotime(struct timeval *tvp)
{
struct timecounter *tc;
if (!tco_method) {
tc = timecounter;
*tvp = tc->tc_microtime;
} else {
microtime(tvp);
}
}
void
getnanotime(struct timespec *tsp)
{
struct timecounter *tc;
if (!tco_method) {
tc = timecounter;
*tsp = tc->tc_nanotime;
} else {
nanotime(tsp);
}
}
void
microtime(struct timeval *tv)
{
struct timecounter *tc;
tc = timecounter;
tv->tv_sec = tc->tc_offset_sec;
tv->tv_usec = tc->tc_offset_micro;
tv->tv_usec += ((u_int64_t)tco_delta(tc) * tc->tc_scale_micro) >> 32;
tv->tv_usec += boottime.tv_usec;
tv->tv_sec += boottime.tv_sec;
while (tv->tv_usec >= 1000000) {
tv->tv_usec -= 1000000;
tv->tv_sec++;
}
}
void
nanotime(struct timespec *ts)
{
unsigned count;
u_int64_t delta;
struct timecounter *tc;
tc = timecounter;
ts->tv_sec = tc->tc_offset_sec;
count = tco_delta(tc);
delta = tc->tc_offset_nano;
delta += ((u_int64_t)count * tc->tc_scale_nano_f);
delta >>= 32;
delta += ((u_int64_t)count * tc->tc_scale_nano_i);
delta += boottime.tv_usec * 1000;
ts->tv_sec += boottime.tv_sec;
while (delta >= 1000000000) {
delta -= 1000000000;
ts->tv_sec++;
}
ts->tv_nsec = delta;
}
void
getmicrouptime(struct timeval *tvp)
{
struct timecounter *tc;
if (!tco_method) {
tc = timecounter;
tvp->tv_sec = tc->tc_offset_sec;
tvp->tv_usec = tc->tc_offset_micro;
} else {
microuptime(tvp);
}
}
void
getnanouptime(struct timespec *tsp)
{
struct timecounter *tc;
if (!tco_method) {
tc = timecounter;
tsp->tv_sec = tc->tc_offset_sec;
tsp->tv_nsec = tc->tc_offset_nano >> 32;
} else {
nanouptime(tsp);
}
}
void
microuptime(struct timeval *tv)
{
struct timecounter *tc;
tc = timecounter;
tv->tv_sec = tc->tc_offset_sec;
tv->tv_usec = tc->tc_offset_micro;
tv->tv_usec += ((u_int64_t)tco_delta(tc) * tc->tc_scale_micro) >> 32;
if (tv->tv_usec >= 1000000) {
tv->tv_usec -= 1000000;
tv->tv_sec++;
}
}
void
nanouptime(struct timespec *ts)
{
unsigned count;
u_int64_t delta;
struct timecounter *tc;
tc = timecounter;
ts->tv_sec = tc->tc_offset_sec;
count = tco_delta(tc);
delta = tc->tc_offset_nano;
delta += ((u_int64_t)count * tc->tc_scale_nano_f);
delta >>= 32;
delta += ((u_int64_t)count * tc->tc_scale_nano_i);
if (delta >= 1000000000) {
delta -= 1000000000;
ts->tv_sec++;
}
ts->tv_nsec = delta;
}
static void
tco_setscales(struct timecounter *tc)
{
u_int64_t scale;
scale = 1000000000LL << 32;
scale += tc->tc_adjustment;
scale /= tc->tc_tweak->tc_frequency;
tc->tc_scale_micro = scale / 1000;
tc->tc_scale_nano_f = scale & 0xffffffff;
tc->tc_scale_nano_i = scale >> 32;
}
void
update_timecounter(struct timecounter *tc)
{
tco_setscales(tc);
}
void
init_timecounter(struct timecounter *tc)
{
struct timespec ts1;
struct timecounter *t1, *t2, *t3;
int i;
tc->tc_adjustment = 0;
tc->tc_tweak = tc;
tco_setscales(tc);
tc->tc_offset_count = tc->tc_get_timecount(tc);
if (timecounter == &dummy_timecounter)
tc->tc_avail = tc;
else {
tc->tc_avail = timecounter->tc_tweak->tc_avail;
timecounter->tc_tweak->tc_avail = tc;
}
MALLOC(t1, struct timecounter *, sizeof *t1, M_TIMECOUNTER, M_WAITOK);
tc->tc_other = t1;
*t1 = *tc;
t2 = t1;
for (i = 1; i < NTIMECOUNTER; i++) {
MALLOC(t3, struct timecounter *, sizeof *t3,
M_TIMECOUNTER, M_WAITOK);
*t3 = *tc;
t3->tc_other = t2;
t2 = t3;
}
t1->tc_other = t3;
tc = t1;
printf("Timecounter \"%s\" frequency %lu Hz\n",
tc->tc_name, (u_long)tc->tc_frequency);
/* XXX: For now always start using the counter. */
tc->tc_offset_count = tc->tc_get_timecount(tc);
nanouptime(&ts1);
tc->tc_offset_nano = (u_int64_t)ts1.tv_nsec << 32;
tc->tc_offset_micro = ts1.tv_nsec / 1000;
tc->tc_offset_sec = ts1.tv_sec;
timecounter = tc;
}
void
set_timecounter(struct timespec *ts)
{
struct timespec ts2;
nanouptime(&ts2);
boottime.tv_sec = ts->tv_sec - ts2.tv_sec;
boottime.tv_usec = (ts->tv_nsec - ts2.tv_nsec) / 1000;
if (boottime.tv_usec < 0) {
boottime.tv_usec += 1000000;
boottime.tv_sec--;
}
/* fiddle all the little crinkly bits around the fiords... */
tco_forward(1);
}
static void
switch_timecounter(struct timecounter *newtc)
{
int s;
struct timecounter *tc;
struct timespec ts;
s = splclock();
tc = timecounter;
if (newtc->tc_tweak == tc->tc_tweak) {
splx(s);
return;
}
newtc = newtc->tc_tweak->tc_other;
nanouptime(&ts);
newtc->tc_offset_sec = ts.tv_sec;
newtc->tc_offset_nano = (u_int64_t)ts.tv_nsec << 32;
newtc->tc_offset_micro = ts.tv_nsec / 1000;
newtc->tc_offset_count = newtc->tc_get_timecount(newtc);
tco_setscales(newtc);
timecounter = newtc;
splx(s);
}
static struct timecounter *
sync_other_counter(void)
{
struct timecounter *tc, *tcn, *tco;
unsigned delta;
tco = timecounter;
tc = tco->tc_other;
tcn = tc->tc_other;
*tc = *tco;
tc->tc_other = tcn;
delta = tco_delta(tc);
tc->tc_offset_count += delta;
tc->tc_offset_count &= tc->tc_counter_mask;
tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_f;
tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_i << 32;
return (tc);
}
static void
tco_forward(int force)
{
struct timecounter *tc, *tco;
tco = timecounter;
tc = sync_other_counter();
/*
* We may be inducing a tiny error here, the tc_poll_pps() may
* process a latched count which happens after the tco_delta()
* in sync_other_counter(), which would extend the previous
* counters parameters into the domain of this new one.
* Since the timewindow is very small for this, the error is
* going to be only a few weenieseconds (as Dave Mills would
* say), so lets just not talk more about it, OK ?
*/
if (tco->tc_poll_pps)
tco->tc_poll_pps(tco);
if (timedelta != 0) {
tc->tc_offset_nano += (u_int64_t)(tickdelta * 1000) << 32;
timedelta -= tickdelta;
force++;
}
while (tc->tc_offset_nano >= 1000000000ULL << 32) {
tc->tc_offset_nano -= 1000000000ULL << 32;
tc->tc_offset_sec++;
ntp_update_second(tc); /* XXX only needed if xntpd runs */
tco_setscales(tc);
force++;
}
if (tco_method && !force)
return;
tc->tc_offset_micro = (tc->tc_offset_nano / 1000) >> 32;
/* Figure out the wall-clock time */
tc->tc_nanotime.tv_sec = tc->tc_offset_sec + boottime.tv_sec;
tc->tc_nanotime.tv_nsec =
(tc->tc_offset_nano >> 32) + boottime.tv_usec * 1000;
tc->tc_microtime.tv_usec = tc->tc_offset_micro + boottime.tv_usec;
if (tc->tc_nanotime.tv_nsec >= 1000000000) {
tc->tc_nanotime.tv_nsec -= 1000000000;
tc->tc_microtime.tv_usec -= 1000000;
tc->tc_nanotime.tv_sec++;
}
time_second = tc->tc_microtime.tv_sec = tc->tc_nanotime.tv_sec;
timecounter = tc;
}
SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
SYSCTL_INT(_kern_timecounter, OID_AUTO, method, CTLFLAG_RW, &tco_method, 0,
"This variable determines the method used for updating timecounters. "
"If the default algorithm (0) fails with \"calcru negative...\" messages "
"try the alternate algorithm (1) which handles bad hardware better."
);
static int
sysctl_kern_timecounter_hardware SYSCTL_HANDLER_ARGS
{
char newname[32];
struct timecounter *newtc, *tc;
int error;
tc = timecounter->tc_tweak;
strncpy(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) {
for (newtc = tc->tc_avail; newtc != tc; newtc = tc->tc_avail) {
if (strcmp(newname, newtc->tc_name) == 0) {
/* Warm up new timecounter. */
(void)newtc->tc_get_timecount(newtc);
switch_timecounter(newtc);
return (0);
}
}
return (EINVAL);
}
return (error);
}
SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
0, 0, sysctl_kern_timecounter_hardware, "A", "");
int
pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
{
pps_params_t *app;
pps_info_t *api;
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);
pps->ppsparam = *app;
return (0);
case PPS_IOC_GETPARAMS:
app = (pps_params_t *)data;
*app = pps->ppsparam;
return (0);
case PPS_IOC_GETCAP:
*(int*)data = pps->ppscap;
return (0);
case PPS_IOC_FETCH:
api = (pps_info_t *)data;
pps->ppsinfo.current_mode = pps->ppsparam.mode;
*api = pps->ppsinfo;
return (0);
case PPS_IOC_WAIT:
return (EOPNOTSUPP);
default:
return (ENOTTY);
}
}
void
pps_init(struct pps_state *pps)
{
pps->ppscap |= PPS_TSFMT_TSPEC;
if (pps->ppscap & PPS_CAPTUREASSERT)
pps->ppscap |= PPS_OFFSETASSERT;
if (pps->ppscap & PPS_CAPTURECLEAR)
pps->ppscap |= PPS_OFFSETCLEAR;
#ifdef PPS_SYNC
if (pps->ppscap & PPS_CAPTUREASSERT)
pps->ppscap |= PPS_HARDPPSONASSERT;
if (pps->ppscap & PPS_CAPTURECLEAR)
pps->ppscap |= PPS_HARDPPSONCLEAR;
#endif
}
void
pps_event(struct pps_state *pps, struct timecounter *tc, unsigned count, int event)
{
struct timespec ts, *tsp, *osp;
u_int64_t delta;
unsigned tcount, *pcount;
int foff, fhard;
pps_seq_t *pseq;
/* 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->ppsparam.mode & PPS_HARDPPSONASSERT;
pcount = &pps->ppscount[0];
pseq = &pps->ppsinfo.assert_sequence;
} else {
tsp = &pps->ppsinfo.clear_timestamp;
osp = &pps->ppsparam.clear_offset;
foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
fhard = pps->ppsparam.mode & PPS_HARDPPSONCLEAR;
pcount = &pps->ppscount[1];
pseq = &pps->ppsinfo.clear_sequence;
}
/* The timecounter changed: bail */
if (!pps->ppstc ||
pps->ppstc->tc_name != tc->tc_name ||
tc->tc_name != timecounter->tc_name) {
pps->ppstc = tc;
*pcount = count;
return;
}
/* Nothing really happened */
if (*pcount == count)
return;
*pcount = count;
/* Convert the count to timespec */
ts.tv_sec = tc->tc_offset_sec;
tcount = count - tc->tc_offset_count;
tcount &= tc->tc_counter_mask;
delta = tc->tc_offset_nano;
delta += ((u_int64_t)tcount * tc->tc_scale_nano_f);
delta >>= 32;
delta += ((u_int64_t)tcount * tc->tc_scale_nano_i);
delta += boottime.tv_usec * 1000;
ts.tv_sec += boottime.tv_sec;
while (delta >= 1000000000) {
delta -= 1000000000;
ts.tv_sec++;
}
ts.tv_nsec = delta;
(*pseq)++;
*tsp = ts;
if (foff) {
timespecadd(tsp, osp);
if (tsp->tv_nsec < 0) {
tsp->tv_nsec += 1000000000;
tsp->tv_sec -= 1;
}
}
#ifdef PPS_SYNC
if (fhard) {
/* magic, at its best... */
tcount = count - pps->ppscount[2];
pps->ppscount[2] = count;
tcount &= tc->tc_counter_mask;
delta = ((u_int64_t)tcount * tc->tc_tweak->tc_scale_nano_f);
delta >>= 32;
delta += ((u_int64_t)tcount * tc->tc_tweak->tc_scale_nano_i);
hardpps(tsp, delta);
}
#endif
}
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