freebsd-dev/sys/kern/kern_clock.c

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1994-05-24 10:09:53 +00:00
/*-
* 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 1.52 1998/01/11 19:07:58 phk Exp $
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*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dkstat.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/timex.h>
#include <vm/vm.h>
#include <sys/lock.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <sys/sysctl.h>
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#include <machine/cpu.h>
#define CLOCK_HAIR /* XXX */
#include <machine/clock.h>
#include <machine/limits.h>
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#ifdef GPROF
#include <sys/gmon.h>
#endif
#if defined(SMP) && defined(BETTER_CLOCK)
#include <machine/smp.h>
#endif
static void initclocks __P((void *dummy));
SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
/* 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 dk_seek[DK_NDRIVE];
static long dk_time[DK_NDRIVE]; /* time busy (in statclock ticks) */
long dk_wds[DK_NDRIVE];
long dk_wpms[DK_NDRIVE];
long dk_xfer[DK_NDRIVE];
int dk_busy;
int dk_ndrive = 0;
char dk_names[DK_NDRIVE][DK_NAMELEN];
long tk_cancc;
long tk_nin;
long tk_nout;
long tk_rawcc;
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/*
* Clock handling routines.
*
* This code is written to operate with two timers that run independently of
* each other. The main clock, running hz times per second, is used to keep
* track of real time. The second timer handles kernel and user profiling,
* and does resource use estimation. If the second timer is programmable,
* it is randomized to avoid aliasing between the two clocks. For example,
* the randomization prevents an adversary from always giving up the cpu
* just before its quantum expires. Otherwise, it would never accumulate
* cpu ticks. The mean frequency of the second timer is stathz.
*
* If no second timer exists, stathz will be zero; in this case we drive
* profiling and statistics off the main clock. This WILL NOT be accurate;
* do not do it unless absolutely necessary.
*
* The statistics clock may (or may not) be run at a higher rate while
* profiling. This profile clock runs at profhz. We require that profhz
* be an integral multiple of stathz.
*
* If the statistics clock is running fast, it must be divided by the ratio
* profhz/stathz for statistics. (For profiling, every tick counts.)
*/
/*
* TODO:
* allocate more timeout table slots when table overflows.
*/
/*
* Bump a timeval by a small number of usec's.
*/
#define BUMPTIME(t, usec) { \
register volatile struct timeval *tp = (t); \
register long us; \
\
tp->tv_usec = us = tp->tv_usec + (usec); \
if (us >= 1000000) { \
tp->tv_usec = us - 1000000; \
tp->tv_sec++; \
} \
}
int stathz;
int profhz;
static int profprocs;
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int ticks;
init_main.c subr_autoconf.c: Add support for "interrupt driven configuration hooks". A component of the kernel can register a hook, most likely during auto-configuration, and receive a callback once interrupt services are available. This callback will occur before the root and dump devices are configured, so the configuration task can affect the selection of those two devices or complete any tasks that need to be performed prior to launching init. System boot is posponed so long as a hook is registered. The hook owner is responsible for removing the hook once their task is complete or the system boot can continue. kern_acct.c kern_clock.c kern_exit.c kern_synch.c kern_time.c: Change the interface and implementation for the kernel callout service. The new implemntaion is based on the work of Adam M. Costello and George Varghese, published in a technical report entitled "Redesigning the BSD Callout and Timer Facilities". The interface used in FreeBSD is a little different than the one outlined in the paper. The new function prototypes are: struct callout_handle timeout(void (*func)(void *), void *arg, int ticks); void untimeout(void (*func)(void *), void *arg, struct callout_handle handle); If a client wishes to remove a timeout, it must store the callout_handle returned by timeout and pass it to untimeout. The new implementation gives 0(1) insert and removal of callouts making this interface scale well even for applications that keep 100s of callouts outstanding. See the updated timeout.9 man page for more details.
1997-09-21 22:00:25 +00:00
static int psdiv, pscnt; /* prof => stat divider */
int psratio; /* ratio: prof / stat */
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volatile struct timeval time;
volatile struct timeval mono_time;
/*
* Initialize clock frequencies and start both clocks running.
*/
/* ARGSUSED*/
static void
initclocks(dummy)
void *dummy;
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{
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;
int time_update;
struct timeval newtime = time;
long ltemp;
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p = curproc;
if (p) {
register struct pstats *pstats;
/*
* Run current process's virtual and profile time, as needed.
*/
pstats = p->p_stats;
if (CLKF_USERMODE(frame) &&
timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
psignal(p, SIGVTALRM);
if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
psignal(p, SIGPROF);
}
#if defined(SMP) && defined(BETTER_CLOCK)
forward_hardclock(pscnt);
#endif
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/*
* If no separate statistics clock is available, run it from here.
*/
if (stathz == 0)
statclock(frame);
/*
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* Increment the time-of-day.
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*/
ticks++;
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if (timedelta == 0) {
time_update = CPU_THISTICKLEN(tick);
} else {
time_update = CPU_THISTICKLEN(tick) + tickdelta;
timedelta -= tickdelta;
}
BUMPTIME(&mono_time, time_update);
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/*
* 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;
}
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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.
*
* On a 32-bit machine and given parameters in the timex.h
* header file, the maximum phase adjustment is +-512 ms and
* maximum frequency offset is a tad less than) +-512 ppm. On a
* 64-bit machine, you shouldn't need to ask.
*/
if (newtime.tv_usec >= 1000000) {
newtime.tv_usec -= 1000000;
newtime.tv_sec++;
ntp_update_second(&newtime.tv_sec);
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}
CPU_CLOCKUPDATE(&time, &newtime);
if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL)
setsoftclock();
init_main.c subr_autoconf.c: Add support for "interrupt driven configuration hooks". A component of the kernel can register a hook, most likely during auto-configuration, and receive a callback once interrupt services are available. This callback will occur before the root and dump devices are configured, so the configuration task can affect the selection of those two devices or complete any tasks that need to be performed prior to launching init. System boot is posponed so long as a hook is registered. The hook owner is responsible for removing the hook once their task is complete or the system boot can continue. kern_acct.c kern_clock.c kern_exit.c kern_synch.c kern_time.c: Change the interface and implementation for the kernel callout service. The new implemntaion is based on the work of Adam M. Costello and George Varghese, published in a technical report entitled "Redesigning the BSD Callout and Timer Facilities". The interface used in FreeBSD is a little different than the one outlined in the paper. The new function prototypes are: struct callout_handle timeout(void (*func)(void *), void *arg, int ticks); void untimeout(void (*func)(void *), void *arg, struct callout_handle handle); If a client wishes to remove a timeout, it must store the callout_handle returned by timeout and pass it to untimeout. The new implementation gives 0(1) insert and removal of callouts making this interface scale well even for applications that keep 100s of callouts outstanding. See the updated timeout.9 man page for more details.
1997-09-21 22:00:25 +00:00
}
void
gettime(struct timeval *tvp)
{
int s;
s = splclock();
/* XXX should use microtime() iff tv_usec is used. */
*tvp = time;
splx(s);
}
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/*
* Compute number of hz until specified time. Used to
* compute third argument to timeout() from an absolute time.
*/
int
hzto(tv)
struct timeval *tv;
{
register unsigned long ticks;
register long sec, usec;
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int s;
/*
* If the number of usecs in the whole seconds part of the time
* difference fits in a long, then the total number of usecs will
* fit in an unsigned long. Compute the total and convert it to
* ticks, rounding up and adding 1 to allow for the current tick
* to expire. Rounding also depends on unsigned long arithmetic
* to avoid overflow.
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*
* 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.
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*/
s = splclock();
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sec = tv->tv_sec - time.tv_sec;
usec = tv->tv_usec - time.tv_usec;
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splx(s);
if (usec < 0) {
sec--;
usec += 1000000;
}
if (sec < 0) {
#ifdef DIAGNOSTIC
printf("hzto: negative time difference %ld sec %ld usec\n",
sec, usec);
#endif
ticks = 1;
} else if (sec <= LONG_MAX / 1000000)
ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
/ tick + 1;
else if (sec <= LONG_MAX / hz)
ticks = sec * hz
+ ((unsigned long)usec + (tick - 1)) / tick + 1;
else
ticks = LONG_MAX;
if (ticks > INT_MAX)
ticks = INT_MAX;
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return (ticks);
}
/*
* Start profiling on a process.
*
* Kernel profiling passes proc0 which never exits and hence
* keeps the profile clock running constantly.
*/
void
startprofclock(p)
register struct proc *p;
{
int s;
if ((p->p_flag & P_PROFIL) == 0) {
p->p_flag |= P_PROFIL;
if (++profprocs == 1 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = psratio;
setstatclockrate(profhz);
splx(s);
}
}
}
/*
* Stop profiling on a process.
*/
void
stopprofclock(p)
register struct proc *p;
{
int s;
if (p->p_flag & P_PROFIL) {
p->p_flag &= ~P_PROFIL;
if (--profprocs == 0 && stathz != 0) {
s = splstatclock();
psdiv = pscnt = 1;
setstatclockrate(stathz);
splx(s);
}
}
}
/*
* Statistics clock. Grab profile sample, and if divider reaches 0,
* do process and kernel statistics.
*/
void
statclock(frame)
register struct clockframe *frame;
{
#ifdef GPROF
register struct gmonparam *g;
#endif
register struct proc *p;
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register int i;
struct pstats *pstats;
long rss;
struct rusage *ru;
struct vmspace *vm;
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if (CLKF_USERMODE(frame)) {
p = curproc;
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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
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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);
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#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;
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if (CLKF_INTR(frame)) {
if (p != NULL)
p->p_iticks++;
cp_time[CP_INTR]++;
} else if (p != NULL) {
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p->p_sticks++;
cp_time[CP_SYS]++;
} else
cp_time[CP_IDLE]++;
}
pscnt = psdiv;
/*
* We maintain statistics shown by user-level statistics
* programs: the amount of time in each cpu state, and
* the amount of time each of DK_NDRIVE ``drives'' is busy.
*
* XXX should either run linked list of drives, or (better)
* grab timestamps in the start & done code.
*/
for (i = 0; i < DK_NDRIVE; i++)
if (dk_busy & (1 << i))
dk_time[i]++;
/*
* We adjust the priority of the current process. The priority of
* a process gets worse as it accumulates CPU time. The cpu usage
* estimator (p_estcpu) is increased here. The formula for computing
* priorities (in kern_synch.c) will compute a different value each
* time p_estcpu increases by 4. The cpu usage estimator ramps up
* quite quickly when the process is running (linearly), and decays
* away exponentially, at a rate which is proportionally slower when
* the system is busy. The basic principal is that the system will
* 90% forget that the process used a lot of CPU time in 5 * loadav
* seconds. This causes the system to favor processes which haven't
* run much recently, and to round-robin among other processes.
*/
if (p != NULL) {
p->p_cpticks++;
if (++p->p_estcpu == 0)
p->p_estcpu--;
if ((p->p_estcpu & 3) == 0) {
resetpriority(p);
if (p->p_priority >= PUSER)
p->p_priority = p->p_usrpri;
}
/* 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 += vm->vm_tsize * PAGE_SIZE / 1024;
ru->ru_idrss += vm->vm_dsize * PAGE_SIZE / 1024;
ru->ru_isrss += vm->vm_ssize * PAGE_SIZE / 1024;
rss = vm->vm_pmap.pm_stats.resident_count *
PAGE_SIZE / 1024;
if (ru->ru_maxrss < rss)
ru->ru_maxrss = rss;
}
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}
}
/*
* Return information about system clocks.
*/
static int
sysctl_kern_clockrate SYSCTL_HANDLER_ARGS
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{
struct clockinfo clkinfo;
/*
* Construct clockinfo structure.
*/
clkinfo.hz = hz;
clkinfo.tick = tick;
clkinfo.tickadj = tickadj;
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clkinfo.profhz = profhz;
clkinfo.stathz = stathz ? stathz : hz;
return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
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}
SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
0, 0, sysctl_kern_clockrate, "S,clockinfo","");