NetBSD/sys/kern/kern_clock.c

451 lines
12 KiB
C

/* $NetBSD: kern_clock.c,v 1.126 2008/10/05 21:57:20 pooka Exp $ */
/*-
* Copyright (c) 2000, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
* This code is derived from software contributed to The NetBSD Foundation
* by Charles M. Hannum.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
/*-
* 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. 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
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_clock.c,v 1.126 2008/10/05 21:57:20 pooka Exp $");
#include "opt_ntp.h"
#include "opt_perfctrs.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/callout.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/timex.h>
#include <sys/sched.h>
#include <sys/time.h>
#include <sys/timetc.h>
#include <sys/cpu.h>
#include <sys/atomic.h>
#include <uvm/uvm_extern.h>
#ifdef GPROF
#include <sys/gmon.h>
#endif
/*
* 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.)
*/
int stathz;
int profhz;
int profsrc;
int schedhz;
int profprocs;
int hardclock_ticks;
static int hardscheddiv; /* hard => sched divider (used if schedhz == 0) */
static int psdiv; /* prof => stat divider */
int psratio; /* ratio: prof / stat */
static u_int get_intr_timecount(struct timecounter *);
static struct timecounter intr_timecounter = {
get_intr_timecount, /* get_timecount */
0, /* no poll_pps */
~0u, /* counter_mask */
0, /* frequency */
"clockinterrupt", /* name */
0, /* quality - minimum implementation level for a clock */
NULL, /* prev */
NULL, /* next */
};
static u_int
get_intr_timecount(struct timecounter *tc)
{
return (u_int)hardclock_ticks;
}
/*
* Initialize clock frequencies and start both clocks running.
*/
void
initclocks(void)
{
int i;
/*
* Set divisors to 1 (normal case) and let the machine-specific
* code do its bit.
*/
psdiv = 1;
/*
* provide minimum default time counter
* will only run at interrupt resolution
*/
intr_timecounter.tc_frequency = hz;
tc_init(&intr_timecounter);
cpu_initclocks();
/*
* Compute profhz and stathz, fix profhz if needed.
*/
i = stathz ? stathz : hz;
if (profhz == 0)
profhz = i;
psratio = profhz / i;
if (schedhz == 0) {
/* 16Hz is best */
hardscheddiv = hz / 16;
if (hardscheddiv <= 0)
panic("hardscheddiv");
}
}
/*
* The real-time timer, interrupting hz times per second.
*/
void
hardclock(struct clockframe *frame)
{
struct lwp *l;
struct cpu_info *ci;
ci = curcpu();
l = ci->ci_data.cpu_onproc;
timer_tick(l, CLKF_USERMODE(frame));
/*
* If no separate statistics clock is available, run it from here.
*/
if (stathz == 0)
statclock(frame);
/*
* If no separate schedclock is provided, call it here
* at about 16 Hz.
*/
if (schedhz == 0) {
if ((int)(--ci->ci_schedstate.spc_schedticks) <= 0) {
schedclock(l);
ci->ci_schedstate.spc_schedticks = hardscheddiv;
}
}
if ((--ci->ci_schedstate.spc_ticks) <= 0)
sched_tick(ci);
if (CPU_IS_PRIMARY(ci)) {
hardclock_ticks++;
tc_ticktock();
}
/*
* Update real-time timeout queue.
*/
callout_hardclock();
}
/*
* Start profiling on a process.
*
* Kernel profiling passes proc0 which never exits and hence
* keeps the profile clock running constantly.
*/
void
startprofclock(struct proc *p)
{
KASSERT(mutex_owned(&p->p_stmutex));
if ((p->p_stflag & PST_PROFIL) == 0) {
p->p_stflag |= PST_PROFIL;
/*
* This is only necessary if using the clock as the
* profiling source.
*/
if (++profprocs == 1 && stathz != 0)
psdiv = psratio;
}
}
/*
* Stop profiling on a process.
*/
void
stopprofclock(struct proc *p)
{
KASSERT(mutex_owned(&p->p_stmutex));
if (p->p_stflag & PST_PROFIL) {
p->p_stflag &= ~PST_PROFIL;
/*
* This is only necessary if using the clock as the
* profiling source.
*/
if (--profprocs == 0 && stathz != 0)
psdiv = 1;
}
}
#if defined(PERFCTRS)
/*
* Independent profiling "tick" in case we're using a separate
* clock or profiling event source. Currently, that's just
* performance counters--hence the wrapper.
*/
void
proftick(struct clockframe *frame)
{
#ifdef GPROF
struct gmonparam *g;
intptr_t i;
#endif
struct lwp *l;
struct proc *p;
l = curcpu()->ci_data.cpu_onproc;
p = (l ? l->l_proc : NULL);
if (CLKF_USERMODE(frame)) {
mutex_spin_enter(&p->p_stmutex);
if (p->p_stflag & PST_PROFIL)
addupc_intr(l, CLKF_PC(frame));
mutex_spin_exit(&p->p_stmutex);
} else {
#ifdef GPROF
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
#ifdef LWP_PC
if (p != NULL && (p->p_stflag & PST_PROFIL) != 0)
addupc_intr(l, LWP_PC(l));
#endif
}
}
#endif
void
schedclock(struct lwp *l)
{
struct cpu_info *ci;
ci = l->l_cpu;
/* Accumulate syscall and context switch counts. */
atomic_add_int((unsigned *)&uvmexp.swtch, ci->ci_data.cpu_nswtch);
ci->ci_data.cpu_nswtch = 0;
atomic_add_int((unsigned *)&uvmexp.syscalls, ci->ci_data.cpu_nsyscall);
ci->ci_data.cpu_nsyscall = 0;
atomic_add_int((unsigned *)&uvmexp.traps, ci->ci_data.cpu_ntrap);
ci->ci_data.cpu_ntrap = 0;
if ((l->l_flag & LW_IDLE) != 0)
return;
sched_schedclock(l);
}
/*
* Statistics clock. Grab profile sample, and if divider reaches 0,
* do process and kernel statistics.
*/
void
statclock(struct clockframe *frame)
{
#ifdef GPROF
struct gmonparam *g;
intptr_t i;
#endif
struct cpu_info *ci = curcpu();
struct schedstate_percpu *spc = &ci->ci_schedstate;
struct proc *p;
struct lwp *l;
/*
* Notice changes in divisor frequency, and adjust clock
* frequency accordingly.
*/
if (spc->spc_psdiv != psdiv) {
spc->spc_psdiv = psdiv;
spc->spc_pscnt = psdiv;
if (psdiv == 1) {
setstatclockrate(stathz);
} else {
setstatclockrate(profhz);
}
}
l = ci->ci_data.cpu_onproc;
if ((l->l_flag & LW_IDLE) != 0) {
/*
* don't account idle lwps as swapper.
*/
p = NULL;
} else {
p = l->l_proc;
mutex_spin_enter(&p->p_stmutex);
}
if (CLKF_USERMODE(frame)) {
if ((p->p_stflag & PST_PROFIL) && profsrc == PROFSRC_CLOCK)
addupc_intr(l, CLKF_PC(frame));
if (--spc->spc_pscnt > 0) {
mutex_spin_exit(&p->p_stmutex);
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)
spc->spc_cp_time[CP_NICE]++;
else
spc->spc_cp_time[CP_USER]++;
} else {
#ifdef GPROF
/*
* Kernel statistics are just like addupc_intr, only easier.
*/
g = &_gmonparam;
if (profsrc == PROFSRC_CLOCK && g->state == GMON_PROF_ON) {
i = CLKF_PC(frame) - g->lowpc;
if (i < g->textsize) {
i /= HISTFRACTION * sizeof(*g->kcount);
g->kcount[i]++;
}
}
#endif
#ifdef LWP_PC
if (p != NULL && profsrc == PROFSRC_CLOCK &&
(p->p_stflag & PST_PROFIL)) {
addupc_intr(l, LWP_PC(l));
}
#endif
if (--spc->spc_pscnt > 0) {
if (p != NULL)
mutex_spin_exit(&p->p_stmutex);
return;
}
/*
* Came from kernel mode, so we were:
* - handling an interrupt,
* - doing syscall or trap work on behalf of the current
* user process, or
* - spinning in the idle loop.
* Whichever it is, charge the time as appropriate.
* Note that we charge interrupts to the current process,
* regardless of whether they are ``for'' that process,
* so that we know how much of its real time was spent
* in ``non-process'' (i.e., interrupt) work.
*/
if (CLKF_INTR(frame) || (curlwp->l_pflag & LP_INTR) != 0) {
if (p != NULL) {
p->p_iticks++;
}
spc->spc_cp_time[CP_INTR]++;
} else if (p != NULL) {
p->p_sticks++;
spc->spc_cp_time[CP_SYS]++;
} else {
spc->spc_cp_time[CP_IDLE]++;
}
}
spc->spc_pscnt = psdiv;
if (p != NULL) {
atomic_inc_uint(&l->l_cpticks);
mutex_spin_exit(&p->p_stmutex);
}
}