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[netbsd-mini2440.git] / sys / kern / kern_clock.c

/*      $NetBSD: kern_clock.c,v 1.125 2008/07/02 19:38:37 rmind 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 1.125 2008/07/02 19:38:37 rmind 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);
        }
}