initial import of NetBSD tree

1 files changed, 581 insertions, 0 deletions

diff --git a/sys/kern/kern_clock.c b/sys/kern/kern_clock.c
new file mode 100644
index 00000000000..75118472993
--- /dev/null
+++ b/sys/kern/kern_clock.c
@@ -0,0 +1,581 @@
+/*	$NetBSD: kern_clock.c,v 1.22 1995/03/03 01:24:03 cgd Exp $	*/
+
+/*-
+ * 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
+ */
+
+#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 <machine/cpu.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.)
+ */
+
+/*
+ * 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;
+int	profprocs;
+int	ticks;
+static int psdiv, pscnt;		/* prof => stat divider */
+int	psratio;			/* ratio: prof / stat */
+int	tickfix, tickfixinterval;	/* used if tick not really integral */
+static int tickfixcnt;			/* number of ticks since last fix */
+
+volatile struct	timeval time;
+volatile struct	timeval mono_time;
+
+/*
+ * Initialize clock frequencies and start both clocks running.
+ */
+void
+initclocks()
+{
+	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 callout *p1;
+	register struct proc *p;
+	register int delta, needsoft;
+	extern int tickdelta;
+	extern long timedelta;
+
+	/*
+	 * Update real-time timeout queue.
+	 * At front of queue are some number of events which are ``due''.
+	 * The time to these is <= 0 and if negative represents the
+	 * number of ticks which have passed since it was supposed to happen.
+	 * The rest of the q elements (times > 0) are events yet to happen,
+	 * where the time for each is given as a delta from the previous.
+	 * Decrementing just the first of these serves to decrement the time
+	 * to all events.
+	 */
+	needsoft = 0;
+	for (p1 = calltodo.c_next; p1 != NULL; p1 = p1->c_next) {
+		if (--p1->c_time > 0)
+			break;
+		needsoft = 1;
+		if (p1->c_time == 0)
+			break;
+	}
+
+	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 no separate statistics clock is available, run it from here.
+	 */
+	if (stathz == 0)
+		statclock(frame);
+
+	/*
+	 * Increment the time-of-day.  The increment is normally just
+	 * ``tick''.  If the machine is one which has a clock frequency
+	 * such that ``hz'' would not divide the second evenly into
+	 * milliseconds, a periodic adjustment must be applied.  Finally,
+	 * if we are still adjusting the time (see adjtime()),
+	 * ``tickdelta'' may also be added in.
+	 */
+	ticks++;
+	delta = tick;
+	if (tickfix) {
+		tickfixcnt++;
+		if (tickfixcnt > tickfixinterval) {
+			delta += tickfix;
+			tickfixcnt = 0;
+		}
+	}
+	if (timedelta != 0) {
+		delta = tick + tickdelta;
+		timedelta -= tickdelta;
+	}
+	BUMPTIME(&time, delta);
+	BUMPTIME(&mono_time, delta);
+
+	/*
+	 * Process callouts at a very low cpu priority, so we don't keep the
+	 * relatively high clock interrupt priority any longer than necessary.
+	 */
+	if (needsoft) {
+		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();
+	}
+}
+
+/*
+ * Software (low priority) clock interrupt.
+ * Run periodic events from timeout queue.
+ */
+/*ARGSUSED*/
+void
+softclock()
+{
+	register struct callout *c;
+	register void *arg;
+	register void (*func) __P((void *));
+	register int s;
+
+	s = splhigh();
+	while ((c = calltodo.c_next) != NULL && c->c_time <= 0) {
+		func = c->c_func;
+		arg = c->c_arg;
+		calltodo.c_next = c->c_next;
+		c->c_next = callfree;
+		callfree = c;
+		splx(s);
+		(*func)(arg);
+		(void) splhigh();
+	}
+	splx(s);
+}
+
+/*
+ * timeout --
+ *	Execute a function after a specified length of time.
+ *
+ * untimeout --
+ *	Cancel previous timeout function call.
+ *
+ *	See AT&T BCI Driver Reference Manual for specification.  This
+ *	implementation differs from that one in that no identification
+ *	value is returned from timeout, rather, the original arguments
+ *	to timeout are used to identify entries for untimeout.
+ */
+void
+timeout(ftn, arg, ticks)
+	void (*ftn) __P((void *));
+	void *arg;
+	register int ticks;
+{
+	register struct callout *new, *p, *t;
+	register int s;
+
+	if (ticks <= 0)
+		ticks = 1;
+
+	/* Lock out the clock. */
+	s = splhigh();
+
+	/* Fill in the next free callout structure. */
+	if (callfree == NULL)
+		panic("timeout table full");
+	new = callfree;
+	callfree = new->c_next;
+	new->c_arg = arg;
+	new->c_func = ftn;
+
+	/*
+	 * The time for each event is stored as a difference from the time
+	 * of the previous event on the queue.  Walk the queue, correcting
+	 * the ticks argument for queue entries passed.  Correct the ticks
+	 * value for the queue entry immediately after the insertion point
+	 * as well.  Watch out for negative c_time values; these represent
+	 * overdue events.
+	 */
+	for (p = &calltodo;
+	    (t = p->c_next) != NULL && ticks > t->c_time; p = t)
+		if (t->c_time > 0)
+			ticks -= t->c_time;
+	new->c_time = ticks;
+	if (t != NULL)
+		t->c_time -= ticks;
+
+	/* Insert the new entry into the queue. */
+	p->c_next = new;
+	new->c_next = t;
+	splx(s);
+}
+
+void
+untimeout(ftn, arg)
+	void (*ftn) __P((void *));
+	void *arg;
+{
+	register struct callout *p, *t;
+	register int s;
+
+	s = splhigh();
+	for (p = &calltodo; (t = p->c_next) != NULL; p = t)
+		if (t->c_func == ftn && t->c_arg == arg) {
+			/* Increment next entry's tick count. */
+			if (t->c_next && t->c_time > 0)
+				t->c_next->c_time += t->c_time;
+
+			/* Move entry from callout queue to callfree queue. */
+			p->c_next = t->c_next;
+			t->c_next = callfree;
+			callfree = t;
+			break;
+		}
+	splx(s);
+}
+
+/*
+ * 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 long ticks, sec;
+	int s;
+
+	/*
+	 * If number of microseconds will fit in 32 bit arithmetic,
+	 * then compute number of microseconds to time and scale to
+	 * ticks.  Otherwise just compute number of hz in time, rounding
+	 * times greater than representible to maximum value.  (We must
+	 * compute in microseconds, because hz can be greater than 1000,
+	 * and thus tick can be less than one millisecond).
+	 *
+	 * Delta times less than 14 hours can be computed ``exactly''.
+	 * (Note that if hz would yeild a non-integral number of us per
+	 * tick, i.e. tickfix is nonzero, timouts can be a tick longer
+	 * than they should be.)  Maximum value for any timeout in 10ms
+	 * ticks is 250 days.
+	 */
+	s = splhigh();
+	sec = tv->tv_sec - time.tv_sec;
+	if (sec <= 0x7fffffff / 1000000 - 1)
+		ticks = ((tv->tv_sec - time.tv_sec) * 1000000 +
+			(tv->tv_usec - time.tv_usec)) / tick;
+	else if (sec <= 0x7fffffff / hz)
+		ticks = sec * hz;
+	else
+		ticks = 0x7fffffff;
+	splx(s);
+	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);
+		}
+	}
+}
+
+int	dk_ndrive = DK_NDRIVE;
+
+/*
+ * 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;
+	register int i;
+
+	if (CLKF_USERMODE(frame)) {
+		p = curproc;
+		if (p->p_flag & P_PROFIL)
+			addupc_intr(p, CLKF_PC(frame), 1);
+		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 (--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, 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;
+		}
+	}
+}
+
+/*
+ * Return information about system clocks.
+ */
+sysctl_clockrate(where, sizep)
+	register char *where;
+	size_t *sizep;
+{
+	struct clockinfo clkinfo;
+
+	/*
+	 * Construct clockinfo structure.
+	 */
+	clkinfo.tick = tick;
+	clkinfo.tickadj = tickadj;
+	clkinfo.hz = hz;
+	clkinfo.profhz = profhz;
+	clkinfo.stathz = stathz ? stathz : hz;
+	return (sysctl_rdstruct(where, sizep, NULL, &clkinfo, sizeof(clkinfo)));
+}
+
+#ifdef DDB
+#include <machine/db_machdep.h>
+
+#include <ddb/db_access.h>
+#include <ddb/db_sym.h>
+
+void db_show_callout(long addr, int haddr, int count, char *modif)
+{
+	register struct callout *p1;
+	register int	cum;
+	register int	s;
+	db_expr_t	offset;
+	char		*name;
+
+        db_printf("      cum     ticks      arg  func\n");
+	s = splhigh();
+	for (cum = 0, p1 = calltodo.c_next; p1; p1 = p1->c_next) {
+		register int t = p1->c_time;
+
+		if (t > 0)
+			cum += t;
+
+		db_find_sym_and_offset((db_addr_t)p1->c_func, &name, &offset);
+		if (name == NULL)
+			name = "?";
+
+                db_printf("%9d %9d %8x  %s (%x)\n",
+			  cum, t, p1->c_arg, name, p1->c_func);
+	}
+	splx(s);
+}
+#endif