Initial source

1 files changed, 525 insertions, 0 deletions

diff --git a/kern/timer.c b/kern/timer.c
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+/* 
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
+ * All Rights Reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ * 
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ * 
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+
+#include <cpus.h>
+#include <stat_time.h>
+
+#include <mach/kern_return.h>
+#include <mach/port.h>
+#include <kern/queue.h>
+#include <kern/thread.h>
+#include <mach/time_value.h>
+#include <kern/timer.h>
+#include <kern/cpu_number.h>
+
+#include <kern/assert.h>
+#include <kern/macro_help.h>
+
+
+
+timer_t		current_timer[NCPUS];
+timer_data_t	kernel_timer[NCPUS];
+
+void timer_init(); /* forward */
+
+/*
+ *	init_timers initializes all non-thread timers and puts the
+ *	service routine on the callout queue.  All timers must be
+ *	serviced by the callout routine once an hour.
+ */
+void init_timers()
+{
+	register int	i;
+	register timer_t	this_timer;
+
+	/*
+	 *	Initialize all the kernel timers and start the one
+	 *	for this cpu (master) slaves start theirs later.
+	 */
+	this_timer = &kernel_timer[0];
+	for ( i=0 ; i<NCPUS ; i++, this_timer++) {
+		timer_init(this_timer);
+		current_timer[i] = (timer_t) 0;
+	}
+
+	start_timer(&kernel_timer[cpu_number()]);
+}
+
+/*
+ *	timer_init initializes a single timer.
+ */
+void timer_init(this_timer)
+register
+timer_t this_timer;
+{
+	this_timer->low_bits = 0;
+	this_timer->high_bits = 0;
+	this_timer->tstamp = 0;
+	this_timer->high_bits_check = 0;
+}
+
+#if	STAT_TIME
+#else	STAT_TIME
+
+#ifdef	MACHINE_TIMER_ROUTINES
+
+/*
+ *	Machine-dependent code implements the timer routines.
+ */
+
+#else	/* MACHINE_TIMER_ROUTINES */
+
+/*
+ *	start_timer starts the given timer for this cpu. It is called
+ *	exactly once for each cpu during the boot sequence.
+ */
+void
+start_timer(timer)
+timer_t timer;
+{
+	timer->tstamp = get_timestamp();
+	current_timer[cpu_number()] = timer;
+}
+
+/*
+ *	time_trap_uentry does trap entry timing.  Caller must lock out
+ *	interrupts and take a timestamp.  ts is a timestamp taken after
+ *	interrupts were locked out. Must only be called if trap was
+ *	from user mode.
+ */
+void
+time_trap_uentry(ts)
+unsigned ts;
+{
+	int	elapsed;
+	int	mycpu;
+	timer_t	mytimer;
+
+	/*
+	 *	Calculate elapsed time.
+	 */
+	mycpu = cpu_number();
+	mytimer = current_timer[mycpu];
+	elapsed = ts - mytimer->tstamp;
+#ifdef	TIMER_MAX
+	if (elapsed < 0) elapsed += TIMER_MAX;
+#endif	TIMER_MAX
+
+	/*
+	 *	Update current timer.
+	 */
+	mytimer->low_bits += elapsed;
+	mytimer->tstamp = 0;
+
+	if (mytimer->low_bits & TIMER_LOW_FULL) {
+		timer_normalize(mytimer);
+	}
+
+	/*
+	 *	Record new timer.
+	 */
+	mytimer = &(active_threads[mycpu]->system_timer);
+	current_timer[mycpu] = mytimer;
+	mytimer->tstamp = ts;
+}
+
+/*
+ *	time_trap_uexit does trap exit timing.  Caller must lock out
+ *	interrupts and take a timestamp.  ts is a timestamp taken after
+ *	interrupts were locked out.  Must only be called if returning to
+ *	user mode.
+ */
+void
+time_trap_uexit(ts)
+{
+	int	elapsed;
+	int	mycpu;
+	timer_t	mytimer;
+
+	/*
+	 *	Calculate elapsed time.
+	 */
+	mycpu = cpu_number();
+	mytimer = current_timer[mycpu];
+	elapsed = ts - mytimer->tstamp;
+#ifdef	TIMER_MAX
+	if (elapsed < 0) elapsed += TIMER_MAX;
+#endif	TIMER_MAX
+
+	/*
+	 *	Update current timer.
+	 */
+	mytimer->low_bits += elapsed;
+	mytimer->tstamp = 0;
+
+	if (mytimer->low_bits & TIMER_LOW_FULL) {
+		timer_normalize(mytimer);	/* SYSTEMMODE */
+	}
+
+	mytimer = &(active_threads[mycpu]->user_timer);
+
+	/*
+	 *	Record new timer.
+	 */
+	current_timer[mycpu] = mytimer;
+	mytimer->tstamp = ts;
+}
+
+/*
+ *	time_int_entry does interrupt entry timing.  Caller must lock out
+ *	interrupts and take a timestamp. ts is a timestamp taken after
+ *	interrupts were locked out.  new_timer is the new timer to
+ *	switch to.  This routine returns the currently running timer,
+ *	which MUST be pushed onto the stack by the caller, or otherwise
+ *	saved for time_int_exit.
+ */
+timer_t
+time_int_entry(ts,new_timer)
+unsigned	ts;
+timer_t	new_timer;
+{
+	int	elapsed;
+	int	mycpu;
+	timer_t	mytimer;
+
+	/*
+	 *	Calculate elapsed time.
+	 */
+	mycpu = cpu_number();
+	mytimer = current_timer[mycpu];
+
+	elapsed = ts - mytimer->tstamp;
+#ifdef	TIMER_MAX
+	if (elapsed < 0) elapsed += TIMER_MAX;
+#endif	TIMER_MAX
+
+	/*
+	 *	Update current timer.
+	 */
+	mytimer->low_bits += elapsed;
+	mytimer->tstamp = 0;
+
+	/*
+	 *	Switch to new timer, and save old one on stack.
+	 */
+	new_timer->tstamp = ts;
+	current_timer[mycpu] = new_timer;
+	return(mytimer);
+}
+
+/*
+ *	time_int_exit does interrupt exit timing.  Caller must lock out
+ *	interrupts and take a timestamp.  ts is a timestamp taken after
+ *	interrupts were locked out.  old_timer is the timer value pushed
+ *	onto the stack or otherwise saved after time_int_entry returned
+ *	it.
+ */
+void
+time_int_exit(ts, old_timer)
+unsigned	ts;
+timer_t	old_timer;
+{
+	int	elapsed;
+	int	mycpu;
+	timer_t	mytimer;
+
+	/*
+	 *	Calculate elapsed time.
+	 */
+	mycpu = cpu_number();
+	mytimer = current_timer[mycpu];
+	elapsed = ts - mytimer->tstamp;
+#ifdef	TIMER_MAX
+	if (elapsed < 0) elapsed += TIMER_MAX;
+#endif	TIMER_MAX
+
+	/*
+	 *	Update current timer.
+	 */
+	mytimer->low_bits += elapsed;
+	mytimer->tstamp = 0;
+
+	/*
+	 *	If normalization requested, do it.
+	 */
+	if (mytimer->low_bits & TIMER_LOW_FULL) {
+		timer_normalize(mytimer);
+	}
+	if (old_timer->low_bits & TIMER_LOW_FULL) {
+		timer_normalize(old_timer);
+	}
+
+	/*
+	 *	Start timer that was running before interrupt.
+	 */
+	old_timer->tstamp = ts;
+	current_timer[mycpu] = old_timer;
+}
+
+/*
+ *	timer_switch switches to a new timer.  The machine
+ *	dependent routine/macro get_timestamp must return a timestamp.
+ *	Caller must lock out interrupts.
+ */
+void
+timer_switch(new_timer)
+timer_t new_timer;
+{
+	int		elapsed;
+	int		mycpu;
+	timer_t		mytimer;
+	unsigned	ts;
+
+	/*
+	 *	Calculate elapsed time.
+	 */
+	mycpu = cpu_number();
+	mytimer = current_timer[mycpu];
+	ts = get_timestamp();
+	elapsed = ts - mytimer->tstamp;
+#ifdef	TIMER_MAX
+	if (elapsed < 0) elapsed += TIMER_MAX;
+#endif	TIMER_MAX
+
+	/*
+	 *	Update current timer.
+	 */
+	mytimer->low_bits += elapsed;
+	mytimer->tstamp = 0;
+
+	/*
+	 *	Normalization check
+	 */
+	if (mytimer->low_bits & TIMER_LOW_FULL) {
+		timer_normalize(mytimer);
+	}
+
+	/*
+	 *	Record new timer.
+	 */
+	current_timer[mycpu] = new_timer;
+	new_timer->tstamp = ts;
+}
+
+#endif	/* MACHINE_TIMER_ROUTINES */
+#endif	STAT_TIME
+
+/*
+ *	timer_normalize normalizes the value of a timer.  It is
+ *	called only rarely, to make sure low_bits never overflows.
+ */
+void timer_normalize(timer)
+register
+timer_t	timer;
+{
+	unsigned int	high_increment;
+
+	/*
+	 *	Calculate high_increment, then write high check field first
+	 *	followed by low and high.  timer_grab() reads these fields in
+	 *	reverse order so if high and high check match, we know
+	 *	that the values read are ok.
+	 */
+
+	high_increment = timer->low_bits/TIMER_HIGH_UNIT;
+	timer->high_bits_check += high_increment;
+	timer->low_bits %= TIMER_HIGH_UNIT;
+	timer->high_bits += high_increment;
+}
+
+/*
+ *	timer_grab() retrieves the value of a timer.
+ *
+ *	Critical scheduling code uses TIMER_DELTA macro in timer.h
+ *	(called from thread_timer_delta in sched.h).
+ *    
+ *      Keep coherent with db_time_grab below.
+ */
+
+static void timer_grab(timer, save)
+timer_t		timer;
+timer_save_t	save;
+{
+#if MACH_ASSERT
+  unsigned int passes=0;
+#endif
+	do {
+		(save)->high = (timer)->high_bits;
+		(save)->low = (timer)->low_bits;
+	/*
+	 *	If the timer was normalized while we were doing this,
+	 *	the high_bits value read above and the high_bits check
+	 *	value will not match because high_bits_check is the first
+	 *	field touched by the normalization procedure, and
+	 *	high_bits is the last.
+	 *
+	 *	Additions to timer only touch low bits and
+	 *	are therefore atomic with respect to this.
+	 */
+#if MACH_ASSERT
+		passes++;
+		assert((passes < 10000) ? (1) : ((timer->high_bits_check = save->high), 0));
+#endif		
+	} while ( (save)->high != (timer)->high_bits_check);
+}
+
+/*
+ *
+ * 	Db_timer_grab(): used by db_thread_read_times. An nonblocking
+ *      version of db_thread_get_times. Keep coherent with timer_grab
+ *      above.
+ *
+ */
+void db_timer_grab(timer, save)
+timer_t		timer;
+timer_save_t	save;
+{
+  /* Don't worry about coherency */
+
+  (save)->high = (timer)->high_bits;
+  (save)->low = (timer)->low_bits;
+}
+
+
+/*
+ *	timer_read reads the value of a timer into a time_value_t.  If the
+ *	timer was modified during the read, retry.  The value returned
+ *	is accurate to the last update; time accumulated by a running
+ *	timer since its last timestamp is not included.
+ */
+
+void
+timer_read(timer, tv)
+timer_t timer;
+register
+time_value_t *tv;
+{
+	timer_save_data_t	temp;
+
+	timer_grab(timer,&temp);
+	/*
+	 *	Normalize the result
+	 */
+#ifdef	TIMER_ADJUST
+	TIMER_ADJUST(&temp);
+#endif	TIMER_ADJUST
+	tv->seconds = temp.high + temp.low/1000000;
+	tv->microseconds = temp.low%1000000;
+
+}
+
+/*
+ *	thread_read_times reads the user and system times from a thread.
+ *	Time accumulated since last timestamp is not included.  Should
+ *	be called at splsched() to avoid having user and system times
+ *	be out of step.  Doesn't care if caller locked thread.
+ *
+ *      Needs to be kept coherent with thread_read_times ahead.
+ */
+void	thread_read_times(thread, user_time_p, system_time_p)
+	thread_t 	thread;
+	time_value_t	*user_time_p;
+	time_value_t	*system_time_p;
+{
+	timer_save_data_t	temp;
+	register timer_t	timer;
+
+	timer = &thread->user_timer;
+	timer_grab(timer, &temp);
+
+#ifdef	TIMER_ADJUST
+	TIMER_ADJUST(&temp);
+#endif	TIMER_ADJUST
+	user_time_p->seconds = temp.high + temp.low/1000000;
+	user_time_p->microseconds = temp.low % 1000000;
+
+	timer = &thread->system_timer;
+	timer_grab(timer, &temp);
+
+#ifdef	TIMER_ADJUST
+	TIMER_ADJUST(&temp);
+#endif	TIMER_ADJUST
+	system_time_p->seconds = temp.high + temp.low/1000000;
+	system_time_p->microseconds = temp.low % 1000000;
+}
+
+/*
+ *      Db_thread_read_times: A version of thread_read_times that
+ *      can be called by the debugger. This version does not call
+ *      timer_grab, which can block. Please keep it up to date with
+ *      thread_read_times above.
+ *
+ */
+void	db_thread_read_times(thread, user_time_p, system_time_p)
+	thread_t 	thread;
+	time_value_t	*user_time_p;
+	time_value_t	*system_time_p;
+{
+	timer_save_data_t	temp;
+	register timer_t	timer;
+
+	timer = &thread->user_timer;
+	db_timer_grab(timer, &temp);
+
+#ifdef	TIMER_ADJUST
+	TIMER_ADJUST(&temp);
+#endif	TIMER_ADJUST
+	user_time_p->seconds = temp.high + temp.low/1000000;
+	user_time_p->microseconds = temp.low % 1000000;
+
+	timer = &thread->system_timer;
+	timer_grab(timer, &temp);
+
+#ifdef	TIMER_ADJUST
+	TIMER_ADJUST(&temp);
+#endif	TIMER_ADJUST
+	system_time_p->seconds = temp.high + temp.low/1000000;
+	system_time_p->microseconds = temp.low % 1000000;
+}
+
+/*
+ *	timer_delta takes the difference of a saved timer value
+ *	and the current one, and updates the saved value to current.
+ *	The difference is returned as a function value.  See
+ *	TIMER_DELTA macro (timer.h) for optimization to this.
+ */
+
+unsigned
+timer_delta(timer, save)
+register
+timer_t	timer;
+timer_save_t	save;
+{
+	timer_save_data_t	new_save;
+	register unsigned	result;
+
+	timer_grab(timer,&new_save);
+	result = (new_save.high - save->high) * TIMER_HIGH_UNIT +
+		new_save.low - save->low;
+	save->high = new_save.high;
+	save->low = new_save.low;
+	return(result);
+}