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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.
*/
#ifndef _KERN_TIMER_H_
#define _KERN_TIMER_H_
#include <kern/macros.h>
#if STAT_TIME
/*
* Statistical timer definitions - use microseconds in timer, seconds
* in high unit field. No adjustment needed to convert to time_value_t
* as a result. Service timers once an hour.
*/
/*
* TIMER_MAX is needed if a 32-bit rollover timer needs to be adjusted for
* maximum value.
*/
#undef TIMER_MAX
/*
* TIMER_RATE is the rate of the timer in ticks per second. It is used to
* calculate percent cpu usage.
*/
#define TIMER_RATE 1000000
/*
* TIMER_HIGH_UNIT is the unit for high_bits in terms of low_bits.
* Setting it to TIMER_RATE makes the high unit seconds.
*/
#define TIMER_HIGH_UNIT TIMER_RATE
/*
* TIMER_ADJUST is used to adjust the value of a timer after it has been
* copied into a time_value_t. No adjustment is needed if high_bits is in
* seconds.
*/
#undef TIMER_ADJUST
/*
* MACHINE_TIMER_ROUTINES should defined if the timer routines are
* implemented in machine-dependent code (e.g. assembly language).
*/
#undef MACHINE_TIMER_ROUTINES
#else /* STAT_TIME */
/*
* Machine dependent definitions based on hardware support.
*/
#include <machine/timer.h>
#endif /* STAT_TIME */
/*
* Definitions for accurate timers. high_bits_check is a copy of
* high_bits that allows reader to verify that values read are ok.
*/
struct timer {
unsigned low_bits;
unsigned high_bits;
unsigned high_bits_check;
unsigned tstamp;
};
typedef struct timer timer_data_t;
typedef struct timer *timer_t;
/*
* Mask to check if low_bits is in danger of overflowing
*/
#define TIMER_LOW_FULL 0x80000000U
/*
* Kernel timers and current timer array. [Exported]
*/
extern timer_t current_timer[NCPUS];
extern timer_data_t kernel_timer[NCPUS];
/*
* save structure for timer readings. This is used to save timer
* readings for elapsed time computations.
*/
struct timer_save {
unsigned low;
unsigned high;
};
typedef struct timer_save timer_save_data_t, *timer_save_t;
/*
* Exported kernel interface to timers
*/
#if STAT_TIME
#define start_timer(timer)
#define timer_switch(timer)
#else /* STAT_TIME */
extern void start_timer(timer_t);
extern void timer_switch(timer_t);
#endif /* STAT_TIME */
extern void timer_read(timer_t, time_value_t *);
extern void thread_read_times(thread_t, time_value_t *, time_value_t *);
extern unsigned timer_delta(timer_t, timer_save_t);
extern void timer_normalize(timer_t);
extern void timer_init(timer_t);
#if STAT_TIME
/*
* Macro to bump timer values.
*/
#define timer_bump(timer, usec) \
MACRO_BEGIN \
(timer)->low_bits += usec; \
if ((timer)->low_bits & TIMER_LOW_FULL) { \
timer_normalize(timer); \
} \
MACRO_END
#else /* STAT_TIME */
/*
* Exported hardware interface to timers
*/
extern void time_trap_uentry(unsigned);
extern void time_trap_uexit(int);
extern timer_t time_int_entry(unsigned, timer_t);
extern void time_int_exit(unsigned, timer_t);
#endif /* STAT_TIME */
/*
* TIMER_DELTA finds the difference between a timer and a saved value,
* and updates the saved value. Look at high_bits check field after
* reading low because that's the first written by a normalize
* operation; this isn't necessary for current usage because
* this macro is only used when the timer can't be normalized:
* thread is not running, or running thread calls it on itself at
* splsched().
*/
#define TIMER_DELTA(timer, save, result) \
MACRO_BEGIN \
unsigned temp; \
\
temp = (timer).low_bits; \
if ((save).high != (timer).high_bits_check) { \
result += timer_delta(&(timer), &(save)); \
} \
else { \
result += temp - (save).low; \
(save).low = temp; \
} \
MACRO_END
extern void init_timers(void);
void timer_init(timer_t this_timer);
#endif /* _KERN_TIMER_H_ */
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