osfmk/kern/timer.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50 /*
  51  */
  52
  53 #ifndef _KERN_TIMER_H_
  54 #define _KERN_TIMER_H_
  55
  56 #include <cpus.h>
  57 #include <stat_time.h>
  58
  59 #include <kern/macro_help.h>
  60 #include <kern/kern_types.h>
  61
  62 #if     STAT_TIME
  63 /*
  64  *      Statistical timer definitions - use microseconds in timer, seconds
  65  *      in high unit field.  No adjustment needed to convert to time_value_t
  66  *      as a result.  Service timers once an hour.
  67  */
  68
  69 #define TIMER_RATE      1000000
  70 #define TIMER_HIGH_UNIT TIMER_RATE
  71 #undef  TIMER_ADJUST
  72
  73 #else   /* STAT_TIME */
  74 /*
  75  *      Machine dependent definitions based on hardware support.
  76  */
  77
  78 #include <machine/timer.h>
  79
  80 #endif  /* STAT_TIME */
  81
  82 /*
  83  *      Definitions for accurate timers.  high_bits_check is a copy of
  84  *      high_bits that allows reader to verify that values read are ok.
  85  */
  86
  87 struct timer {
  88         unsigned        low_bits;
  89         unsigned        high_bits;
  90         unsigned        high_bits_check;
  91         unsigned        tstamp;
  92 };
  93
  94 typedef struct timer            timer_data_t;
  95 typedef struct timer            *timer_t;
  96
  97 /*
  98  *      Mask to check if low_bits is in danger of overflowing
  99  */
 100
 101 #define TIMER_LOW_FULL  0x80000000
 102
 103 /*
 104  *      Kernel timers and current timer array.  [Exported]
 105  */
 106
 107 extern timer_t          current_timer[NCPUS];
 108 extern timer_data_t     kernel_timer[NCPUS];
 109
 110 /*
 111  *      save structure for timer readings.  This is used to save timer
 112  *      readings for elapsed time computations.
 113  */
 114
 115 struct timer_save {
 116         unsigned        low;
 117         unsigned        high;
 118 };
 119
 120 typedef struct timer_save       timer_save_data_t, *timer_save_t;
 121
 122 /*
 123  *      Exported kernel interface to timers
 124  */
 125
 126 #if     STAT_TIME
 127 #define start_timer(timer)
 128 #define timer_switch(timer)
 129 #else   /* STAT_TIME */
 130 /* Start timer for this cpu */
 131 extern void             start_timer(
 132                                 timer_t         timer);
 133
 134 /* Switch to a new timer */
 135 extern void             timer_switch(
 136                                 timer_t         new_timer);
 137 #endif  /* STAT_TIME */
 138
 139 /* Initialize timer module */
 140 extern void             init_timers(void);
 141
 142 /*
 143  * Initializes a single timer.
 144  */
 145 extern void             timer_init(
 146                                 timer_t this_timer);
 147
 148 /* Normalize timer value */
 149 extern void             timer_normalize(
 150                                 timer_t timer);
 151
 152 /* Read value of timer into tv */
 153 extern void             timer_read(
 154                                 timer_t timer,
 155                                 time_value_t *tv);
 156
 157 /* Read thread times */
 158 extern void             thread_read_times(
 159                                 thread_t        thread,
 160                                 time_value_t    *user_time_p,
 161                                 time_value_t    *system_time_p);
 162
 163 /* Compute timer difference */
 164 extern unsigned         timer_delta(
 165                                 timer_t         timer,
 166                                 timer_save_t    save);
 167
 168 #if     STAT_TIME
 169 /*
 170  *      Macro to bump timer values.
 171  */
 172 #define timer_bump(timer, usec)                                 \
 173 MACRO_BEGIN                                                     \
 174         (timer)->low_bits += usec;                              \
 175         if ((timer)->low_bits & TIMER_LOW_FULL) {               \
 176                 timer_normalize(timer);                         \
 177         }                                                       \
 178 MACRO_END
 179
 180 #else   /* STAT_TIME */
 181 /*
 182  *      Exported hardware interface to timers
 183  */
 184 /* Time trap entry */
 185 extern void             time_trap_uentry(
 186                                 unsigned        ts);
 187
 188 /* Time trap exit */
 189 extern void             time_trap_uexit(
 190                                 unsigned        ts);
 191
 192 /* Time interrupt entry */
 193 extern timer_t          time_int_entry(
 194                                 unsigned        ts,
 195                                 timer_t         new_timer);
 196
 197 /* Time interrrupt exit */
 198 extern void             time_int_exit(
 199                                 unsigned        ts,
 200                                 timer_t         old_timer);
 201
 202 #endif  /* STAT_TIME */
 203
 204 /*
 205  *      TIMER_DELTA finds the difference between a timer and a saved value,
 206  *      and updates the saved value.  Look at high_bits check field after
 207  *      reading low because that's the first written by a normalize
 208  *      operation; this isn't necessary for current usage because
 209  *      this macro is only used when the timer can't be normalized:
 210  *      thread is not running, or running thread calls it on itself at
 211  *      splsched().
 212  */
 213
 214 #define TIMER_DELTA(timer, save, result)                        \
 215 MACRO_BEGIN                                                     \
 216         register unsigned       temp;                           \
 217                                                                 \
 218         temp = (timer).low_bits;                                \
 219         if ((save).high != (timer).high_bits_check) {           \
 220                 result += timer_delta(&(timer), &(save));       \
 221         }                                                       \
 222         else {                                                  \
 223                 result += temp - (save).low;                    \
 224                 (save).low = temp;                              \
 225         }                                                       \
 226 MACRO_END
 227
 228 #endif  /* _KERN_TIMER_H_ */