osfmk/kern/timer.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * @OSF_COPYRIGHT@
  27  */
  28 /*
  29  * Mach Operating System
  30  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  31  * All Rights Reserved.
  32  *
  33  * Permission to use, copy, modify and distribute this software and its
  34  * documentation is hereby granted, provided that both the copyright
  35  * notice and this permission notice appear in all copies of the
  36  * software, derivative works or modified versions, and any portions
  37  * thereof, and that both notices appear in supporting documentation.
  38  *
  39  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  40  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  41  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  42  *
  43  * Carnegie Mellon requests users of this software to return to
  44  *
  45  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  46  *  School of Computer Science
  47  *  Carnegie Mellon University
  48  *  Pittsburgh PA 15213-3890
  49  *
  50  * any improvements or extensions that they make and grant Carnegie Mellon
  51  * the rights to redistribute these changes.
  52  */
  53 /*
  54  */
  55
  56 #ifndef _KERN_TIMER_H_
  57 #define _KERN_TIMER_H_
  58
  59 #include <cpus.h>
  60 #include <stat_time.h>
  61
  62 #include <kern/macro_help.h>
  63 #include <kern/kern_types.h>
  64
  65 #if     STAT_TIME
  66 /*
  67  *      Statistical timer definitions - use microseconds in timer, seconds
  68  *      in high unit field.  No adjustment needed to convert to time_value_t
  69  *      as a result.  Service timers once an hour.
  70  */
  71
  72 #define TIMER_RATE      1000000
  73 #define TIMER_HIGH_UNIT TIMER_RATE
  74 #undef  TIMER_ADJUST
  75
  76 #else   /* STAT_TIME */
  77 /*
  78  *      Machine dependent definitions based on hardware support.
  79  */
  80
  81 #include <machine/timer.h>
  82
  83 #endif  /* STAT_TIME */
  84
  85 /*
  86  *      Definitions for accurate timers.  high_bits_check is a copy of
  87  *      high_bits that allows reader to verify that values read are ok.
  88  */
  89
  90 struct timer {
  91         unsigned        low_bits;
  92         unsigned        high_bits;
  93         unsigned        high_bits_check;
  94         unsigned        tstamp;
  95 };
  96
  97 typedef struct timer            timer_data_t;
  98 typedef struct timer            *timer_t;
  99
 100 /*
 101  *      Mask to check if low_bits is in danger of overflowing
 102  */
 103
 104 #define TIMER_LOW_FULL  0x80000000
 105
 106 /*
 107  *      Kernel timers and current timer array.  [Exported]
 108  */
 109
 110 extern timer_t          current_timer[NCPUS];
 111 extern timer_data_t     kernel_timer[NCPUS];
 112
 113 /*
 114  *      save structure for timer readings.  This is used to save timer
 115  *      readings for elapsed time computations.
 116  */
 117
 118 struct timer_save {
 119         unsigned        low;
 120         unsigned        high;
 121 };
 122
 123 typedef struct timer_save       timer_save_data_t, *timer_save_t;
 124
 125 /*
 126  *      Exported kernel interface to timers
 127  */
 128
 129 #if     STAT_TIME
 130 #define start_timer(timer)
 131 #define timer_switch(timer)
 132 #else   /* STAT_TIME */
 133 /* Start timer for this cpu */
 134 extern void             start_timer(
 135                                 timer_t         timer);
 136
 137 /* Switch to a new timer */
 138 extern void             timer_switch(
 139                                 timer_t         new_timer);
 140 #endif  /* STAT_TIME */
 141
 142 /* Initialize timer module */
 143 extern void             init_timers(void);
 144
 145 /*
 146  * Initializes a single timer.
 147  */
 148 extern void             timer_init(
 149                                 timer_t this_timer);
 150
 151 /* Normalize timer value */
 152 extern void             timer_normalize(
 153                                 timer_t timer);
 154
 155 /* Read value of timer into tv */
 156 extern void             timer_read(
 157                                 timer_t timer,
 158                                 time_value_t *tv);
 159
 160 /* Read thread times */
 161 extern void             thread_read_times(
 162                                 thread_t        thread,
 163                                 time_value_t    *user_time_p,
 164                                 time_value_t    *system_time_p);
 165
 166 /* Compute timer difference */
 167 extern unsigned         timer_delta(
 168                                 timer_t         timer,
 169                                 timer_save_t    save);
 170
 171 #if     STAT_TIME
 172 /*
 173  *      Macro to bump timer values.
 174  */
 175 #define timer_bump(timer, usec)                                 \
 176 MACRO_BEGIN                                                     \
 177         (timer)->low_bits += usec;                              \
 178         if ((timer)->low_bits & TIMER_LOW_FULL) {               \
 179                 timer_normalize(timer);                         \
 180         }                                                       \
 181 MACRO_END
 182
 183 #else   /* STAT_TIME */
 184 /*
 185  *      Exported hardware interface to timers
 186  */
 187 /* Time trap entry */
 188 extern void             time_trap_uentry(
 189                                 unsigned        ts);
 190
 191 /* Time trap exit */
 192 extern void             time_trap_uexit(
 193                                 unsigned        ts);
 194
 195 /* Time interrupt entry */
 196 extern timer_t          time_int_entry(
 197                                 unsigned        ts,
 198                                 timer_t         new_timer);
 199
 200 /* Time interrrupt exit */
 201 extern void             time_int_exit(
 202                                 unsigned        ts,
 203                                 timer_t         old_timer);
 204
 205 #endif  /* STAT_TIME */
 206
 207 /*
 208  *      TIMER_DELTA finds the difference between a timer and a saved value,
 209  *      and updates the saved value.  Look at high_bits check field after
 210  *      reading low because that's the first written by a normalize
 211  *      operation; this isn't necessary for current usage because
 212  *      this macro is only used when the timer can't be normalized:
 213  *      thread is not running, or running thread calls it on itself at
 214  *      splsched().
 215  */
 216
 217 #define TIMER_DELTA(timer, save, result)                        \
 218 MACRO_BEGIN                                                     \
 219         register unsigned       temp;                           \
 220                                                                 \
 221         temp = (timer).low_bits;                                \
 222         if ((save).high != (timer).high_bits_check) {           \
 223                 result += timer_delta(&(timer), &(save));       \
 224         }                                                       \
 225         else {                                                  \
 226                 result += temp - (save).low;                    \
 227                 (save).low = temp;                              \
 228         }                                                       \
 229 MACRO_END
 230
 231 #endif  /* _KERN_TIMER_H_ */