Annotation of XNU/osfmk/kern/sched.h, revision 1.1

1.1     ! root        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  [email protected]
        !            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:  *     File:   sched.h
        !            54:  *     Author: Avadis Tevanian, Jr.
        !            55:  *     Date:   1985
        !            56:  *
        !            57:  *     Header file for scheduler.
        !            58:  *
        !            59:  */
        !            60: 
        !            61: #ifndef        _KERN_SCHED_H_
        !            62: #define _KERN_SCHED_H_
        !            63: 
        !            64: #include <cpus.h>
        !            65: #include <simple_clock.h>
        !            66: #include <stat_time.h>
        !            67: 
        !            68: #include <mach/policy.h>
        !            69: #include <kern/kern_types.h>
        !            70: #include <kern/queue.h>
        !            71: #include <kern/lock.h>
        !            72: #include <kern/macro_help.h>
        !            73: 
        !            74: #if    STAT_TIME
        !            75: 
        !            76: /*
        !            77:  *     Statistical timing uses microseconds as timer units.  15 bit shift
        !            78:  *     yields priorities.  PRI_SHIFT_2 isn't needed.
        !            79:  */
        !            80: #define PRI_SHIFT      15
        !            81: 
        !            82: #else  /* STAT_TIME */
        !            83: 
        !            84: /*
        !            85:  *     Otherwise machine provides shift(s) based on time units it uses.
        !            86:  */
        !            87: #include <machine/sched_param.h>
        !            88: 
        !            89: #endif /* STAT_TIME */
        !            90: 
        !            91: #define        NRQS            128                             /* 128 run queues per cpu */
        !            92: #define NRQBM          (NRQS / 32)             /* number of run queue bit maps */
        !            93: 
        !            94: #define MAXPRI         (NRQS-1)
        !            95: #define LPRI           (IDLEPRI+2)             /* lowest pri reachable w/o depress */
        !            96: #define MINPRI         (IDLEPRI+1)             /* lowest legal priority schedulable */
        !            97: #define        IDLEPRI         0                               /* idle thread priority */
        !            98: #define DEPRESSPRI     MINPRI                  /* depress priority */
        !            99: 
        !           100: /*
        !           101:  *     Default base priorities for threads.
        !           102:  */
        !           103: #define        BASEPRI_KERNEL          MAXPRI
        !           104: #define BASEPRI_SYSTEM         (BASEPRI_KERNEL - (NRQS / 4))
        !           105: #define BASEPRI_SERVER         (BASEPRI_SYSTEM - (NRQS / 8))
        !           106: #define BASEPRI_USER           (BASEPRI_SERVER - (NRQS / 8))
        !           107: 
        !           108: /*
        !           109:  *     Macro to check for invalid priorities.
        !           110:  */
        !           111: #define invalid_pri(pri) ((pri) < MINPRI || (pri) > MAXPRI)
        !           112: 
        !           113: struct run_queue {
        !           114:        queue_head_t            runq[NRQS];                     /* one for each priority */
        !           115:        decl_simple_lock_data(,lock)                    /* one lock for all queues */
        !           116:        int                                     bitmap[NRQBM];          /* run queue bitmap array */
        !           117:        int                                     highq;                          /* highest runnable queue */
        !           118:        int                                     count;                          /* # of runnable threads */
        !           119:        int                                     depress_count;          /* # of depressed threads */
        !           120: };
        !           121: 
        !           122: typedef struct run_queue       *run_queue_t;
        !           123: #define RUN_QUEUE_NULL         ((run_queue_t) 0)
        !           124: 
        !           125: #define csw_needed(thread, processor) (                                                                                \
        !           126:        ((thread)->state & TH_SUSP)                                                                             ||              \
        !           127:        ((processor)->first_quantum?                                                                                    \
        !           128:         ((processor)->runq.highq > (thread)->sched_pri                         ||                      \
        !           129:          (processor)->processor_set->runq.highq > (thread)->sched_pri) :               \
        !           130:         ((processor)->runq.highq >= (thread)->sched_pri                        ||                      \
        !           131:          (processor)->processor_set->runq.highq >= (thread)->sched_pri))       )
        !           132: 
        !           133: /*
        !           134:  *     Scheduler routines.
        !           135:  */
        !           136: 
        !           137: /* Remove thread from its run queue */
        !           138: extern run_queue_t     rem_runq(
        !           139:                                        thread_t        thread);
        !           140: 
        !           141: /* Mach factor computation (in mach_factor.c) */
        !           142: extern void            compute_mach_factor(void);
        !           143: 
        !           144: /* Update threads quantum (in priority.c) */
        !           145: extern void            thread_quantum_update(
        !           146:                                        int                     mycpu,
        !           147:                                        thread_t        thread,
        !           148:                                        int                     nticks,
        !           149:                                        int                     state);
        !           150: 
        !           151: extern queue_head_t    action_queue;   /* assign/shutdown queue */
        !           152: 
        !           153: decl_simple_lock_data(,action_lock)
        !           154: 
        !           155: extern int             min_quantum;    /* defines max context switch rate */
        !           156: 
        !           157: /*
        !           158:  *     Shift structures for holding update shifts.  Actual computation
        !           159:  *     is  usage = (usage >> shift1) +/- (usage >> abs(shift2))  where the
        !           160:  *     +/- is determined by the sign of shift 2.
        !           161:  */
        !           162: struct shift {
        !           163:        int     shift1;
        !           164:        int     shift2;
        !           165: };
        !           166: 
        !           167: typedef        struct shift    *shift_t, shift_data_t;
        !           168: 
        !           169: /*
        !           170:  *     sched_tick increments once a second.  Used to age priorities.
        !           171:  */
        !           172: 
        !           173: extern unsigned        sched_tick;
        !           174: 
        !           175: #define SCHED_SCALE    128
        !           176: #define SCHED_SHIFT    7
        !           177: 
        !           178: /*
        !           179:  *     thread_timer_delta macro takes care of both thread timers.
        !           180:  */
        !           181: 
        !           182: #define thread_timer_delta(thread)                                             \
        !           183: MACRO_BEGIN                                                                                                    \
        !           184:        register unsigned       delta;                                                          \
        !           185:                                                                                                                        \
        !           186:        delta = 0;                                                                                              \
        !           187:        TIMER_DELTA((thread)->system_timer,                                             \
        !           188:                                        (thread)->system_timer_save, delta);    \
        !           189:        TIMER_DELTA((thread)->user_timer,                                               \
        !           190:                                        (thread)->user_timer_save, delta);              \
        !           191:        (thread)->cpu_delta += delta;                                                   \
        !           192:        (thread)->sched_delta += (delta *                                               \
        !           193:                                        (thread)->processor_set->sched_load);   \
        !           194: MACRO_END
        !           195: 
        !           196: #if    SIMPLE_CLOCK
        !           197: /*
        !           198:  *     sched_usec is an exponential average of number of microseconds
        !           199:  *     in a second for clock drift compensation.
        !           200:  */
        !           201: 
        !           202: extern int     sched_usec;
        !           203: #endif /* SIMPLE_CLOCK */
        !           204: 
        !           205: #endif /* _KERN_SCHED_H_ */

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