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1.1.1.2 root 1: /*
1.1 root 2: * Mach Operating System
3: * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
4: * All Rights Reserved.
1.1.1.2 root 5: *
1.1 root 6: * Permission to use, copy, modify and distribute this software and its
7: * documentation is hereby granted, provided that both the copyright
8: * notice and this permission notice appear in all copies of the
9: * software, derivative works or modified versions, and any portions
10: * thereof, and that both notices appear in supporting documentation.
1.1.1.2 root 11: *
1.1 root 12: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
13: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
1.1.1.2 root 15: *
1.1 root 16: * Carnegie Mellon requests users of this software to return to
1.1.1.2 root 17: *
1.1 root 18: * Software Distribution Coordinator or [email protected]
19: * School of Computer Science
20: * Carnegie Mellon University
21: * Pittsburgh PA 15213-3890
1.1.1.2 root 22: *
1.1 root 23: * any improvements or extensions that they make and grant Carnegie Mellon
24: * the rights to redistribute these changes.
25: */
26: /*
27: * File: sched.h
28: * Author: Avadis Tevanian, Jr.
29: * Date: 1985
30: *
31: * Header file for scheduler.
32: *
33: */
34:
35: #ifndef _KERN_SCHED_H_
36: #define _KERN_SCHED_H_
37:
38: #include <kern/queue.h>
39: #include <kern/lock.h>
1.1.1.3 root 40: #include <kern/kern_types.h>
1.1.1.5 ! root 41: #include <kern/macros.h>
1.1 root 42:
43: #if MACH_FIXPRI
44: #include <mach/policy.h>
1.1.1.2 root 45: #endif /* MACH_FIXPRI */
1.1 root 46:
47: #if STAT_TIME
48:
49: /*
50: * Statistical timing uses microseconds as timer units. 18 bit shift
51: * yields priorities. PRI_SHIFT_2 isn't needed.
52: */
53: #define PRI_SHIFT 18
54:
1.1.1.2 root 55: #else /* STAT_TIME */
1.1 root 56:
57: /*
58: * Otherwise machine provides shift(s) based on time units it uses.
59: */
60: #include <machine/sched_param.h>
61:
1.1.1.2 root 62: #endif /* STAT_TIME */
1.1.1.3 root 63: #define NRQS 50 /* 50 run queues per cpu */
1.1 root 64:
65: struct run_queue {
66: queue_head_t runq[NRQS]; /* one for each priority */
67: decl_simple_lock_data(, lock) /* one lock for all queues */
68: int low; /* low queue value */
69: int count; /* count of threads runable */
70: };
71:
72: typedef struct run_queue *run_queue_t;
73: #define RUN_QUEUE_NULL ((run_queue_t) 0)
74:
75: #if MACH_FIXPRI
76: /*
77: * NOTE: For fixed priority threads, first_quantum indicates
78: * whether context switch at same priority is ok. For timeshareing
79: * it indicates whether preempt is ok.
80: */
81:
82: #define csw_needed(thread, processor) ((thread)->state & TH_SUSP || \
83: ((processor)->runq.count > 0) || \
84: ((thread)->policy == POLICY_TIMESHARE && \
85: (processor)->first_quantum == FALSE && \
86: (processor)->processor_set->runq.count > 0 && \
87: (processor)->processor_set->runq.low <= \
88: (thread)->sched_pri) || \
89: ((thread)->policy == POLICY_FIXEDPRI && \
90: (processor)->processor_set->runq.count > 0 && \
91: ((((processor)->first_quantum == FALSE) && \
92: ((processor)->processor_set->runq.low <= \
93: (thread)->sched_pri)) || \
94: ((processor)->processor_set->runq.low < \
95: (thread)->sched_pri))))
96:
1.1.1.2 root 97: #else /* MACH_FIXPRI */
1.1 root 98: #define csw_needed(thread, processor) ((thread)->state & TH_SUSP || \
99: ((processor)->runq.count > 0) || \
100: ((processor)->first_quantum == FALSE && \
101: ((processor)->processor_set->runq.count > 0 && \
102: (processor)->processor_set->runq.low <= \
103: ((thread)->sched_pri))))
1.1.1.2 root 104: #endif /* MACH_FIXPRI */
1.1 root 105:
106: /*
107: * Scheduler routines.
108: */
109:
1.1.1.3 root 110: extern struct run_queue *rem_runq(thread_t);
111: extern struct thread *choose_thread(processor_t);
1.1 root 112: extern queue_head_t action_queue; /* assign/shutdown queue */
113: decl_simple_lock_data(extern,action_lock);
114:
115: extern int min_quantum; /* defines max context switch rate */
116:
117: /*
118: * Default base priorities for threads.
119: */
120: #define BASEPRI_SYSTEM 6
1.1.1.3 root 121: #define BASEPRI_USER 25
1.1 root 122:
123: /*
124: * Macro to check for invalid priorities.
125: */
126:
127: #define invalid_pri(pri) (((pri) < 0) || ((pri) >= NRQS))
128:
129: /*
130: * Shift structures for holding update shifts. Actual computation
131: * is usage = (usage >> shift1) +/- (usage >> abs(shift2)) where the
132: * +/- is determined by the sign of shift 2.
133: */
134: struct shift {
135: int shift1;
136: int shift2;
137: };
138:
139: typedef struct shift *shift_t, shift_data_t;
140:
141: /*
142: * sched_tick increments once a second. Used to age priorities.
143: */
144:
145: extern unsigned sched_tick;
146:
147: #define SCHED_SCALE 128
148: #define SCHED_SHIFT 7
149:
150: /*
151: * thread_timer_delta macro takes care of both thread timers.
152: */
153:
154: #define thread_timer_delta(thread) \
155: MACRO_BEGIN \
1.1.1.4 root 156: unsigned delta; \
1.1 root 157: \
158: delta = 0; \
159: TIMER_DELTA((thread)->system_timer, \
160: (thread)->system_timer_save, delta); \
161: TIMER_DELTA((thread)->user_timer, \
162: (thread)->user_timer_save, delta); \
163: (thread)->cpu_delta += delta; \
164: (thread)->sched_delta += delta * \
165: (thread)->processor_set->sched_load; \
166: MACRO_END
167:
168: #if SIMPLE_CLOCK
169: /*
170: * sched_usec is an exponential average of number of microseconds
171: * in a second for clock drift compensation.
172: */
173:
174: extern int sched_usec;
1.1.1.2 root 175: #endif /* SIMPLE_CLOCK */
1.1 root 176:
1.1.1.2 root 177: #endif /* _KERN_SCHED_H_ */
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