1 /*
2 * Mach Operating System
3 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
4 * All Rights Reserved.
5 *
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.
11 *
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.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie Mellon
24 * the rights to redistribute these changes.
25 */
26 /*
27 * HISTORY
28 * $Log: mach_factor.c,v $
29 * Revision 2.7 92/08/03 17:38:15 jfriedl
30 * removed silly prototypes
31 * [92/08/02 jfriedl]
32 *
33 * Revision 2.6 92/05/21 17:14:39 jfriedl
34 * Added void to to compute_mach_factor().
35 * [92/05/16 jfriedl]
36 *
37 * Revision 2.5 91/05/14 16:44:18 mrt
38 * Correcting copyright
39 *
40 * Revision 2.4 91/02/05 17:27:51 mrt
41 * Changed to new Mach copyright
42 * [91/02/01 16:14:56 mrt]
43 *
44 * Revision 2.3 90/06/02 14:55:09 rpd
45 * Removed host_load; host_info/HOST_LOAD_INFO supercedes it.
46 * [90/06/02 rpd]
47 *
48 * Updated to new processor set and scheduling technology.
49 * [90/03/26 22:11:20 rpd]
50 *
51 * Revision 2.2 90/03/14 21:10:38 rwd
52 * Added host_load call to get avenrun.
53 * [90/01/28 rwd]
54 *
55 * Revision 2.1 89/08/03 15:46:37 rwd
56 * Created.
57 *
58 * 20-Oct-88 David Golub (dbg) at Carnegie-Mellon University
59 * Fixed for MACH_KERNEL.
60 *
61 * 25-Mar-88 David Black (dlb) at Carnegie-Mellon University
62 * Added sched_load calculation.
63 *
64 * 4-Dec-87 David Black (dlb) at Carnegie-Mellon University
65 * Fix calculation to correctly account for threads that are
66 * actually on cpus. This used to work by accident because if a
67 * processor is not idle, its idle thread was on the local runq;
68 * this is no longer the case.
69 *
70 * 18-Nov-87 Avadis Tevanian (avie) at Carnegie-Mellon University
71 * Removed conditionals, compute every second.
72 *
73 */
74 /*
75 * File: kern/mach_factor.c
76 * Author: Avadis Tevanian, Jr.
77 * Date: 1986
78 *
79 * Compute the Mach Factor.
80 */
81
82 #include <cpus.h>
83
84 #include <mach/machine.h>
85 #include <mach/processor_info.h>
86 #include <kern/sched.h>
87 #include <kern/processor.h>
88 #include <kern/time_out.h>
89 #if MACH_KERNEL
90 #include <mach/kern_return.h>
91 #include <mach/port.h>
92 #endif MACH_KERNEL
93
94
95 long avenrun[3] = {0, 0, 0};
96 long mach_factor[3] = {0, 0, 0};
97
98 /*
99 * Values are scaled by LOAD_SCALE, defined in processor_info.h
100 */
101 static long fract[3] = {
102 800, /* (4.0/5.0) 5 second average */
103 966, /* (29.0/30.0) 30 second average */
104 983, /* (59.0/60.) 1 minute average */
105 };
106
107 void compute_mach_factor()
108 {
109 register processor_set_t pset;
110 register processor_t processor;
111 register int ncpus;
112 register int nthreads;
113 register long factor_now;
114 register long average_now;
115 register long load_now;
116
117 simple_lock(&all_psets_lock);
118 pset = (processor_set_t) queue_first(&all_psets);
119 while (!queue_end(&all_psets, (queue_entry_t)pset)) {
120
121 /*
122 * If no processors, this pset is in suspended animation.
123 * No load calculations are performed.
124 */
125 pset_lock(pset);
126 if((ncpus = pset->processor_count) > 0) {
127
128 /*
129 * Count number of threads.
130 */
131 nthreads = pset->runq.count;
132 processor = (processor_t) queue_first(&pset->processors);
133 while (!queue_end(&pset->processors,
134 (queue_entry_t)processor)) {
135 nthreads += processor->runq.count;
136 processor =
137 (processor_t) queue_next(&processor->processors);
138 }
139
140 /*
141 * account for threads on cpus.
142 */
143 nthreads += ncpus - pset->idle_count;
144
145 /*
146 * The current thread (running this calculation)
147 * doesn't count; it's always in the default pset.
148 */
149 if (pset == &default_pset)
150 nthreads -= 1;
151
152 if (nthreads > ncpus) {
153 factor_now = (ncpus * LOAD_SCALE) / (nthreads + 1);
154 load_now = (nthreads << SCHED_SHIFT) / ncpus;
155 }
156 else {
157 factor_now = (ncpus - nthreads) * LOAD_SCALE;
158 load_now = SCHED_SCALE;
159 }
160
161 /*
162 * Load average and mach factor calculations for
163 * those that ask about these things.
164 */
165
166 average_now = nthreads * LOAD_SCALE;
167
168 pset->mach_factor =
169 ((pset->mach_factor << 2) + factor_now)/5;
170 pset->load_average =
171 ((pset->load_average << 2) + average_now)/5;
172
173 /*
174 * And some ugly stuff to keep w happy.
175 */
176 if (pset == &default_pset) {
177 register int i;
178
179 for (i = 0; i < 3; i++) {
180 mach_factor[i] = ( (mach_factor[i]*fract[i])
181 + (factor_now*(LOAD_SCALE-fract[i])) )
182 / LOAD_SCALE;
183 avenrun[i] = ( (avenrun[i]*fract[i])
184 + (average_now*(LOAD_SCALE-fract[i])) )
185 / LOAD_SCALE;
186 }
187 }
188
189 /*
190 * sched_load is the only thing used by scheduler.
191 * It is always at least 1 (i.e. SCHED_SCALE).
192 */
193 pset->sched_load = (pset->sched_load + load_now) >> 1;
194 }
195
196 pset_unlock(pset);
197 pset = (processor_set_t) queue_next(&pset->all_psets);
198 }
199
200 simple_unlock(&all_psets_lock);
201 }
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