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1 /*
2 * Copyright (c) 2000-2007 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28 /*
29 * @OSF_COPYRIGHT@
30 */
31 /*
32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34 * All Rights Reserved.
35 *
36 * Permission to use, copy, modify and distribute this software and its
37 * documentation is hereby granted, provided that both the copyright
38 * notice and this permission notice appear in all copies of the
39 * software, derivative works or modified versions, and any portions
40 * thereof, and that both notices appear in supporting documentation.
41 *
42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45 *
46 * Carnegie Mellon requests users of this software to return to
47 *
48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
49 * School of Computer Science
50 * Carnegie Mellon University
51 * Pittsburgh PA 15213-3890
52 *
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
55 */
56 /*
57 */
58 /*
59 * Author: Avadis Tevanian, Jr.
60 * Date: 1986
61 *
62 * Compute various averages.
63 */
64
65 #include <mach/mach_types.h>
66
67 #include <kern/sched.h>
68 #include <kern/assert.h>
69 #include <kern/processor.h>
70 #include <kern/thread.h>
71
72 uint32_t avenrun[3] = {0, 0, 0};
73 uint32_t mach_factor[3] = {0, 0, 0};
74
75 #if defined(CONFIG_SCHED_TRADITIONAL)
76 /*
77 * Values are scaled by LOAD_SCALE, defined in processor_info.h
78 */
79 #define base(n) ((n) << SCHED_TICK_SHIFT)
80 #define frac(n) (((base(n) - 1) * LOAD_SCALE) / base(n))
81
82 static uint32_t fract[3] = {
83 frac(5), /* 5 second average */
84 frac(30), /* 30 second average */
85 frac(60), /* 1 minute average */
86 };
87
88 #undef base
89 #undef frac
90
91 #endif /* CONFIG_SCHED_TRADITIONAL */
92
93 static unsigned int sched_nrun;
94
95 typedef void (*sched_avg_comp_t)(
96 void *param);
97
98 static struct sched_average {
99 sched_avg_comp_t comp;
100 void *param;
101 int period; /* in seconds */
102 uint64_t deadline;
103 } sched_average[] = {
104 { compute_averunnable, &sched_nrun, 5, 0 },
105 { compute_stack_target, NULL, 5, 1 },
106 { compute_memory_pressure, NULL, 1, 0 },
107 { compute_zone_gc_throttle, NULL, 60, 0 },
108 { compute_pageout_gc_throttle, NULL, 1, 0 },
109 { compute_pmap_gc_throttle, NULL, 60, 0 },
110 { NULL, NULL, 0, 0 }
111 };
112
113 typedef struct sched_average *sched_average_t;
114
115 void
116 compute_averages(void)
117 {
118 int ncpus, nthreads, nshared;
119 uint32_t factor_now, average_now, load_now = 0;
120 sched_average_t avg;
121 uint64_t abstime;
122
123 /*
124 * Retrieve counts, ignoring
125 * the current thread.
126 */
127 ncpus = processor_avail_count;
128 nthreads = sched_run_count - 1;
129 nshared = sched_share_count;
130
131 /*
132 * Load average and mach factor calculations for
133 * those which ask about these things.
134 */
135 average_now = nthreads * LOAD_SCALE;
136
137 if (nthreads > ncpus)
138 factor_now = (ncpus * LOAD_SCALE) / (nthreads + 1);
139 else
140 factor_now = (ncpus - nthreads) * LOAD_SCALE;
141
142 sched_mach_factor = ((sched_mach_factor << 2) + factor_now) / 5;
143 sched_load_average = ((sched_load_average << 2) + average_now) / 5;
144
145 /*
146 * Compute the timeshare priority
147 * conversion factor based on loading.
148 */
149 if (nshared > nthreads)
150 nshared = nthreads;
151
152 if (nshared > ncpus) {
153 if (ncpus > 1)
154 load_now = nshared / ncpus;
155 else
156 load_now = nshared;
157
158 if (load_now > NRQS - 1)
159 load_now = NRQS - 1;
160 }
161
162 /*
163 * Sample total running threads.
164 */
165 sched_nrun = nthreads;
166
167 #if defined(CONFIG_SCHED_TRADITIONAL)
168
169 /*
170 * The conversion factor consists of
171 * two components: a fixed value based
172 * on the absolute time unit, and a
173 * dynamic portion based on loading.
174 *
175 * Zero loading results in a out of range
176 * shift count. Accumulated usage is ignored
177 * during conversion and new usage deltas
178 * are discarded.
179 */
180 sched_pri_shift = sched_fixed_shift - sched_load_shifts[load_now];
181
182 /*
183 * Compute old-style Mach load averages.
184 */
185 {
186 register int i;
187
188 for (i = 0; i < 3; i++) {
189 mach_factor[i] = ((mach_factor[i] * fract[i]) +
190 (factor_now * (LOAD_SCALE - fract[i]))) / LOAD_SCALE;
191
192 avenrun[i] = ((avenrun[i] * fract[i]) +
193 (average_now * (LOAD_SCALE - fract[i]))) / LOAD_SCALE;
194 }
195 }
196 #endif /* CONFIG_SCHED_TRADITIONAL */
197
198 /*
199 * Compute averages in other components.
200 */
201 abstime = mach_absolute_time();
202 for (avg = sched_average; avg->comp != NULL; ++avg) {
203 if (abstime >= avg->deadline) {
204 (*avg->comp)(avg->param);
205 avg->deadline = abstime + avg->period * sched_one_second_interval;
206 }
207 }
208 }