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 72uint32_t avenrun[3] = {0, 0, 0}; 73uint32_t mach_factor[3] = {0, 0, 0}; 74 75/* 76 * Values are scaled by LOAD_SCALE, defined in processor_info.h 77 */ 78#define base(n) ((n) << SCHED_TICK_SHIFT) 79#define frac(n) (((base(n) - 1) * LOAD_SCALE) / base(n)) 80 81static uint32_t fract[3] = { 82 frac(5), /* 5 second average */ 83 frac(30), /* 30 second average */ 84 frac(60), /* 1 minute average */ 85}; 86 87#undef base 88#undef frac 89 90static unsigned int sched_nrun; 91 92typedef void (*sched_avg_comp_t)( 93 void *param); 94 95#define SCHED_AVG_SECS(n) ((n) << SCHED_TICK_SHIFT) 96 97static struct sched_average { 98 sched_avg_comp_t comp; 99 void *param; 100 int period; 101 int tick; 102} sched_average[] = { 103 { compute_averunnable, &sched_nrun, SCHED_AVG_SECS(5), 0 }, 104 { compute_stack_target, NULL, SCHED_AVG_SECS(5), 1 }, 105 { NULL, NULL, 0, 0 } 106}; 107 108typedef struct sched_average *sched_average_t; 109 110void 111compute_averages(void) 112{ 113 int ncpus, nthreads, nshared; 114 uint32_t factor_now, average_now, load_now = 0; 115 sched_average_t avg; 116 117 /* 118 * Retrieve counts, ignoring 119 * the current thread. 120 */ 121 ncpus = processor_avail_count; 122 nthreads = sched_run_count - 1; 123 nshared = sched_share_count; 124 125 /* 126 * Load average and mach factor calculations for 127 * those which ask about these things. 128 */ 129 average_now = nthreads * LOAD_SCALE; 130 131 if (nthreads > ncpus) 132 factor_now = (ncpus * LOAD_SCALE) / (nthreads + 1); 133 else 134 factor_now = (ncpus - nthreads) * LOAD_SCALE; 135 136 sched_mach_factor = ((sched_mach_factor << 2) + factor_now) / 5; 137 sched_load_average = ((sched_load_average << 2) + average_now) / 5; 138 139 /* 140 * Compute the timeshare priority 141 * conversion factor based on loading. 142 */ 143 if (nshared > nthreads) 144 nshared = nthreads; 145 146 if (nshared > ncpus) { 147 if (ncpus > 1) 148 load_now = nshared / ncpus; 149 else 150 load_now = nshared; 151 152 if (load_now > NRQS - 1) 153 load_now = NRQS - 1; 154 } 155 156 /* 157 * The conversion factor consists of 158 * two components: a fixed value based 159 * on the absolute time unit, and a 160 * dynamic portion based on loading. 161 * 162 * Zero loading results in a out of range 163 * shift count. Accumulated usage is ignored 164 * during conversion and new usage deltas 165 * are discarded. 166 */ 167 sched_pri_shift = sched_fixed_shift - sched_load_shifts[load_now]; 168 169 /* 170 * Sample total running threads. 171 */ 172 sched_nrun = nthreads; 173 174 /* 175 * Compute old-style Mach load averages. 176 */ 177 { 178 register int i; 179 180 for (i = 0; i < 3; i++) { 181 mach_factor[i] = ((mach_factor[i] * fract[i]) + 182 (factor_now * (LOAD_SCALE - fract[i]))) / LOAD_SCALE; 183 184 avenrun[i] = ((avenrun[i] * fract[i]) + 185 (average_now * (LOAD_SCALE - fract[i]))) / LOAD_SCALE; 186 } 187 } 188 189 /* 190 * Compute averages in other components. 191 */ 192 for (avg = sched_average; avg->comp != NULL; ++avg) { 193 if (++avg->tick >= avg->period) { 194 (*avg->comp)(avg->param); 195 avg->tick = 0; 196 } 197 } 198} 199