blob: 4b34ade2332baaa50bb1ca1af9c45e1a9893d321 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * drivers/cpufreq/cpufreq_ondemand.c
3 *
4 * Copyright (C) 2001 Russell King
5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * Jun Nakajima <jun.nakajima@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13#include <linux/kernel.h>
14#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/cpufreq.h>
Andrew Morton138a01282006-06-23 03:31:19 -070017#include <linux/cpu.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/jiffies.h>
19#include <linux/kernel_stat.h>
akpm@osdl.org3fc54d32006-01-13 15:54:22 -080020#include <linux/mutex.h>
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -070021#include <linux/hrtimer.h>
22#include <linux/tick.h>
23#include <linux/ktime.h>
Thomas Renninger9411b4e2009-02-04 11:54:04 +010024#include <linux/sched.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
26/*
27 * dbs is used in this file as a shortform for demandbased switching
28 * It helps to keep variable names smaller, simpler
29 */
30
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -070031#define DEF_FREQUENCY_DOWN_DIFFERENTIAL (10)
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#define DEF_FREQUENCY_UP_THRESHOLD (80)
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -070033#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3)
34#define MICRO_FREQUENCY_UP_THRESHOLD (95)
Thomas Renningercef96152009-04-22 13:48:29 +020035#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000)
Dave Jonesc29f1402005-05-31 19:03:50 -070036#define MIN_FREQUENCY_UP_THRESHOLD (11)
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#define MAX_FREQUENCY_UP_THRESHOLD (100)
38
Dave Jones32ee8c32006-02-28 00:43:23 -050039/*
40 * The polling frequency of this governor depends on the capability of
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 * the processor. Default polling frequency is 1000 times the transition
Dave Jones32ee8c32006-02-28 00:43:23 -050042 * latency of the processor. The governor will work on any processor with
43 * transition latency <= 10mS, using appropriate sampling
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 * rate.
45 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
46 * this governor will not work.
47 * All times here are in uS.
48 */
Dave Jonesdf8b59b2005-09-20 12:39:35 -070049#define MIN_SAMPLING_RATE_RATIO (2)
Thomas Renninger112124a2009-02-04 11:55:12 +010050
Thomas Renningercef96152009-04-22 13:48:29 +020051static unsigned int min_sampling_rate;
52
Thomas Renninger112124a2009-02-04 11:55:12 +010053#define LATENCY_MULTIPLIER (1000)
Thomas Renningercef96152009-04-22 13:48:29 +020054#define MIN_LATENCY_MULTIPLIER (100)
Thomas Renninger1c256242007-10-02 13:28:12 -070055#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
David Howellsc4028952006-11-22 14:57:56 +000057static void do_dbs_timer(struct work_struct *work);
Thomas Renninger0e625ac2009-07-24 15:25:06 +020058static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
59 unsigned int event);
60
61#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
62static
63#endif
64struct cpufreq_governor cpufreq_gov_ondemand = {
65 .name = "ondemand",
66 .governor = cpufreq_governor_dbs,
67 .max_transition_latency = TRANSITION_LATENCY_LIMIT,
68 .owner = THIS_MODULE,
69};
David Howellsc4028952006-11-22 14:57:56 +000070
71/* Sampling types */
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -080072enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
74struct cpu_dbs_info_s {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070075 cputime64_t prev_cpu_idle;
76 cputime64_t prev_cpu_wall;
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -070077 cputime64_t prev_cpu_nice;
Dave Jones32ee8c32006-02-28 00:43:23 -050078 struct cpufreq_policy *cur_policy;
Dave Jones2b03f892009-01-18 01:43:44 -050079 struct delayed_work work;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040080 struct cpufreq_frequency_table *freq_table;
81 unsigned int freq_lo;
82 unsigned int freq_lo_jiffies;
83 unsigned int freq_hi_jiffies;
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -080084 int cpu;
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -070085 unsigned int sample_type:1;
86 /*
87 * percpu mutex that serializes governor limit change with
88 * do_dbs_timer invocation. We do not want do_dbs_timer to run
89 * when user is changing the governor or limits.
90 */
91 struct mutex timer_mutex;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092};
Tejun Heo245b2e72009-06-24 15:13:48 +090093static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
95static unsigned int dbs_enable; /* number of CPUs using this policy */
96
Venkatesh Pallipadi4ec223d2006-06-21 15:18:34 -070097/*
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -070098 * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -070099 * different CPUs. It protects dbs_enable in governor start/stop.
Venkatesh Pallipadi4ec223d2006-06-21 15:18:34 -0700100 */
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700101static DEFINE_MUTEX(dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700103static struct workqueue_struct *kondemand_wq;
Andi Kleen6810b542006-05-08 15:17:31 +0200104
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400105static struct dbs_tuners {
Dave Jones32ee8c32006-02-28 00:43:23 -0500106 unsigned int sampling_rate;
Dave Jones32ee8c32006-02-28 00:43:23 -0500107 unsigned int up_threshold;
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700108 unsigned int down_differential;
Dave Jones32ee8c32006-02-28 00:43:23 -0500109 unsigned int ignore_nice;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400110 unsigned int powersave_bias;
111} dbs_tuners_ins = {
Dave Jones32ee8c32006-02-28 00:43:23 -0500112 .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700113 .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
Eric Piel9cbad612006-03-10 11:35:27 +0200114 .ignore_nice = 0,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400115 .powersave_bias = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116};
117
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700118static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
119 cputime64_t *wall)
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700120{
Venki Pallipadiea487612007-06-20 14:26:24 -0700121 cputime64_t idle_time;
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700122 cputime64_t cur_wall_time;
Venki Pallipadiea487612007-06-20 14:26:24 -0700123 cputime64_t busy_time;
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700124
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700125 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
Venki Pallipadiea487612007-06-20 14:26:24 -0700126 busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
127 kstat_cpu(cpu).cpustat.system);
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700128
Venki Pallipadiea487612007-06-20 14:26:24 -0700129 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
130 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
131 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500132 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
Venki Pallipadiea487612007-06-20 14:26:24 -0700133
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700134 idle_time = cputime64_sub(cur_wall_time, busy_time);
135 if (wall)
Pallipadi, Venkatesh54c9a352009-11-11 16:50:29 -0800136 *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700137
Pallipadi, Venkatesh54c9a352009-11-11 16:50:29 -0800138 return (cputime64_t)jiffies_to_usecs(idle_time);
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700139}
140
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700141static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
142{
143 u64 idle_time = get_cpu_idle_time_us(cpu, wall);
144
145 if (idle_time == -1ULL)
146 return get_cpu_idle_time_jiffy(cpu, wall);
147
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700148 return idle_time;
149}
150
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400151/*
152 * Find right freq to be set now with powersave_bias on.
153 * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
154 * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
155 */
Adrian Bunkb5ecf602006-08-13 23:00:08 +0200156static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
157 unsigned int freq_next,
158 unsigned int relation)
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400159{
160 unsigned int freq_req, freq_reduc, freq_avg;
161 unsigned int freq_hi, freq_lo;
162 unsigned int index = 0;
163 unsigned int jiffies_total, jiffies_hi, jiffies_lo;
Tejun Heo245b2e72009-06-24 15:13:48 +0900164 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
165 policy->cpu);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400166
167 if (!dbs_info->freq_table) {
168 dbs_info->freq_lo = 0;
169 dbs_info->freq_lo_jiffies = 0;
170 return freq_next;
171 }
172
173 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
174 relation, &index);
175 freq_req = dbs_info->freq_table[index].frequency;
176 freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000;
177 freq_avg = freq_req - freq_reduc;
178
179 /* Find freq bounds for freq_avg in freq_table */
180 index = 0;
181 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
182 CPUFREQ_RELATION_H, &index);
183 freq_lo = dbs_info->freq_table[index].frequency;
184 index = 0;
185 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
186 CPUFREQ_RELATION_L, &index);
187 freq_hi = dbs_info->freq_table[index].frequency;
188
189 /* Find out how long we have to be in hi and lo freqs */
190 if (freq_hi == freq_lo) {
191 dbs_info->freq_lo = 0;
192 dbs_info->freq_lo_jiffies = 0;
193 return freq_lo;
194 }
195 jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
196 jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
197 jiffies_hi += ((freq_hi - freq_lo) / 2);
198 jiffies_hi /= (freq_hi - freq_lo);
199 jiffies_lo = jiffies_total - jiffies_hi;
200 dbs_info->freq_lo = freq_lo;
201 dbs_info->freq_lo_jiffies = jiffies_lo;
202 dbs_info->freq_hi_jiffies = jiffies_hi;
203 return freq_hi;
204}
205
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700206static void ondemand_powersave_bias_init_cpu(int cpu)
207{
Tejun Heo384be2b2009-08-14 14:41:02 +0900208 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700209 dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
210 dbs_info->freq_lo = 0;
211}
212
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400213static void ondemand_powersave_bias_init(void)
214{
215 int i;
216 for_each_online_cpu(i) {
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700217 ondemand_powersave_bias_init_cpu(i);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400218 }
219}
220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221/************************** sysfs interface ************************/
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200222
223static ssize_t show_sampling_rate_max(struct kobject *kobj,
224 struct attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225{
Thomas Renninger4f4d1ad2009-04-22 13:48:31 +0200226 printk_once(KERN_INFO "CPUFREQ: ondemand sampling_rate_max "
227 "sysfs file is deprecated - used by: %s\n", current->comm);
Thomas Renningercef96152009-04-22 13:48:29 +0200228 return sprintf(buf, "%u\n", -1U);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229}
230
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200231static ssize_t show_sampling_rate_min(struct kobject *kobj,
232 struct attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233{
Thomas Renningercef96152009-04-22 13:48:29 +0200234 return sprintf(buf, "%u\n", min_sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235}
236
Dave Jones32ee8c32006-02-28 00:43:23 -0500237#define define_one_ro(_name) \
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200238static struct global_attr _name = \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239__ATTR(_name, 0444, show_##_name, NULL)
240
241define_one_ro(sampling_rate_max);
242define_one_ro(sampling_rate_min);
243
244/* cpufreq_ondemand Governor Tunables */
245#define show_one(file_name, object) \
246static ssize_t show_##file_name \
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200247(struct kobject *kobj, struct attribute *attr, char *buf) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248{ \
249 return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
250}
251show_one(sampling_rate, sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252show_one(up_threshold, up_threshold);
Alexander Clouter001893c2005-12-01 01:09:25 -0800253show_one(ignore_nice_load, ignore_nice);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400254show_one(powersave_bias, powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200256/*** delete after deprecation time ***/
257
258#define DEPRECATION_MSG(file_name) \
259 printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs " \
260 "interface is deprecated - " #file_name "\n");
261
262#define show_one_old(file_name) \
263static ssize_t show_##file_name##_old \
264(struct cpufreq_policy *unused, char *buf) \
265{ \
266 printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs " \
267 "interface is deprecated - " #file_name "\n"); \
268 return show_##file_name(NULL, NULL, buf); \
269}
270show_one_old(sampling_rate);
271show_one_old(up_threshold);
272show_one_old(ignore_nice_load);
273show_one_old(powersave_bias);
274show_one_old(sampling_rate_min);
275show_one_old(sampling_rate_max);
276
277#define define_one_ro_old(object, _name) \
278static struct freq_attr object = \
279__ATTR(_name, 0444, show_##_name##_old, NULL)
280
281define_one_ro_old(sampling_rate_min_old, sampling_rate_min);
282define_one_ro_old(sampling_rate_max_old, sampling_rate_max);
283
284/*** delete after deprecation time ***/
285
286static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
287 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288{
289 unsigned int input;
290 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700291 ret = sscanf(buf, "%u", &input);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700292 if (ret != 1)
293 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800295 mutex_lock(&dbs_mutex);
Thomas Renningercef96152009-04-22 13:48:29 +0200296 dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800297 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
299 return count;
300}
301
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200302static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
303 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304{
305 unsigned int input;
306 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700307 ret = sscanf(buf, "%u", &input);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308
Dave Jones32ee8c32006-02-28 00:43:23 -0500309 if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
Dave Jonesc29f1402005-05-31 19:03:50 -0700310 input < MIN_FREQUENCY_UP_THRESHOLD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 return -EINVAL;
312 }
313
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700314 mutex_lock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 dbs_tuners_ins.up_threshold = input;
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800316 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
318 return count;
319}
320
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200321static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
322 const char *buf, size_t count)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700323{
324 unsigned int input;
325 int ret;
326
327 unsigned int j;
Dave Jones32ee8c32006-02-28 00:43:23 -0500328
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700329 ret = sscanf(buf, "%u", &input);
Dave Jones2b03f892009-01-18 01:43:44 -0500330 if (ret != 1)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700331 return -EINVAL;
332
Dave Jones2b03f892009-01-18 01:43:44 -0500333 if (input > 1)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700334 input = 1;
Dave Jones32ee8c32006-02-28 00:43:23 -0500335
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800336 mutex_lock(&dbs_mutex);
Dave Jones2b03f892009-01-18 01:43:44 -0500337 if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800338 mutex_unlock(&dbs_mutex);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700339 return count;
340 }
341 dbs_tuners_ins.ignore_nice = input;
342
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700343 /* we need to re-evaluate prev_cpu_idle */
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700344 for_each_online_cpu(j) {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700345 struct cpu_dbs_info_s *dbs_info;
Tejun Heo245b2e72009-06-24 15:13:48 +0900346 dbs_info = &per_cpu(od_cpu_dbs_info, j);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700347 dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
348 &dbs_info->prev_cpu_wall);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500349 if (dbs_tuners_ins.ignore_nice)
350 dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
351
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700352 }
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800353 mutex_unlock(&dbs_mutex);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700354
355 return count;
356}
357
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200358static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
359 const char *buf, size_t count)
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400360{
361 unsigned int input;
362 int ret;
363 ret = sscanf(buf, "%u", &input);
364
365 if (ret != 1)
366 return -EINVAL;
367
368 if (input > 1000)
369 input = 1000;
370
371 mutex_lock(&dbs_mutex);
372 dbs_tuners_ins.powersave_bias = input;
373 ondemand_powersave_bias_init();
374 mutex_unlock(&dbs_mutex);
375
376 return count;
377}
378
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379#define define_one_rw(_name) \
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200380static struct global_attr _name = \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381__ATTR(_name, 0644, show_##_name, store_##_name)
382
383define_one_rw(sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384define_one_rw(up_threshold);
Alexander Clouter001893c2005-12-01 01:09:25 -0800385define_one_rw(ignore_nice_load);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400386define_one_rw(powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387
Dave Jones2b03f892009-01-18 01:43:44 -0500388static struct attribute *dbs_attributes[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 &sampling_rate_max.attr,
390 &sampling_rate_min.attr,
391 &sampling_rate.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 &up_threshold.attr,
Alexander Clouter001893c2005-12-01 01:09:25 -0800393 &ignore_nice_load.attr,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400394 &powersave_bias.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 NULL
396};
397
398static struct attribute_group dbs_attr_group = {
399 .attrs = dbs_attributes,
400 .name = "ondemand",
401};
402
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200403/*** delete after deprecation time ***/
404
405#define write_one_old(file_name) \
406static ssize_t store_##file_name##_old \
407(struct cpufreq_policy *unused, const char *buf, size_t count) \
408{ \
409 printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs " \
410 "interface is deprecated - " #file_name "\n"); \
411 return store_##file_name(NULL, NULL, buf, count); \
412}
413write_one_old(sampling_rate);
414write_one_old(up_threshold);
415write_one_old(ignore_nice_load);
416write_one_old(powersave_bias);
417
418#define define_one_rw_old(object, _name) \
419static struct freq_attr object = \
420__ATTR(_name, 0644, show_##_name##_old, store_##_name##_old)
421
422define_one_rw_old(sampling_rate_old, sampling_rate);
423define_one_rw_old(up_threshold_old, up_threshold);
424define_one_rw_old(ignore_nice_load_old, ignore_nice_load);
425define_one_rw_old(powersave_bias_old, powersave_bias);
426
427static struct attribute *dbs_attributes_old[] = {
428 &sampling_rate_max_old.attr,
429 &sampling_rate_min_old.attr,
430 &sampling_rate_old.attr,
431 &up_threshold_old.attr,
432 &ignore_nice_load_old.attr,
433 &powersave_bias_old.attr,
434 NULL
435};
436
437static struct attribute_group dbs_attr_group_old = {
438 .attrs = dbs_attributes_old,
439 .name = "ondemand",
440};
441
442/*** delete after deprecation time ***/
443
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444/************************** sysfs end ************************/
445
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700446static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447{
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700448 unsigned int max_load_freq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449
450 struct cpufreq_policy *policy;
451 unsigned int j;
452
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400453 this_dbs_info->freq_lo = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 policy = this_dbs_info->cur_policy;
Venki Pallipadiea487612007-06-20 14:26:24 -0700455
Dave Jones32ee8c32006-02-28 00:43:23 -0500456 /*
Dave Jonesc29f1402005-05-31 19:03:50 -0700457 * Every sampling_rate, we check, if current idle time is less
458 * than 20% (default), then we try to increase frequency
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700459 * Every sampling_rate, we look for a the lowest
Dave Jonesc29f1402005-05-31 19:03:50 -0700460 * frequency which can sustain the load while keeping idle time over
461 * 30%. If such a frequency exist, we try to decrease to this frequency.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 *
Dave Jones32ee8c32006-02-28 00:43:23 -0500463 * Any frequency increase takes it to the maximum frequency.
464 * Frequency reduction happens at minimum steps of
465 * 5% (default) of current frequency
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 */
467
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700468 /* Get Absolute Load - in terms of freq */
469 max_load_freq = 0;
470
Rusty Russell835481d2009-01-04 05:18:06 -0800471 for_each_cpu(j, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 struct cpu_dbs_info_s *j_dbs_info;
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700473 cputime64_t cur_wall_time, cur_idle_time;
474 unsigned int idle_time, wall_time;
475 unsigned int load, load_freq;
476 int freq_avg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477
Tejun Heo245b2e72009-06-24 15:13:48 +0900478 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700479
480 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
481
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700482 wall_time = (unsigned int) cputime64_sub(cur_wall_time,
483 j_dbs_info->prev_cpu_wall);
484 j_dbs_info->prev_cpu_wall = cur_wall_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700486 idle_time = (unsigned int) cputime64_sub(cur_idle_time,
487 j_dbs_info->prev_cpu_idle);
488 j_dbs_info->prev_cpu_idle = cur_idle_time;
489
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500490 if (dbs_tuners_ins.ignore_nice) {
491 cputime64_t cur_nice;
492 unsigned long cur_nice_jiffies;
493
494 cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
495 j_dbs_info->prev_cpu_nice);
496 /*
497 * Assumption: nice time between sampling periods will
498 * be less than 2^32 jiffies for 32 bit sys
499 */
500 cur_nice_jiffies = (unsigned long)
501 cputime64_to_jiffies64(cur_nice);
502
503 j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
504 idle_time += jiffies_to_usecs(cur_nice_jiffies);
505 }
506
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700507 if (unlikely(!wall_time || wall_time < idle_time))
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700508 continue;
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700509
510 load = 100 * (wall_time - idle_time) / wall_time;
511
512 freq_avg = __cpufreq_driver_getavg(policy, j);
513 if (freq_avg <= 0)
514 freq_avg = policy->cur;
515
516 load_freq = load * freq_avg;
517 if (load_freq > max_load_freq)
518 max_load_freq = load_freq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 }
520
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700521 /* Check for frequency increase */
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700522 if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) {
Dave Jonesc11420a2005-05-31 19:03:48 -0700523 /* if we are already at full speed then break out early */
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400524 if (!dbs_tuners_ins.powersave_bias) {
525 if (policy->cur == policy->max)
526 return;
Dave Jones32ee8c32006-02-28 00:43:23 -0500527
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400528 __cpufreq_driver_target(policy, policy->max,
529 CPUFREQ_RELATION_H);
530 } else {
531 int freq = powersave_bias_target(policy, policy->max,
532 CPUFREQ_RELATION_H);
533 __cpufreq_driver_target(policy, freq,
534 CPUFREQ_RELATION_L);
535 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 return;
537 }
538
539 /* Check for frequency decrease */
Dave Jonesc29f1402005-05-31 19:03:50 -0700540 /* if we cannot reduce the frequency anymore, break out early */
541 if (policy->cur == policy->min)
542 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
Dave Jonesc29f1402005-05-31 19:03:50 -0700544 /*
545 * The optimal frequency is the frequency that is the lowest that
546 * can support the current CPU usage without triggering the up
547 * policy. To be safe, we focus 10 points under the threshold.
548 */
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700549 if (max_load_freq <
550 (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) *
551 policy->cur) {
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700552 unsigned int freq_next;
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700553 freq_next = max_load_freq /
554 (dbs_tuners_ins.up_threshold -
555 dbs_tuners_ins.down_differential);
Venkatesh Pallipadidfde5d62006-10-03 12:38:45 -0700556
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400557 if (!dbs_tuners_ins.powersave_bias) {
558 __cpufreq_driver_target(policy, freq_next,
559 CPUFREQ_RELATION_L);
560 } else {
561 int freq = powersave_bias_target(policy, freq_next,
562 CPUFREQ_RELATION_L);
563 __cpufreq_driver_target(policy, freq,
564 CPUFREQ_RELATION_L);
565 }
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700566 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567}
568
David Howellsc4028952006-11-22 14:57:56 +0000569static void do_dbs_timer(struct work_struct *work)
Dave Jones32ee8c32006-02-28 00:43:23 -0500570{
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800571 struct cpu_dbs_info_s *dbs_info =
572 container_of(work, struct cpu_dbs_info_s, work.work);
573 unsigned int cpu = dbs_info->cpu;
574 int sample_type = dbs_info->sample_type;
575
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400576 /* We want all CPUs to do sampling nearly on same jiffy */
577 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
David Howellsc4028952006-11-22 14:57:56 +0000578
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400579 delay -= jiffies % delay;
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700580 mutex_lock(&dbs_info->timer_mutex);
Venkatesh Pallipadi56463b72007-02-05 16:12:45 -0800581
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400582 /* Common NORMAL_SAMPLE setup */
David Howellsc4028952006-11-22 14:57:56 +0000583 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400584 if (!dbs_tuners_ins.powersave_bias ||
David Howellsc4028952006-11-22 14:57:56 +0000585 sample_type == DBS_NORMAL_SAMPLE) {
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400586 dbs_check_cpu(dbs_info);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400587 if (dbs_info->freq_lo) {
588 /* Setup timer for SUB_SAMPLE */
David Howellsc4028952006-11-22 14:57:56 +0000589 dbs_info->sample_type = DBS_SUB_SAMPLE;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400590 delay = dbs_info->freq_hi_jiffies;
591 }
592 } else {
593 __cpufreq_driver_target(dbs_info->cur_policy,
Dave Jones2b03f892009-01-18 01:43:44 -0500594 dbs_info->freq_lo, CPUFREQ_RELATION_H);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400595 }
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400596 queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700597 mutex_unlock(&dbs_info->timer_mutex);
Dave Jones32ee8c32006-02-28 00:43:23 -0500598}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800600static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601{
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400602 /* We want all CPUs to do sampling nearly on same jiffy */
603 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
604 delay -= jiffies % delay;
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700605
David Howellsc4028952006-11-22 14:57:56 +0000606 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
Venki Pallipadi28287032007-05-08 00:27:47 -0700607 INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800608 queue_delayed_work_on(dbs_info->cpu, kondemand_wq, &dbs_info->work,
Dave Jones2b03f892009-01-18 01:43:44 -0500609 delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610}
611
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700612static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613{
Mathieu Desnoyersb14893a2009-05-17 10:30:45 -0400614 cancel_delayed_work_sync(&dbs_info->work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615}
616
617static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
618 unsigned int event)
619{
620 unsigned int cpu = policy->cpu;
621 struct cpu_dbs_info_s *this_dbs_info;
622 unsigned int j;
Jeff Garzik914f7c32006-10-20 14:31:00 -0700623 int rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624
Tejun Heo245b2e72009-06-24 15:13:48 +0900625 this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626
627 switch (event) {
628 case CPUFREQ_GOV_START:
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700629 if ((!cpu_online(cpu)) || (!policy->cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 return -EINVAL;
631
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800632 mutex_lock(&dbs_mutex);
Jeff Garzik914f7c32006-10-20 14:31:00 -0700633
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200634 rc = sysfs_create_group(&policy->kobj, &dbs_attr_group_old);
Jeff Garzik914f7c32006-10-20 14:31:00 -0700635 if (rc) {
Jeff Garzik914f7c32006-10-20 14:31:00 -0700636 mutex_unlock(&dbs_mutex);
637 return rc;
638 }
639
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700640 dbs_enable++;
Rusty Russell835481d2009-01-04 05:18:06 -0800641 for_each_cpu(j, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 struct cpu_dbs_info_s *j_dbs_info;
Tejun Heo245b2e72009-06-24 15:13:48 +0900643 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 j_dbs_info->cur_policy = policy;
Dave Jones32ee8c32006-02-28 00:43:23 -0500645
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700646 j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
647 &j_dbs_info->prev_cpu_wall);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500648 if (dbs_tuners_ins.ignore_nice) {
649 j_dbs_info->prev_cpu_nice =
650 kstat_cpu(j).cpustat.nice;
651 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 }
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800653 this_dbs_info->cpu = cpu;
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700654 ondemand_powersave_bias_init_cpu(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 /*
656 * Start the timerschedule work, when this governor
657 * is used for first time
658 */
659 if (dbs_enable == 1) {
660 unsigned int latency;
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200661
662 rc = sysfs_create_group(cpufreq_global_kobject,
663 &dbs_attr_group);
664 if (rc) {
665 mutex_unlock(&dbs_mutex);
666 return rc;
667 }
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 /* policy latency is in nS. Convert it to uS first */
Dave Jonesdf8b59b2005-09-20 12:39:35 -0700670 latency = policy->cpuinfo.transition_latency / 1000;
671 if (latency == 0)
672 latency = 1;
Thomas Renningercef96152009-04-22 13:48:29 +0200673 /* Bring kernel and HW constraints together */
674 min_sampling_rate = max(min_sampling_rate,
675 MIN_LATENCY_MULTIPLIER * latency);
676 dbs_tuners_ins.sampling_rate =
677 max(min_sampling_rate,
678 latency * LATENCY_MULTIPLIER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 }
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800680 mutex_unlock(&dbs_mutex);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700681
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200682 mutex_init(&this_dbs_info->timer_mutex);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700683 dbs_timer_init(this_dbs_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 break;
685
686 case CPUFREQ_GOV_STOP:
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700687 dbs_timer_exit(this_dbs_info);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700688
689 mutex_lock(&dbs_mutex);
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200690 sysfs_remove_group(&policy->kobj, &dbs_attr_group_old);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700691 mutex_destroy(&this_dbs_info->timer_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 dbs_enable--;
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800693 mutex_unlock(&dbs_mutex);
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200694 if (!dbs_enable)
695 sysfs_remove_group(cpufreq_global_kobject,
696 &dbs_attr_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
698 break;
699
700 case CPUFREQ_GOV_LIMITS:
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700701 mutex_lock(&this_dbs_info->timer_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 if (policy->max < this_dbs_info->cur_policy->cur)
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700703 __cpufreq_driver_target(this_dbs_info->cur_policy,
Dave Jones2b03f892009-01-18 01:43:44 -0500704 policy->max, CPUFREQ_RELATION_H);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 else if (policy->min > this_dbs_info->cur_policy->cur)
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700706 __cpufreq_driver_target(this_dbs_info->cur_policy,
Dave Jones2b03f892009-01-18 01:43:44 -0500707 policy->min, CPUFREQ_RELATION_L);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700708 mutex_unlock(&this_dbs_info->timer_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 break;
710 }
711 return 0;
712}
713
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714static int __init cpufreq_gov_dbs_init(void)
715{
Akinobu Mita888a7942008-07-14 12:00:45 +0900716 int err;
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700717 cputime64_t wall;
Andrea Righi4f6e6b92008-09-18 10:43:40 +0000718 u64 idle_time;
719 int cpu = get_cpu();
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700720
Andrea Righi4f6e6b92008-09-18 10:43:40 +0000721 idle_time = get_cpu_idle_time_us(cpu, &wall);
722 put_cpu();
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700723 if (idle_time != -1ULL) {
724 /* Idle micro accounting is supported. Use finer thresholds */
725 dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
726 dbs_tuners_ins.down_differential =
727 MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
Thomas Renningercef96152009-04-22 13:48:29 +0200728 /*
729 * In no_hz/micro accounting case we set the minimum frequency
730 * not depending on HZ, but fixed (very low). The deferred
731 * timer might skip some samples if idle/sleeping as needed.
732 */
733 min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
734 } else {
735 /* For correct statistics, we need 10 ticks for each measure */
736 min_sampling_rate =
737 MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700738 }
Akinobu Mita888a7942008-07-14 12:00:45 +0900739
Venkatesh Pallipadi56463b72007-02-05 16:12:45 -0800740 kondemand_wq = create_workqueue("kondemand");
741 if (!kondemand_wq) {
742 printk(KERN_ERR "Creation of kondemand failed\n");
743 return -EFAULT;
744 }
Akinobu Mita888a7942008-07-14 12:00:45 +0900745 err = cpufreq_register_governor(&cpufreq_gov_ondemand);
746 if (err)
747 destroy_workqueue(kondemand_wq);
748
749 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750}
751
752static void __exit cpufreq_gov_dbs_exit(void)
753{
Thomas Renninger1c256242007-10-02 13:28:12 -0700754 cpufreq_unregister_governor(&cpufreq_gov_ondemand);
Venkatesh Pallipadi56463b72007-02-05 16:12:45 -0800755 destroy_workqueue(kondemand_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756}
757
758
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700759MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
760MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
761MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
Dave Jones2b03f892009-01-18 01:43:44 -0500762 "Low Latency Frequency Transition capable processors");
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700763MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
Johannes Weiner69157192008-01-17 15:21:08 -0800765#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
766fs_initcall(cpufreq_gov_dbs_init);
767#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768module_init(cpufreq_gov_dbs_init);
Johannes Weiner69157192008-01-17 15:21:08 -0800769#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770module_exit(cpufreq_gov_dbs_exit);