blob: 629b3ec698e2d4ac0f88f88e26f9e95e91e96150 [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)
David C Niemi3f78a9f2010-10-06 16:54:24 -040033#define DEF_SAMPLING_DOWN_FACTOR (1)
34#define MAX_SAMPLING_DOWN_FACTOR (100000)
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -070035#define MICRO_FREQUENCY_DOWN_DIFFERENTIAL (3)
36#define MICRO_FREQUENCY_UP_THRESHOLD (95)
Thomas Renningercef96152009-04-22 13:48:29 +020037#define MICRO_FREQUENCY_MIN_SAMPLE_RATE (10000)
Dave Jonesc29f1402005-05-31 19:03:50 -070038#define MIN_FREQUENCY_UP_THRESHOLD (11)
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#define MAX_FREQUENCY_UP_THRESHOLD (100)
40
Dave Jones32ee8c32006-02-28 00:43:23 -050041/*
42 * The polling frequency of this governor depends on the capability of
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 * the processor. Default polling frequency is 1000 times the transition
Dave Jones32ee8c32006-02-28 00:43:23 -050044 * latency of the processor. The governor will work on any processor with
45 * transition latency <= 10mS, using appropriate sampling
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 * rate.
47 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
48 * this governor will not work.
49 * All times here are in uS.
50 */
Dave Jonesdf8b59b2005-09-20 12:39:35 -070051#define MIN_SAMPLING_RATE_RATIO (2)
Thomas Renninger112124a2009-02-04 11:55:12 +010052
Thomas Renningercef96152009-04-22 13:48:29 +020053static unsigned int min_sampling_rate;
54
Thomas Renninger112124a2009-02-04 11:55:12 +010055#define LATENCY_MULTIPLIER (1000)
Thomas Renningercef96152009-04-22 13:48:29 +020056#define MIN_LATENCY_MULTIPLIER (100)
Thomas Renninger1c256242007-10-02 13:28:12 -070057#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
David Howellsc4028952006-11-22 14:57:56 +000059static void do_dbs_timer(struct work_struct *work);
Thomas Renninger0e625ac2009-07-24 15:25:06 +020060static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
61 unsigned int event);
62
63#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
64static
65#endif
66struct cpufreq_governor cpufreq_gov_ondemand = {
67 .name = "ondemand",
68 .governor = cpufreq_governor_dbs,
69 .max_transition_latency = TRANSITION_LATENCY_LIMIT,
70 .owner = THIS_MODULE,
71};
David Howellsc4028952006-11-22 14:57:56 +000072
73/* Sampling types */
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -080074enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
76struct cpu_dbs_info_s {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070077 cputime64_t prev_cpu_idle;
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -070078 cputime64_t prev_cpu_iowait;
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070079 cputime64_t prev_cpu_wall;
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -070080 cputime64_t prev_cpu_nice;
Dave Jones32ee8c32006-02-28 00:43:23 -050081 struct cpufreq_policy *cur_policy;
Dave Jones2b03f892009-01-18 01:43:44 -050082 struct delayed_work work;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040083 struct cpufreq_frequency_table *freq_table;
84 unsigned int freq_lo;
85 unsigned int freq_lo_jiffies;
86 unsigned int freq_hi_jiffies;
David C Niemi3f78a9f2010-10-06 16:54:24 -040087 unsigned int rate_mult;
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -080088 int cpu;
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -070089 unsigned int sample_type:1;
90 /*
91 * percpu mutex that serializes governor limit change with
92 * do_dbs_timer invocation. We do not want do_dbs_timer to run
93 * when user is changing the governor or limits.
94 */
95 struct mutex timer_mutex;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096};
Tejun Heo245b2e72009-06-24 15:13:48 +090097static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
99static unsigned int dbs_enable; /* number of CPUs using this policy */
100
Venkatesh Pallipadi4ec223d2006-06-21 15:18:34 -0700101/*
Thomas Renninger326c86d2011-03-03 21:31:27 +0100102 * dbs_mutex protects dbs_enable in governor start/stop.
Venkatesh Pallipadi4ec223d2006-06-21 15:18:34 -0700103 */
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700104static DEFINE_MUTEX(dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400106static struct dbs_tuners {
Dave Jones32ee8c32006-02-28 00:43:23 -0500107 unsigned int sampling_rate;
Dave Jones32ee8c32006-02-28 00:43:23 -0500108 unsigned int up_threshold;
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700109 unsigned int down_differential;
Dave Jones32ee8c32006-02-28 00:43:23 -0500110 unsigned int ignore_nice;
David C Niemi3f78a9f2010-10-06 16:54:24 -0400111 unsigned int sampling_down_factor;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400112 unsigned int powersave_bias;
Arjan van de Ven19379b12010-05-09 08:26:51 -0700113 unsigned int io_is_busy;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400114} dbs_tuners_ins = {
Dave Jones32ee8c32006-02-28 00:43:23 -0500115 .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
David C Niemi3f78a9f2010-10-06 16:54:24 -0400116 .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700117 .down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
Eric Piel9cbad612006-03-10 11:35:27 +0200118 .ignore_nice = 0,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400119 .powersave_bias = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120};
121
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700122static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,
123 cputime64_t *wall)
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700124{
Venki Pallipadiea487612007-06-20 14:26:24 -0700125 cputime64_t idle_time;
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700126 cputime64_t cur_wall_time;
Venki Pallipadiea487612007-06-20 14:26:24 -0700127 cputime64_t busy_time;
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700128
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700129 cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
Venki Pallipadiea487612007-06-20 14:26:24 -0700130 busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,
131 kstat_cpu(cpu).cpustat.system);
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700132
Venki Pallipadiea487612007-06-20 14:26:24 -0700133 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);
134 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);
135 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500136 busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);
Venki Pallipadiea487612007-06-20 14:26:24 -0700137
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700138 idle_time = cputime64_sub(cur_wall_time, busy_time);
139 if (wall)
Pallipadi, Venkatesh54c9a352009-11-11 16:50:29 -0800140 *wall = (cputime64_t)jiffies_to_usecs(cur_wall_time);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700141
Pallipadi, Venkatesh54c9a352009-11-11 16:50:29 -0800142 return (cputime64_t)jiffies_to_usecs(idle_time);
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700143}
144
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700145static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)
146{
147 u64 idle_time = get_cpu_idle_time_us(cpu, wall);
148
149 if (idle_time == -1ULL)
150 return get_cpu_idle_time_jiffy(cpu, wall);
151
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700152 return idle_time;
153}
154
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700155static inline cputime64_t get_cpu_iowait_time(unsigned int cpu, cputime64_t *wall)
156{
157 u64 iowait_time = get_cpu_iowait_time_us(cpu, wall);
158
159 if (iowait_time == -1ULL)
160 return 0;
161
162 return iowait_time;
163}
164
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400165/*
166 * Find right freq to be set now with powersave_bias on.
167 * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
168 * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
169 */
Adrian Bunkb5ecf602006-08-13 23:00:08 +0200170static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
171 unsigned int freq_next,
172 unsigned int relation)
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400173{
174 unsigned int freq_req, freq_reduc, freq_avg;
175 unsigned int freq_hi, freq_lo;
176 unsigned int index = 0;
177 unsigned int jiffies_total, jiffies_hi, jiffies_lo;
Tejun Heo245b2e72009-06-24 15:13:48 +0900178 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info,
179 policy->cpu);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400180
181 if (!dbs_info->freq_table) {
182 dbs_info->freq_lo = 0;
183 dbs_info->freq_lo_jiffies = 0;
184 return freq_next;
185 }
186
187 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
188 relation, &index);
189 freq_req = dbs_info->freq_table[index].frequency;
190 freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000;
191 freq_avg = freq_req - freq_reduc;
192
193 /* Find freq bounds for freq_avg in freq_table */
194 index = 0;
195 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
196 CPUFREQ_RELATION_H, &index);
197 freq_lo = dbs_info->freq_table[index].frequency;
198 index = 0;
199 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
200 CPUFREQ_RELATION_L, &index);
201 freq_hi = dbs_info->freq_table[index].frequency;
202
203 /* Find out how long we have to be in hi and lo freqs */
204 if (freq_hi == freq_lo) {
205 dbs_info->freq_lo = 0;
206 dbs_info->freq_lo_jiffies = 0;
207 return freq_lo;
208 }
209 jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
210 jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
211 jiffies_hi += ((freq_hi - freq_lo) / 2);
212 jiffies_hi /= (freq_hi - freq_lo);
213 jiffies_lo = jiffies_total - jiffies_hi;
214 dbs_info->freq_lo = freq_lo;
215 dbs_info->freq_lo_jiffies = jiffies_lo;
216 dbs_info->freq_hi_jiffies = jiffies_hi;
217 return freq_hi;
218}
219
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700220static void ondemand_powersave_bias_init_cpu(int cpu)
221{
Tejun Heo384be2b2009-08-14 14:41:02 +0900222 struct cpu_dbs_info_s *dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700223 dbs_info->freq_table = cpufreq_frequency_get_table(cpu);
224 dbs_info->freq_lo = 0;
225}
226
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400227static void ondemand_powersave_bias_init(void)
228{
229 int i;
230 for_each_online_cpu(i) {
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700231 ondemand_powersave_bias_init_cpu(i);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400232 }
233}
234
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235/************************** sysfs interface ************************/
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200236
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200237static ssize_t show_sampling_rate_min(struct kobject *kobj,
238 struct attribute *attr, char *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
Thomas Renningercef96152009-04-22 13:48:29 +0200240 return sprintf(buf, "%u\n", min_sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241}
242
Borislav Petkov6dad2a22010-03-31 21:56:46 +0200243define_one_global_ro(sampling_rate_min);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
245/* cpufreq_ondemand Governor Tunables */
246#define show_one(file_name, object) \
247static ssize_t show_##file_name \
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200248(struct kobject *kobj, struct attribute *attr, char *buf) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249{ \
250 return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
251}
252show_one(sampling_rate, sampling_rate);
Arjan van de Ven19379b12010-05-09 08:26:51 -0700253show_one(io_is_busy, io_is_busy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254show_one(up_threshold, up_threshold);
David C Niemi3f78a9f2010-10-06 16:54:24 -0400255show_one(sampling_down_factor, sampling_down_factor);
Alexander Clouter001893c2005-12-01 01:09:25 -0800256show_one(ignore_nice_load, ignore_nice);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400257show_one(powersave_bias, powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200259static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
260 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
262 unsigned int input;
263 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700264 ret = sscanf(buf, "%u", &input);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700265 if (ret != 1)
266 return -EINVAL;
Thomas Renningercef96152009-04-22 13:48:29 +0200267 dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 return count;
269}
270
Arjan van de Ven19379b12010-05-09 08:26:51 -0700271static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
272 const char *buf, size_t count)
273{
274 unsigned int input;
275 int ret;
276
277 ret = sscanf(buf, "%u", &input);
278 if (ret != 1)
279 return -EINVAL;
Arjan van de Ven19379b12010-05-09 08:26:51 -0700280 dbs_tuners_ins.io_is_busy = !!input;
Arjan van de Ven19379b12010-05-09 08:26:51 -0700281 return count;
282}
283
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200284static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
285 const char *buf, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286{
287 unsigned int input;
288 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700289 ret = sscanf(buf, "%u", &input);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
Dave Jones32ee8c32006-02-28 00:43:23 -0500291 if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
Dave Jonesc29f1402005-05-31 19:03:50 -0700292 input < MIN_FREQUENCY_UP_THRESHOLD) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 return -EINVAL;
294 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 dbs_tuners_ins.up_threshold = input;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 return count;
297}
298
David C Niemi3f78a9f2010-10-06 16:54:24 -0400299static ssize_t store_sampling_down_factor(struct kobject *a,
300 struct attribute *b, const char *buf, size_t count)
301{
302 unsigned int input, j;
303 int ret;
304 ret = sscanf(buf, "%u", &input);
305
306 if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
307 return -EINVAL;
David C Niemi3f78a9f2010-10-06 16:54:24 -0400308 dbs_tuners_ins.sampling_down_factor = input;
309
310 /* Reset down sampling multiplier in case it was active */
311 for_each_online_cpu(j) {
312 struct cpu_dbs_info_s *dbs_info;
313 dbs_info = &per_cpu(od_cpu_dbs_info, j);
314 dbs_info->rate_mult = 1;
315 }
David C Niemi3f78a9f2010-10-06 16:54:24 -0400316 return count;
317}
318
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200319static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
320 const char *buf, size_t count)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700321{
322 unsigned int input;
323 int ret;
324
325 unsigned int j;
Dave Jones32ee8c32006-02-28 00:43:23 -0500326
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700327 ret = sscanf(buf, "%u", &input);
Dave Jones2b03f892009-01-18 01:43:44 -0500328 if (ret != 1)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700329 return -EINVAL;
330
Dave Jones2b03f892009-01-18 01:43:44 -0500331 if (input > 1)
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700332 input = 1;
Dave Jones32ee8c32006-02-28 00:43:23 -0500333
Dave Jones2b03f892009-01-18 01:43:44 -0500334 if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700335 return count;
336 }
337 dbs_tuners_ins.ignore_nice = input;
338
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700339 /* we need to re-evaluate prev_cpu_idle */
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700340 for_each_online_cpu(j) {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700341 struct cpu_dbs_info_s *dbs_info;
Tejun Heo245b2e72009-06-24 15:13:48 +0900342 dbs_info = &per_cpu(od_cpu_dbs_info, j);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700343 dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
344 &dbs_info->prev_cpu_wall);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500345 if (dbs_tuners_ins.ignore_nice)
346 dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
347
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700348 }
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700349 return count;
350}
351
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200352static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
353 const char *buf, size_t count)
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400354{
355 unsigned int input;
356 int ret;
357 ret = sscanf(buf, "%u", &input);
358
359 if (ret != 1)
360 return -EINVAL;
361
362 if (input > 1000)
363 input = 1000;
364
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400365 dbs_tuners_ins.powersave_bias = input;
366 ondemand_powersave_bias_init();
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400367 return count;
368}
369
Borislav Petkov6dad2a22010-03-31 21:56:46 +0200370define_one_global_rw(sampling_rate);
Linus Torvalds07d77752010-05-18 08:49:13 -0700371define_one_global_rw(io_is_busy);
Borislav Petkov6dad2a22010-03-31 21:56:46 +0200372define_one_global_rw(up_threshold);
David C Niemi3f78a9f2010-10-06 16:54:24 -0400373define_one_global_rw(sampling_down_factor);
Borislav Petkov6dad2a22010-03-31 21:56:46 +0200374define_one_global_rw(ignore_nice_load);
375define_one_global_rw(powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
Dave Jones2b03f892009-01-18 01:43:44 -0500377static struct attribute *dbs_attributes[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 &sampling_rate_min.attr,
379 &sampling_rate.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 &up_threshold.attr,
David C Niemi3f78a9f2010-10-06 16:54:24 -0400381 &sampling_down_factor.attr,
Alexander Clouter001893c2005-12-01 01:09:25 -0800382 &ignore_nice_load.attr,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400383 &powersave_bias.attr,
Arjan van de Ven19379b12010-05-09 08:26:51 -0700384 &io_is_busy.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 NULL
386};
387
388static struct attribute_group dbs_attr_group = {
389 .attrs = dbs_attributes,
390 .name = "ondemand",
391};
392
393/************************** sysfs end ************************/
394
Mike Chan00e299f2010-01-26 17:06:47 -0800395static void dbs_freq_increase(struct cpufreq_policy *p, unsigned int freq)
396{
397 if (dbs_tuners_ins.powersave_bias)
398 freq = powersave_bias_target(p, freq, CPUFREQ_RELATION_H);
399 else if (p->cur == p->max)
400 return;
401
402 __cpufreq_driver_target(p, freq, dbs_tuners_ins.powersave_bias ?
403 CPUFREQ_RELATION_L : CPUFREQ_RELATION_H);
404}
405
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700406static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407{
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700408 unsigned int max_load_freq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
410 struct cpufreq_policy *policy;
411 unsigned int j;
412
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400413 this_dbs_info->freq_lo = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 policy = this_dbs_info->cur_policy;
Venki Pallipadiea487612007-06-20 14:26:24 -0700415
Dave Jones32ee8c32006-02-28 00:43:23 -0500416 /*
Dave Jonesc29f1402005-05-31 19:03:50 -0700417 * Every sampling_rate, we check, if current idle time is less
418 * than 20% (default), then we try to increase frequency
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700419 * Every sampling_rate, we look for a the lowest
Dave Jonesc29f1402005-05-31 19:03:50 -0700420 * frequency which can sustain the load while keeping idle time over
421 * 30%. If such a frequency exist, we try to decrease to this frequency.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 *
Dave Jones32ee8c32006-02-28 00:43:23 -0500423 * Any frequency increase takes it to the maximum frequency.
424 * Frequency reduction happens at minimum steps of
425 * 5% (default) of current frequency
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 */
427
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700428 /* Get Absolute Load - in terms of freq */
429 max_load_freq = 0;
430
Rusty Russell835481d2009-01-04 05:18:06 -0800431 for_each_cpu(j, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 struct cpu_dbs_info_s *j_dbs_info;
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700433 cputime64_t cur_wall_time, cur_idle_time, cur_iowait_time;
434 unsigned int idle_time, wall_time, iowait_time;
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700435 unsigned int load, load_freq;
436 int freq_avg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437
Tejun Heo245b2e72009-06-24 15:13:48 +0900438 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700439
440 cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700441 cur_iowait_time = get_cpu_iowait_time(j, &cur_wall_time);
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700442
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700443 wall_time = (unsigned int) cputime64_sub(cur_wall_time,
444 j_dbs_info->prev_cpu_wall);
445 j_dbs_info->prev_cpu_wall = cur_wall_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700447 idle_time = (unsigned int) cputime64_sub(cur_idle_time,
448 j_dbs_info->prev_cpu_idle);
449 j_dbs_info->prev_cpu_idle = cur_idle_time;
450
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700451 iowait_time = (unsigned int) cputime64_sub(cur_iowait_time,
452 j_dbs_info->prev_cpu_iowait);
453 j_dbs_info->prev_cpu_iowait = cur_iowait_time;
454
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500455 if (dbs_tuners_ins.ignore_nice) {
456 cputime64_t cur_nice;
457 unsigned long cur_nice_jiffies;
458
459 cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,
460 j_dbs_info->prev_cpu_nice);
461 /*
462 * Assumption: nice time between sampling periods will
463 * be less than 2^32 jiffies for 32 bit sys
464 */
465 cur_nice_jiffies = (unsigned long)
466 cputime64_to_jiffies64(cur_nice);
467
468 j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
469 idle_time += jiffies_to_usecs(cur_nice_jiffies);
470 }
471
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700472 /*
473 * For the purpose of ondemand, waiting for disk IO is an
474 * indication that you're performance critical, and not that
475 * the system is actually idle. So subtract the iowait time
476 * from the cpu idle time.
477 */
478
Arjan van de Ven19379b12010-05-09 08:26:51 -0700479 if (dbs_tuners_ins.io_is_busy && idle_time >= iowait_time)
Arjan van de Ven6b8fcd92010-05-09 08:26:06 -0700480 idle_time -= iowait_time;
481
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700482 if (unlikely(!wall_time || wall_time < idle_time))
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700483 continue;
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700484
485 load = 100 * (wall_time - idle_time) / wall_time;
486
487 freq_avg = __cpufreq_driver_getavg(policy, j);
488 if (freq_avg <= 0)
489 freq_avg = policy->cur;
490
491 load_freq = load * freq_avg;
492 if (load_freq > max_load_freq)
493 max_load_freq = load_freq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 }
495
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700496 /* Check for frequency increase */
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700497 if (max_load_freq > dbs_tuners_ins.up_threshold * policy->cur) {
David C Niemi3f78a9f2010-10-06 16:54:24 -0400498 /* If switching to max speed, apply sampling_down_factor */
499 if (policy->cur < policy->max)
500 this_dbs_info->rate_mult =
501 dbs_tuners_ins.sampling_down_factor;
Mike Chan00e299f2010-01-26 17:06:47 -0800502 dbs_freq_increase(policy, policy->max);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 return;
504 }
505
506 /* Check for frequency decrease */
Dave Jonesc29f1402005-05-31 19:03:50 -0700507 /* if we cannot reduce the frequency anymore, break out early */
508 if (policy->cur == policy->min)
509 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510
Dave Jonesc29f1402005-05-31 19:03:50 -0700511 /*
512 * The optimal frequency is the frequency that is the lowest that
513 * can support the current CPU usage without triggering the up
514 * policy. To be safe, we focus 10 points under the threshold.
515 */
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700516 if (max_load_freq <
517 (dbs_tuners_ins.up_threshold - dbs_tuners_ins.down_differential) *
518 policy->cur) {
venkatesh.pallipadi@intel.comc43aa3b2008-08-04 11:59:08 -0700519 unsigned int freq_next;
venkatesh.pallipadi@intel.come9d95bf2008-08-04 11:59:10 -0700520 freq_next = max_load_freq /
521 (dbs_tuners_ins.up_threshold -
522 dbs_tuners_ins.down_differential);
Venkatesh Pallipadidfde5d62006-10-03 12:38:45 -0700523
David C Niemi3f78a9f2010-10-06 16:54:24 -0400524 /* No longer fully busy, reset rate_mult */
525 this_dbs_info->rate_mult = 1;
526
Nagananda.Chumbalkar@hp.com1dbf5882009-12-21 23:40:52 +0100527 if (freq_next < policy->min)
528 freq_next = policy->min;
529
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400530 if (!dbs_tuners_ins.powersave_bias) {
531 __cpufreq_driver_target(policy, freq_next,
532 CPUFREQ_RELATION_L);
533 } else {
534 int freq = powersave_bias_target(policy, freq_next,
535 CPUFREQ_RELATION_L);
536 __cpufreq_driver_target(policy, freq,
537 CPUFREQ_RELATION_L);
538 }
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700539 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540}
541
David Howellsc4028952006-11-22 14:57:56 +0000542static void do_dbs_timer(struct work_struct *work)
Dave Jones32ee8c32006-02-28 00:43:23 -0500543{
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800544 struct cpu_dbs_info_s *dbs_info =
545 container_of(work, struct cpu_dbs_info_s, work.work);
546 unsigned int cpu = dbs_info->cpu;
547 int sample_type = dbs_info->sample_type;
548
Vincent Guittot5cb2c3b2011-02-07 17:14:25 +0100549 int delay;
Jocelyn Falempea665df92010-03-11 14:01:11 -0800550
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700551 mutex_lock(&dbs_info->timer_mutex);
Venkatesh Pallipadi56463b72007-02-05 16:12:45 -0800552
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400553 /* Common NORMAL_SAMPLE setup */
David Howellsc4028952006-11-22 14:57:56 +0000554 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400555 if (!dbs_tuners_ins.powersave_bias ||
David Howellsc4028952006-11-22 14:57:56 +0000556 sample_type == DBS_NORMAL_SAMPLE) {
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400557 dbs_check_cpu(dbs_info);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400558 if (dbs_info->freq_lo) {
559 /* Setup timer for SUB_SAMPLE */
David Howellsc4028952006-11-22 14:57:56 +0000560 dbs_info->sample_type = DBS_SUB_SAMPLE;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400561 delay = dbs_info->freq_hi_jiffies;
Vincent Guittot5cb2c3b2011-02-07 17:14:25 +0100562 } else {
563 /* We want all CPUs to do sampling nearly on
564 * same jiffy
565 */
566 delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate
567 * dbs_info->rate_mult);
568
569 if (num_online_cpus() > 1)
570 delay -= jiffies % delay;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400571 }
572 } else {
573 __cpufreq_driver_target(dbs_info->cur_policy,
Dave Jones2b03f892009-01-18 01:43:44 -0500574 dbs_info->freq_lo, CPUFREQ_RELATION_H);
Vincent Guittot5cb2c3b2011-02-07 17:14:25 +0100575 delay = dbs_info->freq_lo_jiffies;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400576 }
Tejun Heo57df5572011-01-26 12:12:50 +0100577 schedule_delayed_work_on(cpu, &dbs_info->work, delay);
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700578 mutex_unlock(&dbs_info->timer_mutex);
Dave Jones32ee8c32006-02-28 00:43:23 -0500579}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800581static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582{
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400583 /* We want all CPUs to do sampling nearly on same jiffy */
584 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
Jocelyn Falempea665df92010-03-11 14:01:11 -0800585
586 if (num_online_cpus() > 1)
587 delay -= jiffies % delay;
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700588
David Howellsc4028952006-11-22 14:57:56 +0000589 dbs_info->sample_type = DBS_NORMAL_SAMPLE;
Venki Pallipadi28287032007-05-08 00:27:47 -0700590 INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
Tejun Heo57df5572011-01-26 12:12:50 +0100591 schedule_delayed_work_on(dbs_info->cpu, &dbs_info->work, delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592}
593
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700594static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
Mathieu Desnoyersb14893a2009-05-17 10:30:45 -0400596 cancel_delayed_work_sync(&dbs_info->work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597}
598
Arjan van de Ven19379b12010-05-09 08:26:51 -0700599/*
600 * Not all CPUs want IO time to be accounted as busy; this dependson how
601 * efficient idling at a higher frequency/voltage is.
602 * Pavel Machek says this is not so for various generations of AMD and old
603 * Intel systems.
604 * Mike Chan (androidlcom) calis this is also not true for ARM.
605 * Because of this, whitelist specific known (series) of CPUs by default, and
606 * leave all others up to the user.
607 */
608static int should_io_be_busy(void)
609{
610#if defined(CONFIG_X86)
611 /*
612 * For Intel, Core 2 (model 15) andl later have an efficient idle.
613 */
614 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
615 boot_cpu_data.x86 == 6 &&
616 boot_cpu_data.x86_model >= 15)
617 return 1;
618#endif
619 return 0;
620}
621
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
623 unsigned int event)
624{
625 unsigned int cpu = policy->cpu;
626 struct cpu_dbs_info_s *this_dbs_info;
627 unsigned int j;
Jeff Garzik914f7c32006-10-20 14:31:00 -0700628 int rc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
Tejun Heo245b2e72009-06-24 15:13:48 +0900630 this_dbs_info = &per_cpu(od_cpu_dbs_info, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631
632 switch (event) {
633 case CPUFREQ_GOV_START:
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700634 if ((!cpu_online(cpu)) || (!policy->cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 return -EINVAL;
636
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800637 mutex_lock(&dbs_mutex);
Jeff Garzik914f7c32006-10-20 14:31:00 -0700638
venkatesh.pallipadi@intel.com5a75c822009-07-02 17:08:32 -0700639 dbs_enable++;
Rusty Russell835481d2009-01-04 05:18:06 -0800640 for_each_cpu(j, policy->cpus) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 struct cpu_dbs_info_s *j_dbs_info;
Tejun Heo245b2e72009-06-24 15:13:48 +0900642 j_dbs_info = &per_cpu(od_cpu_dbs_info, j);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 j_dbs_info->cur_policy = policy;
Dave Jones32ee8c32006-02-28 00:43:23 -0500644
venkatesh.pallipadi@intel.com34305022008-08-04 11:59:09 -0700645 j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,
646 &j_dbs_info->prev_cpu_wall);
Venkatesh Pallipadi1ca3abd2009-01-23 09:25:02 -0500647 if (dbs_tuners_ins.ignore_nice) {
648 j_dbs_info->prev_cpu_nice =
649 kstat_cpu(j).cpustat.nice;
650 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 }
Venkatesh Pallipadi529af7a2007-02-05 16:12:44 -0800652 this_dbs_info->cpu = cpu;
David C Niemi3f78a9f2010-10-06 16:54:24 -0400653 this_dbs_info->rate_mult = 1;
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);
Arjan van de Ven19379b12010-05-09 08:26:51 -0700679 dbs_tuners_ins.io_is_busy = should_io_be_busy();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 }
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800681 mutex_unlock(&dbs_mutex);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700682
Thomas Renninger0e625ac2009-07-24 15:25:06 +0200683 mutex_init(&this_dbs_info->timer_mutex);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700684 dbs_timer_init(this_dbs_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 break;
686
687 case CPUFREQ_GOV_STOP:
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700688 dbs_timer_exit(this_dbs_info);
venkatesh.pallipadi@intel.com7d26e2d2009-07-02 17:08:30 -0700689
690 mutex_lock(&dbs_mutex);
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{
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700716 cputime64_t wall;
Andrea Righi4f6e6b92008-09-18 10:43:40 +0000717 u64 idle_time;
718 int cpu = get_cpu();
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700719
Andrea Righi4f6e6b92008-09-18 10:43:40 +0000720 idle_time = get_cpu_idle_time_us(cpu, &wall);
721 put_cpu();
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700722 if (idle_time != -1ULL) {
723 /* Idle micro accounting is supported. Use finer thresholds */
724 dbs_tuners_ins.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
725 dbs_tuners_ins.down_differential =
726 MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
Thomas Renningercef96152009-04-22 13:48:29 +0200727 /*
Paul Bollebd74b322011-08-06 14:33:43 +0200728 * In nohz/micro accounting case we set the minimum frequency
Thomas Renningercef96152009-04-22 13:48:29 +0200729 * not depending on HZ, but fixed (very low). The deferred
730 * timer might skip some samples if idle/sleeping as needed.
731 */
732 min_sampling_rate = MICRO_FREQUENCY_MIN_SAMPLE_RATE;
733 } else {
734 /* For correct statistics, we need 10 ticks for each measure */
735 min_sampling_rate =
736 MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10);
venkatesh.pallipadi@intel.com80800912008-08-04 11:59:12 -0700737 }
Akinobu Mita888a7942008-07-14 12:00:45 +0900738
Tejun Heo57df5572011-01-26 12:12:50 +0100739 return cpufreq_register_governor(&cpufreq_gov_ondemand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740}
741
742static void __exit cpufreq_gov_dbs_exit(void)
743{
Thomas Renninger1c256242007-10-02 13:28:12 -0700744 cpufreq_unregister_governor(&cpufreq_gov_ondemand);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745}
746
747
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700748MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
749MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
750MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
Dave Jones2b03f892009-01-18 01:43:44 -0500751 "Low Latency Frequency Transition capable processors");
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700752MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753
Johannes Weiner69157192008-01-17 15:21:08 -0800754#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
755fs_initcall(cpufreq_gov_dbs_init);
756#else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757module_init(cpufreq_gov_dbs_init);
Johannes Weiner69157192008-01-17 15:21:08 -0800758#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759module_exit(cpufreq_gov_dbs_exit);