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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
22/*
23 * dbs is used in this file as a shortform for demandbased switching
24 * It helps to keep variable names smaller, simpler
25 */
26
27#define DEF_FREQUENCY_UP_THRESHOLD (80)
Dave Jonesc29f1402005-05-31 19:03:50 -070028#define MIN_FREQUENCY_UP_THRESHOLD (11)
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#define MAX_FREQUENCY_UP_THRESHOLD (100)
30
Dave Jones32ee8c32006-02-28 00:43:23 -050031/*
32 * The polling frequency of this governor depends on the capability of
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 * the processor. Default polling frequency is 1000 times the transition
Dave Jones32ee8c32006-02-28 00:43:23 -050034 * latency of the processor. The governor will work on any processor with
35 * transition latency <= 10mS, using appropriate sampling
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 * rate.
37 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)
38 * this governor will not work.
39 * All times here are in uS.
40 */
Dave Jones32ee8c32006-02-28 00:43:23 -050041static unsigned int def_sampling_rate;
Dave Jonesdf8b59b2005-09-20 12:39:35 -070042#define MIN_SAMPLING_RATE_RATIO (2)
43/* for correct statistics, we need at least 10 ticks between each measure */
44#define MIN_STAT_SAMPLING_RATE (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
45#define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#define MAX_SAMPLING_RATE (500 * def_sampling_rate)
47#define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070048#define TRANSITION_LATENCY_LIMIT (10 * 1000)
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50static void do_dbs_timer(void *data);
51
52struct cpu_dbs_info_s {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070053 cputime64_t prev_cpu_idle;
54 cputime64_t prev_cpu_wall;
Dave Jones32ee8c32006-02-28 00:43:23 -050055 struct cpufreq_policy *cur_policy;
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -070056 struct work_struct work;
Dave Jones32ee8c32006-02-28 00:43:23 -050057 unsigned int enable;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040058 struct cpufreq_frequency_table *freq_table;
59 unsigned int freq_lo;
60 unsigned int freq_lo_jiffies;
61 unsigned int freq_hi_jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062};
63static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
64
65static unsigned int dbs_enable; /* number of CPUs using this policy */
66
Venkatesh Pallipadi4ec223d2006-06-21 15:18:34 -070067/*
68 * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
69 * lock and dbs_mutex. cpu_hotplug lock should always be held before
70 * dbs_mutex. If any function that can potentially take cpu_hotplug lock
71 * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
72 * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
73 * is recursive for the same process. -Venki
74 */
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -070075static DEFINE_MUTEX(dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -070077static struct workqueue_struct *kondemand_wq;
Andi Kleen6810b542006-05-08 15:17:31 +020078
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040079static struct dbs_tuners {
Dave Jones32ee8c32006-02-28 00:43:23 -050080 unsigned int sampling_rate;
Dave Jones32ee8c32006-02-28 00:43:23 -050081 unsigned int up_threshold;
82 unsigned int ignore_nice;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040083 unsigned int powersave_bias;
84} dbs_tuners_ins = {
Dave Jones32ee8c32006-02-28 00:43:23 -050085 .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
Eric Piel9cbad612006-03-10 11:35:27 +020086 .ignore_nice = 0,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +040087 .powersave_bias = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -070088};
89
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070090static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
Dave Jonesdac1c1a2005-05-31 19:03:49 -070091{
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -070092 cputime64_t retval;
93
94 retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
95 kstat_cpu(cpu).cpustat.iowait);
96
97 if (dbs_tuners_ins.ignore_nice)
98 retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
99
100 return retval;
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700101}
102
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400103/*
104 * Find right freq to be set now with powersave_bias on.
105 * Returns the freq_hi to be used right now and will set freq_hi_jiffies,
106 * freq_lo, and freq_lo_jiffies in percpu area for averaging freqs.
107 */
Adrian Bunkb5ecf602006-08-13 23:00:08 +0200108static unsigned int powersave_bias_target(struct cpufreq_policy *policy,
109 unsigned int freq_next,
110 unsigned int relation)
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400111{
112 unsigned int freq_req, freq_reduc, freq_avg;
113 unsigned int freq_hi, freq_lo;
114 unsigned int index = 0;
115 unsigned int jiffies_total, jiffies_hi, jiffies_lo;
116 struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, policy->cpu);
117
118 if (!dbs_info->freq_table) {
119 dbs_info->freq_lo = 0;
120 dbs_info->freq_lo_jiffies = 0;
121 return freq_next;
122 }
123
124 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_next,
125 relation, &index);
126 freq_req = dbs_info->freq_table[index].frequency;
127 freq_reduc = freq_req * dbs_tuners_ins.powersave_bias / 1000;
128 freq_avg = freq_req - freq_reduc;
129
130 /* Find freq bounds for freq_avg in freq_table */
131 index = 0;
132 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
133 CPUFREQ_RELATION_H, &index);
134 freq_lo = dbs_info->freq_table[index].frequency;
135 index = 0;
136 cpufreq_frequency_table_target(policy, dbs_info->freq_table, freq_avg,
137 CPUFREQ_RELATION_L, &index);
138 freq_hi = dbs_info->freq_table[index].frequency;
139
140 /* Find out how long we have to be in hi and lo freqs */
141 if (freq_hi == freq_lo) {
142 dbs_info->freq_lo = 0;
143 dbs_info->freq_lo_jiffies = 0;
144 return freq_lo;
145 }
146 jiffies_total = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
147 jiffies_hi = (freq_avg - freq_lo) * jiffies_total;
148 jiffies_hi += ((freq_hi - freq_lo) / 2);
149 jiffies_hi /= (freq_hi - freq_lo);
150 jiffies_lo = jiffies_total - jiffies_hi;
151 dbs_info->freq_lo = freq_lo;
152 dbs_info->freq_lo_jiffies = jiffies_lo;
153 dbs_info->freq_hi_jiffies = jiffies_hi;
154 return freq_hi;
155}
156
157static void ondemand_powersave_bias_init(void)
158{
159 int i;
160 for_each_online_cpu(i) {
161 struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, i);
162 dbs_info->freq_table = cpufreq_frequency_get_table(i);
163 dbs_info->freq_lo = 0;
164 }
165}
166
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167/************************** sysfs interface ************************/
168static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
169{
170 return sprintf (buf, "%u\n", MAX_SAMPLING_RATE);
171}
172
173static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
174{
175 return sprintf (buf, "%u\n", MIN_SAMPLING_RATE);
176}
177
Dave Jones32ee8c32006-02-28 00:43:23 -0500178#define define_one_ro(_name) \
179static struct freq_attr _name = \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180__ATTR(_name, 0444, show_##_name, NULL)
181
182define_one_ro(sampling_rate_max);
183define_one_ro(sampling_rate_min);
184
185/* cpufreq_ondemand Governor Tunables */
186#define show_one(file_name, object) \
187static ssize_t show_##file_name \
188(struct cpufreq_policy *unused, char *buf) \
189{ \
190 return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
191}
192show_one(sampling_rate, sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193show_one(up_threshold, up_threshold);
Alexander Clouter001893c2005-12-01 01:09:25 -0800194show_one(ignore_nice_load, ignore_nice);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400195show_one(powersave_bias, powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196
Dave Jones32ee8c32006-02-28 00:43:23 -0500197static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 const char *buf, size_t count)
199{
200 unsigned int input;
201 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700202 ret = sscanf(buf, "%u", &input);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800204 mutex_lock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205 if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800206 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 return -EINVAL;
208 }
209
210 dbs_tuners_ins.sampling_rate = input;
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800211 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212
213 return count;
214}
215
Dave Jones32ee8c32006-02-28 00:43:23 -0500216static ssize_t store_up_threshold(struct cpufreq_policy *unused,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 const char *buf, size_t count)
218{
219 unsigned int input;
220 int ret;
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700221 ret = sscanf(buf, "%u", &input);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800223 mutex_lock(&dbs_mutex);
Dave Jones32ee8c32006-02-28 00:43:23 -0500224 if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
Dave Jonesc29f1402005-05-31 19:03:50 -0700225 input < MIN_FREQUENCY_UP_THRESHOLD) {
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800226 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 return -EINVAL;
228 }
229
230 dbs_tuners_ins.up_threshold = input;
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800231 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
233 return count;
234}
235
Alexander Clouter001893c2005-12-01 01:09:25 -0800236static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700237 const char *buf, size_t count)
238{
239 unsigned int input;
240 int ret;
241
242 unsigned int j;
Dave Jones32ee8c32006-02-28 00:43:23 -0500243
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700244 ret = sscanf(buf, "%u", &input);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700245 if ( ret != 1 )
246 return -EINVAL;
247
248 if ( input > 1 )
249 input = 1;
Dave Jones32ee8c32006-02-28 00:43:23 -0500250
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800251 mutex_lock(&dbs_mutex);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700252 if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800253 mutex_unlock(&dbs_mutex);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700254 return count;
255 }
256 dbs_tuners_ins.ignore_nice = input;
257
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700258 /* we need to re-evaluate prev_cpu_idle */
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700259 for_each_online_cpu(j) {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700260 struct cpu_dbs_info_s *dbs_info;
261 dbs_info = &per_cpu(cpu_dbs_info, j);
262 dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
263 dbs_info->prev_cpu_wall = get_jiffies_64();
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700264 }
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800265 mutex_unlock(&dbs_mutex);
Dave Jones3d5ee9e2005-05-31 19:03:47 -0700266
267 return count;
268}
269
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400270static ssize_t store_powersave_bias(struct cpufreq_policy *unused,
271 const char *buf, size_t count)
272{
273 unsigned int input;
274 int ret;
275 ret = sscanf(buf, "%u", &input);
276
277 if (ret != 1)
278 return -EINVAL;
279
280 if (input > 1000)
281 input = 1000;
282
283 mutex_lock(&dbs_mutex);
284 dbs_tuners_ins.powersave_bias = input;
285 ondemand_powersave_bias_init();
286 mutex_unlock(&dbs_mutex);
287
288 return count;
289}
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291#define define_one_rw(_name) \
292static struct freq_attr _name = \
293__ATTR(_name, 0644, show_##_name, store_##_name)
294
295define_one_rw(sampling_rate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296define_one_rw(up_threshold);
Alexander Clouter001893c2005-12-01 01:09:25 -0800297define_one_rw(ignore_nice_load);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400298define_one_rw(powersave_bias);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
300static struct attribute * dbs_attributes[] = {
301 &sampling_rate_max.attr,
302 &sampling_rate_min.attr,
303 &sampling_rate.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 &up_threshold.attr,
Alexander Clouter001893c2005-12-01 01:09:25 -0800305 &ignore_nice_load.attr,
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400306 &powersave_bias.attr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 NULL
308};
309
310static struct attribute_group dbs_attr_group = {
311 .attrs = dbs_attributes,
312 .name = "ondemand",
313};
314
315/************************** sysfs end ************************/
316
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700317static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318{
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700319 unsigned int idle_ticks, total_ticks;
320 unsigned int load;
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700321 cputime64_t cur_jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
323 struct cpufreq_policy *policy;
324 unsigned int j;
325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 if (!this_dbs_info->enable)
327 return;
328
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400329 this_dbs_info->freq_lo = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 policy = this_dbs_info->cur_policy;
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700331 cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
332 total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
333 this_dbs_info->prev_cpu_wall);
334 this_dbs_info->prev_cpu_wall = cur_jiffies;
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700335 if (!total_ticks)
336 return;
Dave Jones32ee8c32006-02-28 00:43:23 -0500337 /*
Dave Jonesc29f1402005-05-31 19:03:50 -0700338 * Every sampling_rate, we check, if current idle time is less
339 * than 20% (default), then we try to increase frequency
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700340 * Every sampling_rate, we look for a the lowest
Dave Jonesc29f1402005-05-31 19:03:50 -0700341 * frequency which can sustain the load while keeping idle time over
342 * 30%. If such a frequency exist, we try to decrease to this frequency.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 *
Dave Jones32ee8c32006-02-28 00:43:23 -0500344 * Any frequency increase takes it to the maximum frequency.
345 * Frequency reduction happens at minimum steps of
346 * 5% (default) of current frequency
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 */
348
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700349 /* Get Idle Time */
Dave Jones9c7d2692005-05-31 19:03:49 -0700350 idle_ticks = UINT_MAX;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 for_each_cpu_mask(j, policy->cpus) {
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700352 cputime64_t total_idle_ticks;
353 unsigned int tmp_idle_ticks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 struct cpu_dbs_info_s *j_dbs_info;
355
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 j_dbs_info = &per_cpu(cpu_dbs_info, j);
Dave Jonesdac1c1a2005-05-31 19:03:49 -0700357 total_idle_ticks = get_cpu_idle_time(j);
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700358 tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
359 j_dbs_info->prev_cpu_idle);
360 j_dbs_info->prev_cpu_idle = total_idle_ticks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361
362 if (tmp_idle_ticks < idle_ticks)
363 idle_ticks = tmp_idle_ticks;
364 }
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700365 load = (100 * (total_ticks - idle_ticks)) / total_ticks;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700367 /* Check for frequency increase */
368 if (load > dbs_tuners_ins.up_threshold) {
Dave Jonesc11420a2005-05-31 19:03:48 -0700369 /* if we are already at full speed then break out early */
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400370 if (!dbs_tuners_ins.powersave_bias) {
371 if (policy->cur == policy->max)
372 return;
Dave Jones32ee8c32006-02-28 00:43:23 -0500373
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400374 __cpufreq_driver_target(policy, policy->max,
375 CPUFREQ_RELATION_H);
376 } else {
377 int freq = powersave_bias_target(policy, policy->max,
378 CPUFREQ_RELATION_H);
379 __cpufreq_driver_target(policy, freq,
380 CPUFREQ_RELATION_L);
381 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 return;
383 }
384
385 /* Check for frequency decrease */
Dave Jonesc29f1402005-05-31 19:03:50 -0700386 /* if we cannot reduce the frequency anymore, break out early */
387 if (policy->cur == policy->min)
388 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389
Dave Jonesc29f1402005-05-31 19:03:50 -0700390 /*
391 * The optimal frequency is the frequency that is the lowest that
392 * can support the current CPU usage without triggering the up
393 * policy. To be safe, we focus 10 points under the threshold.
394 */
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700395 if (load < (dbs_tuners_ins.up_threshold - 10)) {
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400396 unsigned int freq_next = (policy->cur * load) /
Dave Jonesc29f1402005-05-31 19:03:50 -0700397 (dbs_tuners_ins.up_threshold - 10);
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400398 if (!dbs_tuners_ins.powersave_bias) {
399 __cpufreq_driver_target(policy, freq_next,
400 CPUFREQ_RELATION_L);
401 } else {
402 int freq = powersave_bias_target(policy, freq_next,
403 CPUFREQ_RELATION_L);
404 __cpufreq_driver_target(policy, freq,
405 CPUFREQ_RELATION_L);
406 }
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700407 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408}
409
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400410/* Sampling types */
411enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
412
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413static void do_dbs_timer(void *data)
Dave Jones32ee8c32006-02-28 00:43:23 -0500414{
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700415 unsigned int cpu = smp_processor_id();
416 struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400417 /* We want all CPUs to do sampling nearly on same jiffy */
418 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
419 delay -= jiffies % delay;
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700420
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700421 if (!dbs_info->enable)
422 return;
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400423 /* Common NORMAL_SAMPLE setup */
424 INIT_WORK(&dbs_info->work, do_dbs_timer, (void *)DBS_NORMAL_SAMPLE);
425 if (!dbs_tuners_ins.powersave_bias ||
426 (unsigned long) data == DBS_NORMAL_SAMPLE) {
427 lock_cpu_hotplug();
428 dbs_check_cpu(dbs_info);
429 unlock_cpu_hotplug();
430 if (dbs_info->freq_lo) {
431 /* Setup timer for SUB_SAMPLE */
432 INIT_WORK(&dbs_info->work, do_dbs_timer,
433 (void *)DBS_SUB_SAMPLE);
434 delay = dbs_info->freq_hi_jiffies;
435 }
436 } else {
437 __cpufreq_driver_target(dbs_info->cur_policy,
438 dbs_info->freq_lo,
439 CPUFREQ_RELATION_H);
440 }
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400441 queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
Dave Jones32ee8c32006-02-28 00:43:23 -0500442}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700444static inline void dbs_timer_init(unsigned int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445{
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700446 struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400447 /* We want all CPUs to do sampling nearly on same jiffy */
448 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
449 delay -= jiffies % delay;
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700450
Alexey Starikovskiy05ca0352006-07-31 22:28:12 +0400451 ondemand_powersave_bias_init();
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700452 INIT_WORK(&dbs_info->work, do_dbs_timer, 0);
Alexey Starikovskiy1ce28d62006-07-31 22:25:20 +0400453 queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work, delay);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454}
455
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700456static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457{
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700458 dbs_info->enable = 0;
459 cancel_delayed_work(&dbs_info->work);
460 flush_workqueue(kondemand_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461}
462
463static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
464 unsigned int event)
465{
466 unsigned int cpu = policy->cpu;
467 struct cpu_dbs_info_s *this_dbs_info;
468 unsigned int j;
469
470 this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
471
472 switch (event) {
473 case CPUFREQ_GOV_START:
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700474 if ((!cpu_online(cpu)) || (!policy->cur))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 return -EINVAL;
476
477 if (policy->cpuinfo.transition_latency >
Eric Pielff8c2882006-03-10 11:34:16 +0200478 (TRANSITION_LATENCY_LIMIT * 1000)) {
479 printk(KERN_WARNING "ondemand governor failed to load "
480 "due to too long transition latency\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 return -EINVAL;
Eric Pielff8c2882006-03-10 11:34:16 +0200482 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 if (this_dbs_info->enable) /* Already enabled */
484 break;
Dave Jones32ee8c32006-02-28 00:43:23 -0500485
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800486 mutex_lock(&dbs_mutex);
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700487 dbs_enable++;
488 if (dbs_enable == 1) {
489 kondemand_wq = create_workqueue("kondemand");
490 if (!kondemand_wq) {
491 printk(KERN_ERR "Creation of kondemand failed\n");
492 dbs_enable--;
493 mutex_unlock(&dbs_mutex);
494 return -ENOSPC;
495 }
496 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 for_each_cpu_mask(j, policy->cpus) {
498 struct cpu_dbs_info_s *j_dbs_info;
499 j_dbs_info = &per_cpu(cpu_dbs_info, j);
500 j_dbs_info->cur_policy = policy;
Dave Jones32ee8c32006-02-28 00:43:23 -0500501
Venkatesh Pallipadiccb2fe22006-06-28 13:49:52 -0700502 j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j);
503 j_dbs_info->prev_cpu_wall = get_jiffies_64();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 }
505 this_dbs_info->enable = 1;
506 sysfs_create_group(&policy->kobj, &dbs_attr_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 /*
508 * Start the timerschedule work, when this governor
509 * is used for first time
510 */
511 if (dbs_enable == 1) {
512 unsigned int latency;
513 /* policy latency is in nS. Convert it to uS first */
Dave Jonesdf8b59b2005-09-20 12:39:35 -0700514 latency = policy->cpuinfo.transition_latency / 1000;
515 if (latency == 0)
516 latency = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517
Dave Jonesdf8b59b2005-09-20 12:39:35 -0700518 def_sampling_rate = latency *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
Dave Jonesdf8b59b2005-09-20 12:39:35 -0700520
521 if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
522 def_sampling_rate = MIN_STAT_SAMPLING_RATE;
523
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 dbs_tuners_ins.sampling_rate = def_sampling_rate;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 }
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700526 dbs_timer_init(policy->cpu);
Dave Jones32ee8c32006-02-28 00:43:23 -0500527
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800528 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 break;
530
531 case CPUFREQ_GOV_STOP:
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800532 mutex_lock(&dbs_mutex);
Linus Torvalds2cd7cbd2006-07-23 12:05:00 -0700533 dbs_timer_exit(this_dbs_info);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 sysfs_remove_group(&policy->kobj, &dbs_attr_group);
535 dbs_enable--;
Dave Jones32ee8c32006-02-28 00:43:23 -0500536 if (dbs_enable == 0)
Venkatesh Pallipadi2f8a8352006-06-28 13:51:19 -0700537 destroy_workqueue(kondemand_wq);
Dave Jones32ee8c32006-02-28 00:43:23 -0500538
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800539 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
541 break;
542
543 case CPUFREQ_GOV_LIMITS:
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800544 mutex_lock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 if (policy->max < this_dbs_info->cur_policy->cur)
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700546 __cpufreq_driver_target(this_dbs_info->cur_policy,
547 policy->max,
548 CPUFREQ_RELATION_H);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 else if (policy->min > this_dbs_info->cur_policy->cur)
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700550 __cpufreq_driver_target(this_dbs_info->cur_policy,
551 policy->min,
552 CPUFREQ_RELATION_L);
akpm@osdl.org3fc54d32006-01-13 15:54:22 -0800553 mutex_unlock(&dbs_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 break;
555 }
556 return 0;
557}
558
Dave Jones7f335d42005-05-31 19:03:46 -0700559static struct cpufreq_governor cpufreq_gov_dbs = {
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700560 .name = "ondemand",
561 .governor = cpufreq_governor_dbs,
562 .owner = THIS_MODULE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565static int __init cpufreq_gov_dbs_init(void)
566{
567 return cpufreq_register_governor(&cpufreq_gov_dbs);
568}
569
570static void __exit cpufreq_gov_dbs_exit(void)
571{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 cpufreq_unregister_governor(&cpufreq_gov_dbs);
573}
574
575
Venkatesh Pallipadiffac80e2006-06-28 13:52:18 -0700576MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
577MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
578MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
579 "Low Latency Frequency Transition capable processors");
580MODULE_LICENSE("GPL");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
582module_init(cpufreq_gov_dbs_init);
583module_exit(cpufreq_gov_dbs_exit);