2 * drivers/cpufreq/cpufreq_conservative.c
4 * Copyright (C) 2001 Russell King
5 * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
6 * Jun Nakajima <jun.nakajima@intel.com>
7 * (C) 2009 Alexander Clouter <alex@digriz.org.uk>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/slab.h>
15 #include "cpufreq_governor.h"
17 /* Conservative governor macros */
18 #define DEF_FREQUENCY_UP_THRESHOLD (80)
19 #define DEF_FREQUENCY_DOWN_THRESHOLD (20)
20 #define DEF_FREQUENCY_STEP (5)
21 #define DEF_SAMPLING_DOWN_FACTOR (1)
22 #define MAX_SAMPLING_DOWN_FACTOR (10)
24 static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s
, cs_cpu_dbs_info
);
26 static int cs_cpufreq_governor_dbs(struct cpufreq_policy
*policy
,
29 static struct cpufreq_governor cpufreq_gov_conservative
= {
30 .name
= "conservative",
31 .governor
= cs_cpufreq_governor_dbs
,
32 .max_transition_latency
= TRANSITION_LATENCY_LIMIT
,
36 static inline unsigned int get_freq_target(struct cs_dbs_tuners
*cs_tuners
,
37 struct cpufreq_policy
*policy
)
39 unsigned int freq_target
= (cs_tuners
->freq_step
* policy
->max
) / 100;
41 /* max freq cannot be less than 100. But who knows... */
42 if (unlikely(freq_target
== 0))
43 freq_target
= DEF_FREQUENCY_STEP
;
49 * Every sampling_rate, we check, if current idle time is less than 20%
50 * (default), then we try to increase frequency. Every sampling_rate *
51 * sampling_down_factor, we check, if current idle time is more than 80%
52 * (default), then we try to decrease frequency
54 * Any frequency increase takes it to the maximum frequency. Frequency reduction
55 * happens at minimum steps of 5% (default) of maximum frequency
57 static void cs_check_cpu(int cpu
, unsigned int load
)
59 struct cs_cpu_dbs_info_s
*dbs_info
= &per_cpu(cs_cpu_dbs_info
, cpu
);
60 struct cpufreq_policy
*policy
= dbs_info
->cdbs
.shared
->policy
;
61 struct dbs_data
*dbs_data
= policy
->governor_data
;
62 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
65 * break out if we 'cannot' reduce the speed as the user might
66 * want freq_step to be zero
68 if (cs_tuners
->freq_step
== 0)
71 /* Check for frequency increase */
72 if (load
> cs_tuners
->up_threshold
) {
73 dbs_info
->down_skip
= 0;
75 /* if we are already at full speed then break out early */
76 if (dbs_info
->requested_freq
== policy
->max
)
79 dbs_info
->requested_freq
+= get_freq_target(cs_tuners
, policy
);
81 if (dbs_info
->requested_freq
> policy
->max
)
82 dbs_info
->requested_freq
= policy
->max
;
84 __cpufreq_driver_target(policy
, dbs_info
->requested_freq
,
89 /* if sampling_down_factor is active break out early */
90 if (++dbs_info
->down_skip
< cs_tuners
->sampling_down_factor
)
92 dbs_info
->down_skip
= 0;
94 /* Check for frequency decrease */
95 if (load
< cs_tuners
->down_threshold
) {
96 unsigned int freq_target
;
98 * if we cannot reduce the frequency anymore, break out early
100 if (policy
->cur
== policy
->min
)
103 freq_target
= get_freq_target(cs_tuners
, policy
);
104 if (dbs_info
->requested_freq
> freq_target
)
105 dbs_info
->requested_freq
-= freq_target
;
107 dbs_info
->requested_freq
= policy
->min
;
109 __cpufreq_driver_target(policy
, dbs_info
->requested_freq
,
115 static unsigned int cs_dbs_timer(struct cpufreq_policy
*policy
)
117 struct dbs_data
*dbs_data
= policy
->governor_data
;
118 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
120 dbs_check_cpu(dbs_data
, policy
->cpu
);
121 return delay_for_sampling_rate(cs_tuners
->sampling_rate
);
124 static int dbs_cpufreq_notifier(struct notifier_block
*nb
, unsigned long val
,
127 struct cpufreq_freqs
*freq
= data
;
128 struct cs_cpu_dbs_info_s
*dbs_info
=
129 &per_cpu(cs_cpu_dbs_info
, freq
->cpu
);
130 struct cpufreq_policy
*policy
= cpufreq_cpu_get_raw(freq
->cpu
);
135 /* policy isn't governed by conservative governor */
136 if (policy
->governor
!= &cpufreq_gov_conservative
)
140 * we only care if our internally tracked freq moves outside the 'valid'
141 * ranges of frequency available to us otherwise we do not change it
143 if (dbs_info
->requested_freq
> policy
->max
144 || dbs_info
->requested_freq
< policy
->min
)
145 dbs_info
->requested_freq
= freq
->new;
150 static struct notifier_block cs_cpufreq_notifier_block
= {
151 .notifier_call
= dbs_cpufreq_notifier
,
154 /************************** sysfs interface ************************/
155 static struct common_dbs_data cs_dbs_cdata
;
157 static ssize_t
store_sampling_down_factor(struct dbs_data
*dbs_data
,
158 const char *buf
, size_t count
)
160 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
163 ret
= sscanf(buf
, "%u", &input
);
165 if (ret
!= 1 || input
> MAX_SAMPLING_DOWN_FACTOR
|| input
< 1)
168 cs_tuners
->sampling_down_factor
= input
;
172 static ssize_t
store_sampling_rate(struct dbs_data
*dbs_data
, const char *buf
,
175 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
178 ret
= sscanf(buf
, "%u", &input
);
183 cs_tuners
->sampling_rate
= max(input
, dbs_data
->min_sampling_rate
);
187 static ssize_t
store_up_threshold(struct dbs_data
*dbs_data
, const char *buf
,
190 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
193 ret
= sscanf(buf
, "%u", &input
);
195 if (ret
!= 1 || input
> 100 || input
<= cs_tuners
->down_threshold
)
198 cs_tuners
->up_threshold
= input
;
202 static ssize_t
store_down_threshold(struct dbs_data
*dbs_data
, const char *buf
,
205 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
208 ret
= sscanf(buf
, "%u", &input
);
210 /* cannot be lower than 11 otherwise freq will not fall */
211 if (ret
!= 1 || input
< 11 || input
> 100 ||
212 input
>= cs_tuners
->up_threshold
)
215 cs_tuners
->down_threshold
= input
;
219 static ssize_t
store_ignore_nice_load(struct dbs_data
*dbs_data
,
220 const char *buf
, size_t count
)
222 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
223 unsigned int input
, j
;
226 ret
= sscanf(buf
, "%u", &input
);
233 if (input
== cs_tuners
->ignore_nice_load
) /* nothing to do */
236 cs_tuners
->ignore_nice_load
= input
;
238 /* we need to re-evaluate prev_cpu_idle */
239 for_each_online_cpu(j
) {
240 struct cs_cpu_dbs_info_s
*dbs_info
;
241 dbs_info
= &per_cpu(cs_cpu_dbs_info
, j
);
242 dbs_info
->cdbs
.prev_cpu_idle
= get_cpu_idle_time(j
,
243 &dbs_info
->cdbs
.prev_cpu_wall
, 0);
244 if (cs_tuners
->ignore_nice_load
)
245 dbs_info
->cdbs
.prev_cpu_nice
=
246 kcpustat_cpu(j
).cpustat
[CPUTIME_NICE
];
251 static ssize_t
store_freq_step(struct dbs_data
*dbs_data
, const char *buf
,
254 struct cs_dbs_tuners
*cs_tuners
= dbs_data
->tuners
;
257 ret
= sscanf(buf
, "%u", &input
);
266 * no need to test here if freq_step is zero as the user might actually
267 * want this, they would be crazy though :)
269 cs_tuners
->freq_step
= input
;
273 show_store_one(cs
, sampling_rate
);
274 show_store_one(cs
, sampling_down_factor
);
275 show_store_one(cs
, up_threshold
);
276 show_store_one(cs
, down_threshold
);
277 show_store_one(cs
, ignore_nice_load
);
278 show_store_one(cs
, freq_step
);
279 declare_show_sampling_rate_min(cs
);
281 gov_sys_pol_attr_rw(sampling_rate
);
282 gov_sys_pol_attr_rw(sampling_down_factor
);
283 gov_sys_pol_attr_rw(up_threshold
);
284 gov_sys_pol_attr_rw(down_threshold
);
285 gov_sys_pol_attr_rw(ignore_nice_load
);
286 gov_sys_pol_attr_rw(freq_step
);
287 gov_sys_pol_attr_ro(sampling_rate_min
);
289 static struct attribute
*dbs_attributes_gov_sys
[] = {
290 &sampling_rate_min_gov_sys
.attr
,
291 &sampling_rate_gov_sys
.attr
,
292 &sampling_down_factor_gov_sys
.attr
,
293 &up_threshold_gov_sys
.attr
,
294 &down_threshold_gov_sys
.attr
,
295 &ignore_nice_load_gov_sys
.attr
,
296 &freq_step_gov_sys
.attr
,
300 static struct attribute_group cs_attr_group_gov_sys
= {
301 .attrs
= dbs_attributes_gov_sys
,
302 .name
= "conservative",
305 static struct attribute
*dbs_attributes_gov_pol
[] = {
306 &sampling_rate_min_gov_pol
.attr
,
307 &sampling_rate_gov_pol
.attr
,
308 &sampling_down_factor_gov_pol
.attr
,
309 &up_threshold_gov_pol
.attr
,
310 &down_threshold_gov_pol
.attr
,
311 &ignore_nice_load_gov_pol
.attr
,
312 &freq_step_gov_pol
.attr
,
316 static struct attribute_group cs_attr_group_gov_pol
= {
317 .attrs
= dbs_attributes_gov_pol
,
318 .name
= "conservative",
321 /************************** sysfs end ************************/
323 static int cs_init(struct dbs_data
*dbs_data
, bool notify
)
325 struct cs_dbs_tuners
*tuners
;
327 tuners
= kzalloc(sizeof(*tuners
), GFP_KERNEL
);
329 pr_err("%s: kzalloc failed\n", __func__
);
333 tuners
->up_threshold
= DEF_FREQUENCY_UP_THRESHOLD
;
334 tuners
->down_threshold
= DEF_FREQUENCY_DOWN_THRESHOLD
;
335 tuners
->sampling_down_factor
= DEF_SAMPLING_DOWN_FACTOR
;
336 tuners
->ignore_nice_load
= 0;
337 tuners
->freq_step
= DEF_FREQUENCY_STEP
;
339 dbs_data
->tuners
= tuners
;
340 dbs_data
->min_sampling_rate
= MIN_SAMPLING_RATE_RATIO
*
341 jiffies_to_usecs(10);
344 cpufreq_register_notifier(&cs_cpufreq_notifier_block
,
345 CPUFREQ_TRANSITION_NOTIFIER
);
350 static void cs_exit(struct dbs_data
*dbs_data
, bool notify
)
353 cpufreq_unregister_notifier(&cs_cpufreq_notifier_block
,
354 CPUFREQ_TRANSITION_NOTIFIER
);
356 kfree(dbs_data
->tuners
);
359 define_get_cpu_dbs_routines(cs_cpu_dbs_info
);
361 static struct common_dbs_data cs_dbs_cdata
= {
362 .governor
= GOV_CONSERVATIVE
,
363 .attr_group_gov_sys
= &cs_attr_group_gov_sys
,
364 .attr_group_gov_pol
= &cs_attr_group_gov_pol
,
365 .get_cpu_cdbs
= get_cpu_cdbs
,
366 .get_cpu_dbs_info_s
= get_cpu_dbs_info_s
,
367 .gov_dbs_timer
= cs_dbs_timer
,
368 .gov_check_cpu
= cs_check_cpu
,
373 static int cs_cpufreq_governor_dbs(struct cpufreq_policy
*policy
,
376 return cpufreq_governor_dbs(policy
, &cs_dbs_cdata
, event
);
379 static int __init
cpufreq_gov_dbs_init(void)
381 return cpufreq_register_governor(&cpufreq_gov_conservative
);
384 static void __exit
cpufreq_gov_dbs_exit(void)
386 cpufreq_unregister_governor(&cpufreq_gov_conservative
);
389 MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
390 MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
391 "Low Latency Frequency Transition capable processors "
392 "optimised for use in a battery environment");
393 MODULE_LICENSE("GPL");
395 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
396 struct cpufreq_governor
*cpufreq_default_governor(void)
398 return &cpufreq_gov_conservative
;
401 fs_initcall(cpufreq_gov_dbs_init
);
403 module_init(cpufreq_gov_dbs_init
);
405 module_exit(cpufreq_gov_dbs_exit
);