cpufreq_conservative.c 11.1 KB
Newer Older
1 2 3 4 5 6
/*
 *  drivers/cpufreq/cpufreq_conservative.c
 *
 *  Copyright (C)  2001 Russell King
 *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *                      Jun Nakajima <jun.nakajima@intel.com>
7
 *            (C)  2009 Alexander Clouter <alex@digriz.org.uk>
8 9 10 11 12 13
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

14
#include <linux/slab.h>
15
#include "cpufreq_governor.h"
16

17
/* Conservative governor macros */
18 19
#define DEF_FREQUENCY_UP_THRESHOLD		(80)
#define DEF_FREQUENCY_DOWN_THRESHOLD		(20)
20
#define DEF_FREQUENCY_STEP			(5)
21 22
#define DEF_SAMPLING_DOWN_FACTOR		(1)
#define MAX_SAMPLING_DOWN_FACTOR		(10)
23

24
static DEFINE_PER_CPU(struct cs_cpu_dbs_info_s, cs_cpu_dbs_info);
25

26 27 28 29 30 31 32 33 34 35 36 37
static inline unsigned int get_freq_target(struct cs_dbs_tuners *cs_tuners,
					   struct cpufreq_policy *policy)
{
	unsigned int freq_target = (cs_tuners->freq_step * policy->max) / 100;

	/* max freq cannot be less than 100. But who knows... */
	if (unlikely(freq_target == 0))
		freq_target = DEF_FREQUENCY_STEP;

	return freq_target;
}

38 39
/*
 * Every sampling_rate, we check, if current idle time is less than 20%
40 41 42
 * (default), then we try to increase frequency. Every sampling_rate *
 * sampling_down_factor, we check, if current idle time is more than 80%
 * (default), then we try to decrease frequency
43 44 45 46 47
 *
 * Any frequency increase takes it to the maximum frequency. Frequency reduction
 * happens at minimum steps of 5% (default) of maximum frequency
 */
static void cs_check_cpu(int cpu, unsigned int load)
48
{
49
	struct cs_cpu_dbs_info_s *dbs_info = &per_cpu(cs_cpu_dbs_info, cpu);
50
	struct cpufreq_policy *policy = dbs_info->cdbs.policy;
51 52
	struct dbs_data *dbs_data = policy->governor_data;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
53 54 55 56 57

	/*
	 * break out if we 'cannot' reduce the speed as the user might
	 * want freq_step to be zero
	 */
58
	if (cs_tuners->freq_step == 0)
59 60 61
		return;

	/* Check for frequency increase */
62
	if (load > cs_tuners->up_threshold) {
63 64 65 66 67 68
		dbs_info->down_skip = 0;

		/* if we are already at full speed then break out early */
		if (dbs_info->requested_freq == policy->max)
			return;

69
		dbs_info->requested_freq += get_freq_target(cs_tuners, policy);
70

71 72 73
		if (dbs_info->requested_freq > policy->max)
			dbs_info->requested_freq = policy->max;

74 75 76 77 78
		__cpufreq_driver_target(policy, dbs_info->requested_freq,
			CPUFREQ_RELATION_H);
		return;
	}

79 80 81 82 83
	/* if sampling_down_factor is active break out early */
	if (++dbs_info->down_skip < cs_tuners->sampling_down_factor)
		return;
	dbs_info->down_skip = 0;

84 85
	/* Check for frequency decrease */
	if (load < cs_tuners->down_threshold) {
86
		unsigned int freq_target;
87 88 89 90 91 92
		/*
		 * if we cannot reduce the frequency anymore, break out early
		 */
		if (policy->cur == policy->min)
			return;

93 94 95 96 97
		freq_target = get_freq_target(cs_tuners, policy);
		if (dbs_info->requested_freq > freq_target)
			dbs_info->requested_freq -= freq_target;
		else
			dbs_info->requested_freq = policy->min;
98

99
		__cpufreq_driver_target(policy, dbs_info->requested_freq,
100
				CPUFREQ_RELATION_L);
101 102 103 104
		return;
	}
}

105
static void cs_dbs_timer(struct work_struct *work)
106
{
107
	struct cs_cpu_dbs_info_s *dbs_info = container_of(work,
108
			struct cs_cpu_dbs_info_s, cdbs.dwork.work);
109
	unsigned int cpu = dbs_info->cdbs.policy->cpu;
110 111
	struct cs_cpu_dbs_info_s *core_dbs_info = &per_cpu(cs_cpu_dbs_info,
			cpu);
112
	struct dbs_data *dbs_data = dbs_info->cdbs.policy->governor_data;
113 114
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	int delay = delay_for_sampling_rate(cs_tuners->sampling_rate);
115
	bool modify_all = true;
116

117
	mutex_lock(&core_dbs_info->cdbs.timer_mutex);
118 119 120
	if (!need_load_eval(&core_dbs_info->cdbs, cs_tuners->sampling_rate))
		modify_all = false;
	else
121
		dbs_check_cpu(dbs_data, cpu);
122

123
	gov_queue_work(dbs_data, dbs_info->cdbs.policy, delay, modify_all);
124
	mutex_unlock(&core_dbs_info->cdbs.timer_mutex);
125 126
}

127 128 129 130 131 132
static int dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
		void *data)
{
	struct cpufreq_freqs *freq = data;
	struct cs_cpu_dbs_info_s *dbs_info =
					&per_cpu(cs_cpu_dbs_info, freq->cpu);
133 134
	struct cpufreq_policy *policy;

135
	if (!dbs_info->enable)
136 137
		return 0;

138
	policy = dbs_info->cdbs.policy;
139 140

	/*
141
	 * we only care if our internally tracked freq moves outside the 'valid'
142
	 * ranges of frequency available to us otherwise we do not change it
143
	*/
144 145 146
	if (dbs_info->requested_freq > policy->max
			|| dbs_info->requested_freq < policy->min)
		dbs_info->requested_freq = freq->new;
147 148 149 150

	return 0;
}

151 152 153 154
static struct notifier_block cs_cpufreq_notifier_block = {
	.notifier_call = dbs_cpufreq_notifier,
};

155
/************************** sysfs interface ************************/
156
static struct common_dbs_data cs_dbs_cdata;
157

158 159
static ssize_t store_sampling_down_factor(struct dbs_data *dbs_data,
		const char *buf, size_t count)
160
{
161
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
162 163
	unsigned int input;
	int ret;
164
	ret = sscanf(buf, "%u", &input);
165

166
	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
167 168
		return -EINVAL;

169
	cs_tuners->sampling_down_factor = input;
170 171 172
	return count;
}

173 174
static ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
		size_t count)
175
{
176
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
177 178
	unsigned int input;
	int ret;
179
	ret = sscanf(buf, "%u", &input);
180

181
	if (ret != 1)
182
		return -EINVAL;
183

184
	cs_tuners->sampling_rate = max(input, dbs_data->min_sampling_rate);
185 186 187
	return count;
}

188 189
static ssize_t store_up_threshold(struct dbs_data *dbs_data, const char *buf,
		size_t count)
190
{
191
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
192 193
	unsigned int input;
	int ret;
194
	ret = sscanf(buf, "%u", &input);
195

196
	if (ret != 1 || input > 100 || input <= cs_tuners->down_threshold)
197 198
		return -EINVAL;

199
	cs_tuners->up_threshold = input;
200 201 202
	return count;
}

203 204
static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf,
		size_t count)
205
{
206
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
207 208
	unsigned int input;
	int ret;
209
	ret = sscanf(buf, "%u", &input);
210

211 212
	/* cannot be lower than 11 otherwise freq will not fall */
	if (ret != 1 || input < 11 || input > 100 ||
213
			input >= cs_tuners->up_threshold)
214 215
		return -EINVAL;

216
	cs_tuners->down_threshold = input;
217 218 219
	return count;
}

220 221
static ssize_t store_ignore_nice_load(struct dbs_data *dbs_data,
		const char *buf, size_t count)
222
{
223
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
224
	unsigned int input, j;
225 226
	int ret;

227 228
	ret = sscanf(buf, "%u", &input);
	if (ret != 1)
229 230
		return -EINVAL;

231
	if (input > 1)
232
		input = 1;
233

234
	if (input == cs_tuners->ignore_nice_load) /* nothing to do */
235
		return count;
236

237
	cs_tuners->ignore_nice_load = input;
238

239
	/* we need to re-evaluate prev_cpu_idle */
240
	for_each_online_cpu(j) {
241
		struct cs_cpu_dbs_info_s *dbs_info;
242
		dbs_info = &per_cpu(cs_cpu_dbs_info, j);
243
		dbs_info->cdbs.prev_cpu_idle = get_cpu_idle_time(j,
244
					&dbs_info->cdbs.prev_cpu_wall, 0);
245
		if (cs_tuners->ignore_nice_load)
246 247
			dbs_info->cdbs.prev_cpu_nice =
				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
248 249 250 251
	}
	return count;
}

252 253
static ssize_t store_freq_step(struct dbs_data *dbs_data, const char *buf,
		size_t count)
254
{
255
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
256 257
	unsigned int input;
	int ret;
258
	ret = sscanf(buf, "%u", &input);
259

260
	if (ret != 1)
261 262
		return -EINVAL;

263
	if (input > 100)
264
		input = 100;
265

266 267 268 269
	/*
	 * no need to test here if freq_step is zero as the user might actually
	 * want this, they would be crazy though :)
	 */
270
	cs_tuners->freq_step = input;
271 272 273
	return count;
}

274 275 276 277
show_store_one(cs, sampling_rate);
show_store_one(cs, sampling_down_factor);
show_store_one(cs, up_threshold);
show_store_one(cs, down_threshold);
278
show_store_one(cs, ignore_nice_load);
279 280 281 282 283 284 285
show_store_one(cs, freq_step);
declare_show_sampling_rate_min(cs);

gov_sys_pol_attr_rw(sampling_rate);
gov_sys_pol_attr_rw(sampling_down_factor);
gov_sys_pol_attr_rw(up_threshold);
gov_sys_pol_attr_rw(down_threshold);
286
gov_sys_pol_attr_rw(ignore_nice_load);
287 288 289 290 291 292 293 294 295
gov_sys_pol_attr_rw(freq_step);
gov_sys_pol_attr_ro(sampling_rate_min);

static struct attribute *dbs_attributes_gov_sys[] = {
	&sampling_rate_min_gov_sys.attr,
	&sampling_rate_gov_sys.attr,
	&sampling_down_factor_gov_sys.attr,
	&up_threshold_gov_sys.attr,
	&down_threshold_gov_sys.attr,
296
	&ignore_nice_load_gov_sys.attr,
297
	&freq_step_gov_sys.attr,
298 299 300
	NULL
};

301 302 303 304 305 306 307 308 309 310 311
static struct attribute_group cs_attr_group_gov_sys = {
	.attrs = dbs_attributes_gov_sys,
	.name = "conservative",
};

static struct attribute *dbs_attributes_gov_pol[] = {
	&sampling_rate_min_gov_pol.attr,
	&sampling_rate_gov_pol.attr,
	&sampling_down_factor_gov_pol.attr,
	&up_threshold_gov_pol.attr,
	&down_threshold_gov_pol.attr,
312
	&ignore_nice_load_gov_pol.attr,
313 314 315 316 317 318
	&freq_step_gov_pol.attr,
	NULL
};

static struct attribute_group cs_attr_group_gov_pol = {
	.attrs = dbs_attributes_gov_pol,
319 320 321 322 323
	.name = "conservative",
};

/************************** sysfs end ************************/

324
static int cs_init(struct dbs_data *dbs_data, bool notify)
325 326 327
{
	struct cs_dbs_tuners *tuners;

328
	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
329 330 331 332 333 334 335 336
	if (!tuners) {
		pr_err("%s: kzalloc failed\n", __func__);
		return -ENOMEM;
	}

	tuners->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
	tuners->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
337
	tuners->ignore_nice_load = 0;
338
	tuners->freq_step = DEF_FREQUENCY_STEP;
339 340 341 342

	dbs_data->tuners = tuners;
	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
		jiffies_to_usecs(10);
343 344 345 346 347

	if (notify)
		cpufreq_register_notifier(&cs_cpufreq_notifier_block,
					  CPUFREQ_TRANSITION_NOTIFIER);

348 349 350
	return 0;
}

351
static void cs_exit(struct dbs_data *dbs_data, bool notify)
352
{
353 354 355 356
	if (notify)
		cpufreq_unregister_notifier(&cs_cpufreq_notifier_block,
					    CPUFREQ_TRANSITION_NOTIFIER);

357 358 359
	kfree(dbs_data->tuners);
}

360
define_get_cpu_dbs_routines(cs_cpu_dbs_info);
361

362
static struct common_dbs_data cs_dbs_cdata = {
363
	.governor = GOV_CONSERVATIVE,
364 365
	.attr_group_gov_sys = &cs_attr_group_gov_sys,
	.attr_group_gov_pol = &cs_attr_group_gov_pol,
366 367 368 369
	.get_cpu_cdbs = get_cpu_cdbs,
	.get_cpu_dbs_info_s = get_cpu_dbs_info_s,
	.gov_dbs_timer = cs_dbs_timer,
	.gov_check_cpu = cs_check_cpu,
370 371
	.init = cs_init,
	.exit = cs_exit,
372
	.mutex = __MUTEX_INITIALIZER(cs_dbs_cdata.mutex),
373
};
374

375
static int cs_cpufreq_governor_dbs(struct cpufreq_policy *policy,
376 377
				   unsigned int event)
{
378
	return cpufreq_governor_dbs(policy, &cs_dbs_cdata, event);
379 380
}

381 382 383
#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
static
#endif
384 385
struct cpufreq_governor cpufreq_gov_conservative = {
	.name			= "conservative",
386
	.governor		= cs_cpufreq_governor_dbs,
387 388
	.max_transition_latency	= TRANSITION_LATENCY_LIMIT,
	.owner			= THIS_MODULE,
389 390 391 392
};

static int __init cpufreq_gov_dbs_init(void)
{
393
	return cpufreq_register_governor(&cpufreq_gov_conservative);
394 395 396 397
}

static void __exit cpufreq_gov_dbs_exit(void)
{
398
	cpufreq_unregister_governor(&cpufreq_gov_conservative);
399 400
}

401
MODULE_AUTHOR("Alexander Clouter <alex@digriz.org.uk>");
402
MODULE_DESCRIPTION("'cpufreq_conservative' - A dynamic cpufreq governor for "
403 404
		"Low Latency Frequency Transition capable processors "
		"optimised for use in a battery environment");
405
MODULE_LICENSE("GPL");
406

407 408 409
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
fs_initcall(cpufreq_gov_dbs_init);
#else
410
module_init(cpufreq_gov_dbs_init);
411
#endif
412
module_exit(cpufreq_gov_dbs_exit);