Release 4.9 drivers/cpufreq/cpufreq_conservative.c

Directory: drivers/cpufreq
/*
 *  drivers/cpufreq/cpufreq_conservative.c
 *
 *  Copyright (C)  2001 Russell King
 *            (C)  2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *                      Jun Nakajima <jun.nakajima@intel.com>
 *            (C)  2009 Alexander Clouter <alex@digriz.org.uk>
 *
 * 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.
 */

#include <linux/slab.h>
#include "cpufreq_governor.h"


struct cs_policy_dbs_info {
	
struct policy_dbs_info policy_dbs;
	
unsigned int down_skip;
	
unsigned int requested_freq;
};



static inline struct cs_policy_dbs_info *to_dbs_info(struct policy_dbs_info *policy_dbs)
{
	return container_of(policy_dbs, struct cs_policy_dbs_info, policy_dbs);
}

Contributors
Person Tokens Prop Commits CommitProp
rafael j. wysocki rafael j. wysocki 25 100.00% 1 100.00%
Total 25 100.00% 1 100.00%


struct cs_dbs_tuners {
	
unsigned int down_threshold;
	
unsigned int freq_step;
};

/* Conservative governor macros */

#define DEF_FREQUENCY_UP_THRESHOLD		(80)

#define DEF_FREQUENCY_DOWN_THRESHOLD		(20)

#define DEF_FREQUENCY_STEP			(5)

#define DEF_SAMPLING_DOWN_FACTOR		(1)

#define MAX_SAMPLING_DOWN_FACTOR		(10)



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;
}

Contributors
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stratos karafotis stratos karafotis 51 100.00% 1 100.00%
Total 51 100.00% 1 100.00%

/*
 * Every sampling_rate, we check, if current idle time is less than 20%
 * (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
 *
 * Any frequency increase takes it to the maximum frequency. Frequency reduction
 * happens at minimum steps of 5% (default) of maximum frequency
 */


static unsigned int cs_dbs_timer(struct cpufreq_policy *policy)
{
	struct policy_dbs_info *policy_dbs = policy->governor_data;
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy_dbs);
	unsigned int requested_freq = dbs_info->requested_freq;
	struct dbs_data *dbs_data = policy_dbs->dbs_data;
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int load = dbs_update(policy);

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

	/*
         * If requested_freq is out of range, it is likely that the limits
         * changed in the meantime, so fall back to current frequency in that
         * case.
         */
	if (requested_freq > policy->max || requested_freq < policy->min)
		requested_freq = policy->cur;

	/* Check for frequency increase */
	if (load > dbs_data->up_threshold) {
		dbs_info->down_skip = 0;

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

		requested_freq += get_freq_target(cs_tuners, policy);
		if (requested_freq > policy->max)
			requested_freq = policy->max;

		__cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_H);
		dbs_info->requested_freq = requested_freq;
		goto out;
	}

	/* if sampling_down_factor is active break out early */
	if (++dbs_info->down_skip < dbs_data->sampling_down_factor)
		goto out;
	dbs_info->down_skip = 0;

	/* Check for frequency decrease */
	if (load < cs_tuners->down_threshold) {
		unsigned int freq_target;
		/*
                 * if we cannot reduce the frequency anymore, break out early
                 */
		if (requested_freq == policy->min)
			goto out;

		freq_target = get_freq_target(cs_tuners, policy);
		if (requested_freq > freq_target)
			requested_freq -= freq_target;
		else
			requested_freq = policy->min;

		__cpufreq_driver_target(policy, requested_freq, CPUFREQ_RELATION_L);
		dbs_info->requested_freq = requested_freq;
	}

 out:
	return dbs_data->sampling_rate;
}

Contributors
Person Tokens Prop Commits CommitProp
rafael j. wysocki rafael j. wysocki 106 40.00% 5 27.78%
viresh kumar viresh kumar 78 29.43% 5 27.78%
stratos karafotis stratos karafotis 30 11.32% 3 16.67%
xiaoguang chen xiaoguang chen 23 8.68% 1 5.56%
elias oltmanns elias oltmanns 16 6.04% 1 5.56%
namhyung kim namhyung kim 9 3.40% 2 11.11%
alexander clouter alexander clouter 3 1.13% 1 5.56%
Total 265 100.00% 18 100.00%

/************************** sysfs interface ************************/



static ssize_t store_sampling_down_factor(struct gov_attr_set *attr_set,
					  const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

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

	dbs_data->sampling_down_factor = input;
	return count;
}

Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 53 70.67% 3 42.86%
rafael j. wysocki rafael j. wysocki 12 16.00% 1 14.29%
alexander clouter alexander clouter 5 6.67% 1 14.29%
dave jones dave jones 4 5.33% 1 14.29%
venkatesh pallipadi venkatesh pallipadi 1 1.33% 1 14.29%
Total 75 100.00% 7 100.00%



static ssize_t store_up_threshold(struct gov_attr_set *attr_set,
				  const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

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

	dbs_data->up_threshold = input;
	return count;
}

Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 59 68.60% 3 50.00%
rafael j. wysocki rafael j. wysocki 12 13.95% 1 16.67%
dave jones dave jones 9 10.47% 1 16.67%
alexander clouter alexander clouter 6 6.98% 1 16.67%
Total 86 100.00% 6 100.00%



static ssize_t store_down_threshold(struct gov_attr_set *attr_set,
				    const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

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

	cs_tuners->down_threshold = input;
	return count;
}

Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 68 74.73% 3 50.00%
rafael j. wysocki rafael j. wysocki 12 13.19% 1 16.67%
dave jones dave jones 9 9.89% 1 16.67%
alexander clouter alexander clouter 2 2.20% 1 16.67%
Total 91 100.00% 6 100.00%



static ssize_t store_ignore_nice_load(struct gov_attr_set *attr_set,
				      const char *buf, size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	unsigned int input;
	int ret;

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

	if (input > 1)
		input = 1;

	if (input == dbs_data->ignore_nice_load) /* nothing to do */
		return count;

	dbs_data->ignore_nice_load = input;

	/* we need to re-evaluate prev_cpu_idle */
	gov_update_cpu_data(dbs_data);

	return count;
}

Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 57 60.00% 4 44.44%
dave jones dave jones 22 23.16% 1 11.11%
rafael j. wysocki rafael j. wysocki 13 13.68% 2 22.22%
jeff garzik jeff garzik 2 2.11% 1 11.11%
alexander clouter alexander clouter 1 1.05% 1 11.11%
Total 95 100.00% 9 100.00%



static ssize_t store_freq_step(struct gov_attr_set *attr_set, const char *buf,
			       size_t count)
{
	struct dbs_data *dbs_data = to_dbs_data(attr_set);
	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
	unsigned int input;
	int ret;
	ret = sscanf(buf, "%u", &input);

	if (ret != 1)
		return -EINVAL;

	if (input > 100)
		input = 100;

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

Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 60 68.97% 2 28.57%
rafael j. wysocki rafael j. wysocki 12 13.79% 1 14.29%
dave jones dave jones 9 10.34% 1 14.29%
venkatesh pallipadi venkatesh pallipadi 4 4.60% 1 14.29%
alexander clouter alexander clouter 1 1.15% 1 14.29%
thomas renninger thomas renninger 1 1.15% 1 14.29%
Total 87 100.00% 7 100.00%


gov_show_one_common(sampling_rate);

gov_show_one_common(sampling_down_factor);

gov_show_one_common(up_threshold);

gov_show_one_common(ignore_nice_load);

gov_show_one_common(min_sampling_rate);
gov_show_one(cs, down_threshold);
gov_show_one(cs, freq_step);


gov_attr_rw(sampling_rate);

gov_attr_rw(sampling_down_factor);

gov_attr_rw(up_threshold);

gov_attr_rw(ignore_nice_load);

gov_attr_ro(min_sampling_rate);

gov_attr_rw(down_threshold);

gov_attr_rw(freq_step);


static struct attribute *cs_attributes[] = {
	&min_sampling_rate.attr,
	&sampling_rate.attr,
	&sampling_down_factor.attr,
	&up_threshold.attr,
	&down_threshold.attr,
	&ignore_nice_load.attr,
	&freq_step.attr,
	NULL
};

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



static struct policy_dbs_info *cs_alloc(void)
{
	struct cs_policy_dbs_info *dbs_info;

	dbs_info = kzalloc(sizeof(*dbs_info), GFP_KERNEL);
	return dbs_info ? &dbs_info->policy_dbs : NULL;
}

Contributors
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rafael j. wysocki rafael j. wysocki 38 100.00% 1 100.00%
Total 38 100.00% 1 100.00%



static void cs_free(struct policy_dbs_info *policy_dbs)
{
	kfree(to_dbs_info(policy_dbs));
}

Contributors
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rafael j. wysocki rafael j. wysocki 19 100.00% 1 100.00%
Total 19 100.00% 1 100.00%



static int cs_init(struct dbs_data *dbs_data)
{
	struct cs_dbs_tuners *tuners;

	tuners = kzalloc(sizeof(*tuners), GFP_KERNEL);
	if (!tuners)
		return -ENOMEM;

	tuners->down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD;
	tuners->freq_step = DEF_FREQUENCY_STEP;
	dbs_data->up_threshold = DEF_FREQUENCY_UP_THRESHOLD;
	dbs_data->sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR;
	dbs_data->ignore_nice_load = 0;

	dbs_data->tuners = tuners;
	dbs_data->min_sampling_rate = MIN_SAMPLING_RATE_RATIO *
		jiffies_to_usecs(10);

	return 0;
}

Contributors
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viresh kumar viresh kumar 88 100.00% 4 100.00%
Total 88 100.00% 4 100.00%



static void cs_exit(struct dbs_data *dbs_data)
{
	kfree(dbs_data->tuners);
}

Contributors
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viresh kumar viresh kumar 18 100.00% 1 100.00%
Total 18 100.00% 1 100.00%



static void cs_start(struct cpufreq_policy *policy)
{
	struct cs_policy_dbs_info *dbs_info = to_dbs_info(policy->governor_data);

	dbs_info->down_skip = 0;
	dbs_info->requested_freq = policy->cur;
}

Contributors
Person Tokens Prop Commits CommitProp
rafael j. wysocki rafael j. wysocki 37 100.00% 3 100.00%
Total 37 100.00% 3 100.00%


static struct dbs_governor cs_governor = {
	.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
	.kobj_type = { .default_attrs = cs_attributes },
	.gov_dbs_timer = cs_dbs_timer,
	.alloc = cs_alloc,
	.free = cs_free,
	.init = cs_init,
	.exit = cs_exit,
	.start = cs_start,
};


#define CPU_FREQ_GOV_CONSERVATIVE	(&cs_governor.gov)



static int __init cpufreq_gov_dbs_init(void)
{
	return cpufreq_register_governor(CPU_FREQ_GOV_CONSERVATIVE);
}

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dave jones dave jones 14 93.33% 1 50.00%
rafael j. wysocki rafael j. wysocki 1 6.67% 1 50.00%
Total 15 100.00% 2 100.00%



static void __exit cpufreq_gov_dbs_exit(void)
{
	cpufreq_unregister_governor(CPU_FREQ_GOV_CONSERVATIVE);
}

Contributors
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dave jones dave jones 13 92.86% 1 50.00%
rafael j. wysocki rafael j. wysocki 1 7.14% 1 50.00%
Total 14 100.00% 2 100.00%

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

#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE


struct cpufreq_governor *cpufreq_default_governor(void)
{
	return CPU_FREQ_GOV_CONSERVATIVE;
}

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rafael j. wysocki rafael j. wysocki 12 100.00% 2 100.00%
Total 12 100.00% 2 100.00%


fs_initcall(cpufreq_gov_dbs_init);
#else

module_init(cpufreq_gov_dbs_init);
#endif

module_exit(cpufreq_gov_dbs_exit);
Overall Contributors
Person Tokens Prop Commits CommitProp
viresh kumar viresh kumar 606 46.80% 9 20.93%
rafael j. wysocki rafael j. wysocki 359 27.72% 13 30.23%
dave jones dave jones 127 9.81% 1 2.33%
stratos karafotis stratos karafotis 87 6.72% 4 9.30%
alexander clouter alexander clouter 28 2.16% 5 11.63%
xiaoguang chen xiaoguang chen 23 1.78% 1 2.33%
elias oltmanns elias oltmanns 19 1.47% 1 2.33%
thomas renninger thomas renninger 14 1.08% 3 6.98%
johannes weiner johannes weiner 12 0.93% 1 2.33%
namhyung kim namhyung kim 9 0.69% 2 4.65%
venkatesh pallipadi venkatesh pallipadi 9 0.69% 2 4.65%
jeff garzik jeff garzik 2 0.15% 1 2.33%
Total 1295 100.00% 43 100.00%
  Directory: drivers/cpufreq
	Person	Tokens	Prop	Commits	CommitProp
rafael j. wysocki	rafael j. wysocki	25	100.00%	1	100.00%
	Total	25	100.00%	1	100.00%
cregit-Linux how code gets into the kernel

Release 4.9 drivers/cpufreq/cpufreq_conservative.c

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