Commit 8e677ce8 authored by Alexander Clouter's avatar Alexander Clouter Committed by Dave Jones
Browse files

[CPUFREQ] conservative: fixup governor to function more like ondemand logic 



As conservative is based off ondemand the codebases occasionally need to be
resync'd.  This patch, although ugly, does this.

Signed-off-by: default avatarAlexander Clouter <alex@digriz.org.uk>
Signed-off-by: default avatarDave Jones <davej@redhat.com>
parent f407a08b

drivers/cpufreq/cpufreq_conservative.c

+188 −140
Original line number Diff line number Diff line
@@ -13,22 +13,17 @@ 


#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/smp.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/ctype.h>

#include <linux/cpufreq.h>

#include <linux/sysctl.h>

#include <linux/types.h>

#include <linux/fs.h>

#include <linux/sysfs.h>

#include <linux/cpu.h>

#include <linux/kmod.h>

#include <linux/workqueue.h>

#include <linux/jiffies.h>

#include <linux/kernel_stat.h>

#include <linux/percpu.h>

#include <linux/mutex.h>

#include <linux/hrtimer.h>

#include <linux/tick.h>

#include <linux/ktime.h>

#include <linux/sched.h>



/*

 * dbs is used in this file as a shortform for demandbased switching

 * It helps to keep variable names smaller, simpler
@@ -43,8 +38,8 @@ 
 * latency of the processor. The governor will work on any processor with

 * transition latency <= 10mS, using appropriate sampling

 * rate.

 * For CPUs with transition latency > 10mS (mostly drivers

 * with CPUFREQ_ETERNAL), this governor will not work.

 * For CPUs with transition latency > 10mS (mostly drivers with CPUFREQ_ETERNAL)

 * this governor will not work.

 * All times here are in uS.

 */

static unsigned int def_sampling_rate;
@@ -75,12 +70,15 @@ static unsigned int minimum_sampling_rate(void) 
static void do_dbs_timer(struct work_struct *work);



struct cpu_dbs_info_s {

	cputime64_t prev_cpu_idle;

	cputime64_t prev_cpu_wall;

	cputime64_t prev_cpu_nice;

	struct cpufreq_policy *cur_policy;

	unsigned int prev_cpu_idle_up;

	unsigned int prev_cpu_idle_down;

	unsigned int enable;

	struct delayed_work work;

	unsigned int down_skip;

	unsigned int requested_freq;

	int cpu;

	unsigned int enable:1;

};

static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
@@ -95,18 +93,17 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */ 
 * is recursive for the same process. -Venki

 */

static DEFINE_MUTEX(dbs_mutex);

static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);



struct dbs_tuners {

static struct workqueue_struct	*kconservative_wq;



static struct dbs_tuners {

	unsigned int sampling_rate;

	unsigned int sampling_down_factor;

	unsigned int up_threshold;

	unsigned int down_threshold;

	unsigned int ignore_nice;

	unsigned int freq_step;

};



static struct dbs_tuners dbs_tuners_ins = {

} dbs_tuners_ins = {

	.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,

	.down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,

	.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
@@ -114,18 +111,37 @@ static struct dbs_tuners dbs_tuners_ins = { 
	.freq_step = 5,

};



static inline unsigned int get_cpu_idle_time(unsigned int cpu)

static inline cputime64_t get_cpu_idle_time_jiffy(unsigned int cpu,

							cputime64_t *wall)

{

	unsigned int add_nice = 0, ret;

	cputime64_t idle_time;

	cputime64_t cur_wall_time;

	cputime64_t busy_time;



	if (dbs_tuners_ins.ignore_nice)

		add_nice = kstat_cpu(cpu).cpustat.nice;

	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());

	busy_time = cputime64_add(kstat_cpu(cpu).cpustat.user,

			kstat_cpu(cpu).cpustat.system);



	busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.irq);

	busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.softirq);

	busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.steal);

	busy_time = cputime64_add(busy_time, kstat_cpu(cpu).cpustat.nice);



	idle_time = cputime64_sub(cur_wall_time, busy_time);

	if (wall)

		*wall = cur_wall_time;



	return idle_time;

}



static inline cputime64_t get_cpu_idle_time(unsigned int cpu, cputime64_t *wall)

{

	u64 idle_time = get_cpu_idle_time_us(cpu, wall);



	ret = kstat_cpu(cpu).cpustat.idle +

		kstat_cpu(cpu).cpustat.iowait +

		add_nice;

	if (idle_time == -1ULL)

		return get_cpu_idle_time_jiffy(cpu, wall);



	return ret;

	return idle_time;

}



/* keep track of frequency transitions */
@@ -213,6 +229,7 @@ static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused, 
	unsigned int input;

	int ret;

	ret = sscanf(buf, "%u", &input);



	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)

		return -EINVAL;
@@ -230,11 +247,10 @@ static ssize_t store_sampling_rate(struct cpufreq_policy *unused, 
	int ret;

	ret = sscanf(buf, "%u", &input);



	mutex_lock(&dbs_mutex);

	if (ret != 1) {

		mutex_unlock(&dbs_mutex);

	if (ret != 1)

		return -EINVAL;

	}



	mutex_lock(&dbs_mutex);

	dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate());

	mutex_unlock(&dbs_mutex);
@@ -269,7 +285,9 @@ static ssize_t store_down_threshold(struct cpufreq_policy *unused, 
	ret = sscanf(buf, "%u", &input);



	mutex_lock(&dbs_mutex);

	if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) {

	/* cannot be lower than 11 otherwise freq will not fall */

	if (ret != 1 || input < 11 || input > 100 ||

			input >= dbs_tuners_ins.up_threshold) {

		mutex_unlock(&dbs_mutex);

		return -EINVAL;

	}
@@ -302,12 +320,14 @@ static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy, 
	}

	dbs_tuners_ins.ignore_nice = input;



	/* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */

	/* we need to re-evaluate prev_cpu_idle */

	for_each_online_cpu(j) {

		struct cpu_dbs_info_s *j_dbs_info;

		j_dbs_info = &per_cpu(cpu_dbs_info, j);

		j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(j);

		j_dbs_info->prev_cpu_idle_down = j_dbs_info->prev_cpu_idle_up;

		struct cpu_dbs_info_s *dbs_info;

		dbs_info = &per_cpu(cpu_dbs_info, j);

		dbs_info->prev_cpu_idle = get_cpu_idle_time(j,

						&dbs_info->prev_cpu_wall);

		if (dbs_tuners_ins.ignore_nice)

			dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;

	}

	mutex_unlock(&dbs_mutex);
@@ -319,7 +339,6 @@ static ssize_t store_freq_step(struct cpufreq_policy *policy, 
{

	unsigned int input;

	int ret;



	ret = sscanf(buf, "%u", &input);



	if (ret != 1)
@@ -367,55 +386,78 @@ static struct attribute_group dbs_attr_group = { 


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



static void dbs_check_cpu(int cpu)

static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)

{

	unsigned int idle_ticks, up_idle_ticks, down_idle_ticks;

	unsigned int tmp_idle_ticks, total_idle_ticks;

	unsigned int load = 0;

	unsigned int freq_target;

	unsigned int freq_down_sampling_rate;

	struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu);

	struct cpufreq_policy *policy;



	if (!this_dbs_info->enable)

		return;

	struct cpufreq_policy *policy;

	unsigned int j;



	policy = this_dbs_info->cur_policy;



	/*

	 * The default safe range is 20% to 80%

	 * Every sampling_rate, we check

	 *	- If current idle time is less than 20%, then we try to

	 *	  increase frequency

	 * Every sampling_rate*sampling_down_factor, we check

	 *	- If current idle time is more than 80%, then we try to

	 *	  decrease frequency

	 * 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%, 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 max_frequency

	 * 5% (default) of maximum frequency

	 */



	/* Check for frequency increase */

	idle_ticks = UINT_MAX;

	/* Get Absolute Load */

	for_each_cpu(j, policy->cpus) {

		struct cpu_dbs_info_s *j_dbs_info;

		cputime64_t cur_wall_time, cur_idle_time;

		unsigned int idle_time, wall_time;



	/* Check for frequency increase */

	total_idle_ticks = get_cpu_idle_time(cpu);

	tmp_idle_ticks = total_idle_ticks -

		this_dbs_info->prev_cpu_idle_up;

	this_dbs_info->prev_cpu_idle_up = total_idle_ticks;

		j_dbs_info = &per_cpu(cpu_dbs_info, j);



		cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);



	if (tmp_idle_ticks < idle_ticks)

		idle_ticks = tmp_idle_ticks;

		wall_time = (unsigned int) cputime64_sub(cur_wall_time,

				j_dbs_info->prev_cpu_wall);

		j_dbs_info->prev_cpu_wall = cur_wall_time;



	/* Scale idle ticks by 100 and compare with up and down ticks */

	idle_ticks *= 100;

	up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *

			usecs_to_jiffies(dbs_tuners_ins.sampling_rate);

		idle_time = (unsigned int) cputime64_sub(cur_idle_time,

				j_dbs_info->prev_cpu_idle);

		j_dbs_info->prev_cpu_idle = cur_idle_time;



		if (dbs_tuners_ins.ignore_nice) {

			cputime64_t cur_nice;

			unsigned long cur_nice_jiffies;



			cur_nice = cputime64_sub(kstat_cpu(j).cpustat.nice,

					 j_dbs_info->prev_cpu_nice);

			/*

			 * Assumption: nice time between sampling periods will

			 * be less than 2^32 jiffies for 32 bit sys

			 */

			cur_nice_jiffies = (unsigned long)

					cputime64_to_jiffies64(cur_nice);



			j_dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;

			idle_time += jiffies_to_usecs(cur_nice_jiffies);

		}



		if (unlikely(!wall_time || wall_time < idle_time))

			continue;



		load = 100 * (wall_time - idle_time) / wall_time;

	}



	/*

	 * break out if we 'cannot' reduce the speed as the user might

	 * want freq_step to be zero

	 */

	if (dbs_tuners_ins.freq_step == 0)

		return;



	if (idle_ticks < up_idle_ticks) {

	/* Check for frequency increase */

	if (load > dbs_tuners_ins.up_threshold) {

		this_dbs_info->down_skip = 0;

		this_dbs_info->prev_cpu_idle_down =

			this_dbs_info->prev_cpu_idle_up;



		/* if we are already at full speed then break out early */

		if (this_dbs_info->requested_freq == policy->max)
@@ -436,49 +478,24 @@ static void dbs_check_cpu(int cpu) 
		return;

	}



	/* Check for frequency decrease */

	this_dbs_info->down_skip++;

	if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor)

		return;



	/* Check for frequency decrease */

	total_idle_ticks = this_dbs_info->prev_cpu_idle_up;

	tmp_idle_ticks = total_idle_ticks -

		this_dbs_info->prev_cpu_idle_down;

	this_dbs_info->prev_cpu_idle_down = total_idle_ticks;



	if (tmp_idle_ticks < idle_ticks)

		idle_ticks = tmp_idle_ticks;



	/* Scale idle ticks by 100 and compare with up and down ticks */

	idle_ticks *= 100;

	this_dbs_info->down_skip = 0;



	freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *

		dbs_tuners_ins.sampling_down_factor;

	down_idle_ticks = (100 - dbs_tuners_ins.down_threshold) *

		usecs_to_jiffies(freq_down_sampling_rate);



	if (idle_ticks > down_idle_ticks) {

	/*

		 * if we are already at the lowest speed then break out early

		 * or if we 'cannot' reduce the speed as the user might want

		 * freq_target to be zero

	 * The optimal frequency is the frequency that is the lowest that

	 * can support the current CPU usage without triggering the up

	 * policy. To be safe, we focus 10 points under the threshold.

	 */

		if (this_dbs_info->requested_freq == policy->min

				|| dbs_tuners_ins.freq_step == 0)

			return;



	if (load < (dbs_tuners_ins.down_threshold - 10)) {

		freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;



		/* max freq cannot be less than 100. But who knows.... */

		if (unlikely(freq_target == 0))

			freq_target = 5;



		this_dbs_info->requested_freq -= freq_target;

		if (this_dbs_info->requested_freq < policy->min)

			this_dbs_info->requested_freq = policy->min;



		/*

		 * if we cannot reduce the frequency anymore, break out early

		 */

		if (policy->cur == policy->min)

			return;



		__cpufreq_driver_target(policy, this_dbs_info->requested_freq,

				CPUFREQ_RELATION_H);

		return;
@@ -487,27 +504,45 @@ static void dbs_check_cpu(int cpu) 


static void do_dbs_timer(struct work_struct *work)

{

	int i;

	mutex_lock(&dbs_mutex);

	for_each_online_cpu(i)

		dbs_check_cpu(i);

	schedule_delayed_work(&dbs_work,

			usecs_to_jiffies(dbs_tuners_ins.sampling_rate));

	mutex_unlock(&dbs_mutex);

	struct cpu_dbs_info_s *dbs_info =

		container_of(work, struct cpu_dbs_info_s, work.work);

	unsigned int cpu = dbs_info->cpu;



	/* We want all CPUs to do sampling nearly on same jiffy */

	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);



	delay -= jiffies % delay;



	if (lock_policy_rwsem_write(cpu) < 0)

		return;



	if (!dbs_info->enable) {

		unlock_policy_rwsem_write(cpu);

		return;

	}



static inline void dbs_timer_init(void)

	dbs_check_cpu(dbs_info);



	queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);

	unlock_policy_rwsem_write(cpu);

}



static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)

{

	init_timer_deferrable(&dbs_work.timer);

	schedule_delayed_work(&dbs_work,

			usecs_to_jiffies(dbs_tuners_ins.sampling_rate));

	return;

	/* We want all CPUs to do sampling nearly on same jiffy */

	int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);

	delay -= jiffies % delay;



	dbs_info->enable = 1;

	INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);

	queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work,

				delay);

}



static inline void dbs_timer_exit(void)

static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)

{

	cancel_delayed_work(&dbs_work);

	return;

	dbs_info->enable = 0;

	cancel_delayed_work(&dbs_info->work);

}



static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@@ -541,11 +576,13 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 
			j_dbs_info = &per_cpu(cpu_dbs_info, j);

			j_dbs_info->cur_policy = policy;



			j_dbs_info->prev_cpu_idle_up = get_cpu_idle_time(cpu);

			j_dbs_info->prev_cpu_idle_down

				= j_dbs_info->prev_cpu_idle_up;

			j_dbs_info->prev_cpu_idle = get_cpu_idle_time(j,

						&j_dbs_info->prev_cpu_wall);

			if (dbs_tuners_ins.ignore_nice) {

				j_dbs_info->prev_cpu_nice =

						kstat_cpu(j).cpustat.nice;

			}

		}

		this_dbs_info->enable = 1;

		this_dbs_info->down_skip = 0;

		this_dbs_info->requested_freq = policy->cur;
@@ -567,30 +604,30 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 


			dbs_tuners_ins.sampling_rate = def_sampling_rate;



			dbs_timer_init();

			cpufreq_register_notifier(

					&dbs_cpufreq_notifier_block,

					CPUFREQ_TRANSITION_NOTIFIER);

		}

		dbs_timer_init(this_dbs_info);



		mutex_unlock(&dbs_mutex);



		break;



	case CPUFREQ_GOV_STOP:

		mutex_lock(&dbs_mutex);

		this_dbs_info->enable = 0;

		dbs_timer_exit(this_dbs_info);

		sysfs_remove_group(&policy->kobj, &dbs_attr_group);

		dbs_enable--;



		/*

		 * Stop the timerschedule work, when this governor

		 * is used for first time

		 */

		if (dbs_enable == 0) {

			dbs_timer_exit();

		if (dbs_enable == 0)

			cpufreq_unregister_notifier(

					&dbs_cpufreq_notifier_block,

					CPUFREQ_TRANSITION_NOTIFIER);

		}



		mutex_unlock(&dbs_mutex);
@@ -607,6 +644,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, 
					this_dbs_info->cur_policy,

					policy->min, CPUFREQ_RELATION_L);

		mutex_unlock(&dbs_mutex);



		break;

	}

	return 0;
@@ -624,15 +662,25 @@ struct cpufreq_governor cpufreq_gov_conservative = { 


static int __init cpufreq_gov_dbs_init(void)

{

	return cpufreq_register_governor(&cpufreq_gov_conservative);

	int err;



	kconservative_wq = create_workqueue("kconservative");

	if (!kconservative_wq) {

		printk(KERN_ERR "Creation of kconservative failed\n");

		return -EFAULT;

	}



	err = cpufreq_register_governor(&cpufreq_gov_conservative);

	if (err)

		destroy_workqueue(kconservative_wq);



	return err;

}



static void __exit cpufreq_gov_dbs_exit(void)

{

	/* Make sure that the scheduled work is indeed not running */

	flush_scheduled_work();



	cpufreq_unregister_governor(&cpufreq_gov_conservative);

	destroy_workqueue(kconservative_wq);

}