* Copyright (C) 2001 Russell King
* (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
* Jun Nakajima <jun.nakajima@intel.com>
- * (C) 2004 Alexander Clouter <alex-kernel@digriz.org.uk>
+ * (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
#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
* 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;
#define MIN_SAMPLING_RATE_RATIO (2)
/* for correct statistics, we need at least 10 ticks between each measure */
-#define MIN_STAT_SAMPLING_RATE \
+#define MIN_STAT_SAMPLING_RATE \
(MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
#define MIN_SAMPLING_RATE \
(def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
+/* Above MIN_SAMPLING_RATE will vanish with its sysfs file soon
+ * Define the minimal settable sampling rate to the greater of:
+ * - "HW transition latency" * 100 (same as default sampling / 10)
+ * - MIN_STAT_SAMPLING_RATE
+ * To avoid that userspace shoots itself.
+*/
+static unsigned int minimum_sampling_rate(void)
+{
+ return max(def_sampling_rate / 10, MIN_STAT_SAMPLING_RATE);
+}
+
+/* This will also vanish soon with removing sampling_rate_max */
#define MAX_SAMPLING_RATE (500 * def_sampling_rate)
-#define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000)
+#define LATENCY_MULTIPLIER (1000)
#define DEF_SAMPLING_DOWN_FACTOR (1)
#define MAX_SAMPLING_DOWN_FACTOR (10)
#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
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);
* cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
* is recursive for the same process. -Venki
*/
-static DEFINE_MUTEX (dbs_mutex);
-static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);
+static DEFINE_MUTEX(dbs_mutex);
-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,
.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 */
struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info,
freq->cpu);
+ struct cpufreq_policy *policy;
+
if (!this_dbs_info->enable)
return 0;
- this_dbs_info->requested_freq = freq->new;
+ policy = this_dbs_info->cur_policy;
+
+ /*
+ * we only care if our internally tracked freq moves outside
+ * the 'valid' ranges of freqency available to us otherwise
+ * we do not change it
+ */
+ if (this_dbs_info->requested_freq > policy->max
+ || this_dbs_info->requested_freq < policy->min)
+ this_dbs_info->requested_freq = freq->new;
return 0;
}
/************************** sysfs interface ************************/
static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
{
- return sprintf (buf, "%u\n", MAX_SAMPLING_RATE);
+ static int print_once;
+
+ if (!print_once) {
+ printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max "
+ "sysfs file is deprecated - used by: %s\n",
+ current->comm);
+ print_once = 1;
+ }
+ return sprintf(buf, "%u\n", MAX_SAMPLING_RATE);
}
static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
{
- return sprintf (buf, "%u\n", MIN_SAMPLING_RATE);
+ static int print_once;
+
+ if (!print_once) {
+ printk(KERN_INFO "CPUFREQ: conservative sampling_rate_max "
+ "sysfs file is deprecated - used by: %s\n", current->comm);
+ print_once = 1;
+ }
+ return sprintf(buf, "%u\n", MIN_SAMPLING_RATE);
}
-#define define_one_ro(_name) \
-static struct freq_attr _name = \
+#define define_one_ro(_name) \
+static struct freq_attr _name = \
__ATTR(_name, 0444, show_##_name, NULL)
define_one_ro(sampling_rate_max);
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
+
if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
return -EINVAL;
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
- mutex_lock(&dbs_mutex);
- if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
- mutex_unlock(&dbs_mutex);
+ if (ret != 1)
return -EINVAL;
- }
- dbs_tuners_ins.sampling_rate = input;
+ mutex_lock(&dbs_mutex);
+ dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate());
mutex_unlock(&dbs_mutex);
return count;
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
mutex_lock(&dbs_mutex);
- if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) {
+ if (ret != 1 || input > 100 ||
+ input <= dbs_tuners_ins.down_threshold) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
}
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ 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;
}
}
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);
{
unsigned int input;
int ret;
-
ret = sscanf(buf, "%u", &input);
if (ret != 1)
define_one_rw(ignore_nice_load);
define_one_rw(freq_step);
-static struct attribute * dbs_attributes[] = {
+static struct attribute *dbs_attributes[] = {
&sampling_rate_max.attr,
&sampling_rate_min.attr,
&sampling_rate.attr,
/************************** 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);
+
+ wall_time = (unsigned int) cputime64_sub(cur_wall_time,
+ j_dbs_info->prev_cpu_wall);
+ j_dbs_info->prev_cpu_wall = cur_wall_time;
+
+ 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);
- if (tmp_idle_ticks < idle_ticks)
- idle_ticks = tmp_idle_ticks;
+ 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;
+ }
- /* 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);
+ /*
+ * 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)
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
- */
- if (this_dbs_info->requested_freq == policy->min
- || dbs_tuners_ins.freq_step == 0)
- return;
-
+ /*
+ * 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 (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;
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;
+ }
+
+ 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(void)
+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,
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;
if (latency == 0)
latency = 1;
- def_sampling_rate = 10 * latency *
- DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
-
- if (def_sampling_rate < MIN_STAT_SAMPLING_RATE)
- def_sampling_rate = MIN_STAT_SAMPLING_RATE;
+ def_sampling_rate =
+ max(latency * LATENCY_MULTIPLIER,
+ MIN_STAT_SAMPLING_RATE);
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);
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
+
break;
}
return 0;
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);
}
-MODULE_AUTHOR ("Alexander Clouter <alex-kernel@digriz.org.uk>");
-MODULE_DESCRIPTION ("'cpufreq_conservative' - A dynamic cpufreq governor for "
+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");
+MODULE_LICENSE("GPL");
#ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
fs_initcall(cpufreq_gov_dbs_init);
git.samba.org / sfrench / cifs-2.6.git / blobdiff