* 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/sched.h>
-#include <linux/kmod.h>
-#include <linux/workqueue.h>
+#include <linux/cpu.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
*/
#define DEF_FREQUENCY_UP_THRESHOLD (80)
-#define MIN_FREQUENCY_UP_THRESHOLD (0)
-#define MAX_FREQUENCY_UP_THRESHOLD (100)
-
#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
-#define MIN_FREQUENCY_DOWN_THRESHOLD (0)
-#define MAX_FREQUENCY_DOWN_THRESHOLD (100)
-/*
- * The polling frequency of this governor depends on the capability of
+/*
+ * The polling frequency of this governor depends on the capability of
* the processor. Default polling frequency is 1000 times the transition
- * latency of the processor. The governor will work on any processor with
- * transition latency <= 10mS, using appropriate sampling
+ * 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.
* All times here are in uS.
*/
-static unsigned int def_sampling_rate;
-#define MIN_SAMPLING_RATE (def_sampling_rate / 2)
+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 \
+ (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 (100000)
-#define DEF_SAMPLING_DOWN_FACTOR (5)
-#define TRANSITION_LATENCY_LIMIT (10 * 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(void *data);
+static void do_dbs_timer(struct work_struct *work);
struct cpu_dbs_info_s {
- struct cpufreq_policy *cur_policy;
- unsigned int prev_cpu_idle_up;
- unsigned int prev_cpu_idle_down;
- unsigned int enable;
+ cputime64_t prev_cpu_idle;
+ cputime64_t prev_cpu_wall;
+ cputime64_t prev_cpu_nice;
+ struct cpufreq_policy *cur_policy;
+ 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);
static unsigned int dbs_enable; /* number of CPUs using this policy */
-static DECLARE_MUTEX (dbs_sem);
-static DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
+/*
+ * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug
+ * lock and dbs_mutex. cpu_hotplug lock should always be held before
+ * dbs_mutex. If any function that can potentially take cpu_hotplug lock
+ * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then
+ * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock
+ * is recursive for the same process. -Venki
+ * DEADLOCK ALERT! (2) : do_dbs_timer() must not take the dbs_mutex, because it
+ * would deadlock with cancel_delayed_work_sync(), which is needed for proper
+ * raceless workqueue teardown.
+ */
+static DEFINE_MUTEX(dbs_mutex);
-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 workqueue_struct *kconservative_wq;
-static struct dbs_tuners dbs_tuners_ins = {
- .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
- .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
- .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
+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;
+} dbs_tuners_ins = {
+ .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
+ .down_threshold = DEF_FREQUENCY_DOWN_THRESHOLD,
+ .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
+ .ignore_nice = 0,
+ .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)
{
- return kstat_cpu(cpu).cpustat.idle +
- kstat_cpu(cpu).cpustat.iowait +
- ( !dbs_tuners_ins.ignore_nice ?
- kstat_cpu(cpu).cpustat.nice :
- 0);
+ cputime64_t idle_time;
+ cputime64_t cur_wall_time;
+ cputime64_t busy_time;
+
+ 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);
+
+ if (idle_time == -1ULL)
+ return get_cpu_idle_time_jiffy(cpu, wall);
+
+ return idle_time;
+}
+
+/* keep track of frequency transitions */
+static int
+dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
+ void *data)
+{
+ struct cpufreq_freqs *freq = data;
+ 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;
+
+ 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;
}
+static struct notifier_block dbs_cpufreq_notifier_block = {
+ .notifier_call = dbs_cpufreq_notifier
+};
+
/************************** 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);
show_one(sampling_down_factor, sampling_down_factor);
show_one(up_threshold, up_threshold);
show_one(down_threshold, down_threshold);
-show_one(ignore_nice, ignore_nice);
+show_one(ignore_nice_load, ignore_nice);
show_one(freq_step, freq_step);
-static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
+static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
const char *buf, size_t count)
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
- if (ret != 1 )
+ ret = sscanf(buf, "%u", &input);
+
+ if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
return -EINVAL;
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
dbs_tuners_ins.sampling_down_factor = input;
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
-static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
+static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
const char *buf, size_t count)
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
- down(&dbs_sem);
- if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
- up(&dbs_sem);
+ if (ret != 1)
return -EINVAL;
- }
- dbs_tuners_ins.sampling_rate = input;
- up(&dbs_sem);
+ mutex_lock(&dbs_mutex);
+ dbs_tuners_ins.sampling_rate = max(input, minimum_sampling_rate());
+ mutex_unlock(&dbs_mutex);
return count;
}
-static ssize_t store_up_threshold(struct cpufreq_policy *unused,
+static ssize_t store_up_threshold(struct cpufreq_policy *unused,
const char *buf, size_t count)
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
- down(&dbs_sem);
- if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
- input < MIN_FREQUENCY_UP_THRESHOLD ||
+ mutex_lock(&dbs_mutex);
+ if (ret != 1 || input > 100 ||
input <= dbs_tuners_ins.down_threshold) {
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return -EINVAL;
}
dbs_tuners_ins.up_threshold = input;
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
-static ssize_t store_down_threshold(struct cpufreq_policy *unused,
+static ssize_t store_down_threshold(struct cpufreq_policy *unused,
const char *buf, size_t count)
{
unsigned int input;
int ret;
- ret = sscanf (buf, "%u", &input);
+ ret = sscanf(buf, "%u", &input);
- down(&dbs_sem);
- if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD ||
- input < MIN_FREQUENCY_DOWN_THRESHOLD ||
+ mutex_lock(&dbs_mutex);
+ /* cannot be lower than 11 otherwise freq will not fall */
+ if (ret != 1 || input < 11 || input > 100 ||
input >= dbs_tuners_ins.up_threshold) {
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return -EINVAL;
}
dbs_tuners_ins.down_threshold = input;
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
-static ssize_t store_ignore_nice(struct cpufreq_policy *policy,
+static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
const char *buf, size_t count)
{
unsigned int input;
int ret;
unsigned int j;
-
- ret = sscanf (buf, "%u", &input);
- if ( ret != 1 )
+
+ ret = sscanf(buf, "%u", &input);
+ if (ret != 1)
return -EINVAL;
- if ( input > 1 )
+ if (input > 1)
input = 1;
-
- down(&dbs_sem);
- if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
- up(&dbs_sem);
+
+ mutex_lock(&dbs_mutex);
+ if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
+ mutex_unlock(&dbs_mutex);
return count;
}
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;
}
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
{
unsigned int input;
int ret;
+ ret = sscanf(buf, "%u", &input);
- ret = sscanf (buf, "%u", &input);
-
- if ( ret != 1 )
+ if (ret != 1)
return -EINVAL;
- if ( input > 100 )
+ 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 :) */
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
dbs_tuners_ins.freq_step = input;
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
define_one_rw(sampling_down_factor);
define_one_rw(up_threshold);
define_one_rw(down_threshold);
-define_one_rw(ignore_nice);
+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,
&sampling_down_factor.attr,
&up_threshold.attr,
&down_threshold.attr,
- &ignore_nice.attr,
+ &ignore_nice_load.attr,
&freq_step.attr,
NULL
};
/************************** 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 freq_step;
- unsigned int freq_down_sampling_rate;
- static int down_skip[NR_CPUS];
- static int requested_freq[NR_CPUS];
- static unsigned short init_flag = 0;
- struct cpu_dbs_info_s *this_dbs_info;
- struct cpu_dbs_info_s *dbs_info;
+ unsigned int load = 0;
+ unsigned int freq_target;
struct cpufreq_policy *policy;
unsigned int j;
- this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
- if (!this_dbs_info->enable)
- return;
-
policy = this_dbs_info->cur_policy;
- if ( init_flag == 0 ) {
- for_each_online_cpu(j) {
- dbs_info = &per_cpu(cpu_dbs_info, j);
- requested_freq[j] = dbs_info->cur_policy->cur;
- }
- init_flag = 1;
- }
-
- /*
- * 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
+ * Any frequency increase takes it to the maximum frequency.
+ * Frequency reduction happens at minimum steps of
+ * 5% (default) of maximum frequency
*/
- /* Check for frequency increase */
-
- idle_ticks = UINT_MAX;
- for_each_cpu_mask(j, policy->cpus) {
- unsigned int tmp_idle_ticks, total_idle_ticks;
+ /* 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;
j_dbs_info = &per_cpu(cpu_dbs_info, j);
- /* Check for frequency increase */
- total_idle_ticks = get_cpu_idle_time(j);
- tmp_idle_ticks = total_idle_ticks -
- j_dbs_info->prev_cpu_idle_up;
- j_dbs_info->prev_cpu_idle_up = 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;
- up_idle_ticks = (100 - dbs_tuners_ins.up_threshold) *
- usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
+ cur_idle_time = get_cpu_idle_time(j, &cur_wall_time);
- if (idle_ticks < up_idle_ticks) {
- down_skip[cpu] = 0;
- for_each_cpu_mask(j, policy->cpus) {
- struct cpu_dbs_info_s *j_dbs_info;
+ wall_time = (unsigned int) cputime64_sub(cur_wall_time,
+ j_dbs_info->prev_cpu_wall);
+ j_dbs_info->prev_cpu_wall = cur_wall_time;
- j_dbs_info = &per_cpu(cpu_dbs_info, j);
- j_dbs_info->prev_cpu_idle_down =
- j_dbs_info->prev_cpu_idle_up;
+ 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;
+
+ /* Check for frequency increase */
+ if (load > dbs_tuners_ins.up_threshold) {
+ this_dbs_info->down_skip = 0;
+
/* if we are already at full speed then break out early */
- if (requested_freq[cpu] == policy->max)
+ if (this_dbs_info->requested_freq == policy->max)
return;
-
- freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
+
+ freq_target = (dbs_tuners_ins.freq_step * policy->max) / 100;
/* max freq cannot be less than 100. But who knows.... */
- if (unlikely(freq_step == 0))
- freq_step = 5;
-
- requested_freq[cpu] += freq_step;
- if (requested_freq[cpu] > policy->max)
- requested_freq[cpu] = policy->max;
-
- __cpufreq_driver_target(policy, requested_freq[cpu],
+ if (unlikely(freq_target == 0))
+ freq_target = 5;
+
+ this_dbs_info->requested_freq += freq_target;
+ if (this_dbs_info->requested_freq > policy->max)
+ this_dbs_info->requested_freq = policy->max;
+
+ __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
CPUFREQ_RELATION_H);
return;
}
- /* Check for frequency decrease */
- down_skip[cpu]++;
- if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
- 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;
- idle_ticks = UINT_MAX;
- for_each_cpu_mask(j, policy->cpus) {
- unsigned int tmp_idle_ticks, total_idle_ticks;
- struct cpu_dbs_info_s *j_dbs_info;
+ this_dbs_info->requested_freq -= freq_target;
+ if (this_dbs_info->requested_freq < policy->min)
+ this_dbs_info->requested_freq = policy->min;
- j_dbs_info = &per_cpu(cpu_dbs_info, j);
- total_idle_ticks = j_dbs_info->prev_cpu_idle_up;
- tmp_idle_ticks = total_idle_ticks -
- j_dbs_info->prev_cpu_idle_down;
- j_dbs_info->prev_cpu_idle_down = total_idle_ticks;
+ /*
+ * if we cannot reduce the frequency anymore, break out early
+ */
+ if (policy->cur == policy->min)
+ return;
- if (tmp_idle_ticks < idle_ticks)
- idle_ticks = tmp_idle_ticks;
+ __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
+ CPUFREQ_RELATION_H);
+ return;
}
+}
- /* Scale idle ticks by 100 and compare with up and down ticks */
- idle_ticks *= 100;
- down_skip[cpu] = 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_step to be zero */
- if (requested_freq[cpu] == policy->min
- || dbs_tuners_ins.freq_step == 0)
- return;
+static void do_dbs_timer(struct work_struct *work)
+{
+ struct cpu_dbs_info_s *dbs_info =
+ container_of(work, struct cpu_dbs_info_s, work.work);
+ unsigned int cpu = dbs_info->cpu;
- freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
+ /* We want all CPUs to do sampling nearly on same jiffy */
+ int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
- /* max freq cannot be less than 100. But who knows.... */
- if (unlikely(freq_step == 0))
- freq_step = 5;
+ delay -= jiffies % delay;
- requested_freq[cpu] -= freq_step;
- if (requested_freq[cpu] < policy->min)
- requested_freq[cpu] = policy->min;
+ if (lock_policy_rwsem_write(cpu) < 0)
+ return;
- __cpufreq_driver_target(policy,
- requested_freq[cpu],
- CPUFREQ_RELATION_H);
+ 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 void do_dbs_timer(void *data)
-{
- int i;
- down(&dbs_sem);
- for_each_online_cpu(i)
- dbs_check_cpu(i);
- schedule_delayed_work(&dbs_work,
- usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
- up(&dbs_sem);
-}
-
-static inline void dbs_timer_init(void)
+static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
{
- INIT_WORK(&dbs_work, do_dbs_timer, NULL);
- 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_sync(&dbs_info->work);
}
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
unsigned int cpu = policy->cpu;
struct cpu_dbs_info_s *this_dbs_info;
unsigned int j;
+ int rc;
this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
switch (event) {
case CPUFREQ_GOV_START:
- if ((!cpu_online(cpu)) ||
- (!policy->cur))
+ if ((!cpu_online(cpu)) || (!policy->cur))
return -EINVAL;
- if (policy->cpuinfo.transition_latency >
- (TRANSITION_LATENCY_LIMIT * 1000))
- return -EINVAL;
if (this_dbs_info->enable) /* Already enabled */
break;
-
- down(&dbs_sem);
- for_each_cpu_mask(j, policy->cpus) {
+
+ mutex_lock(&dbs_mutex);
+
+ rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
+ if (rc) {
+ mutex_unlock(&dbs_mutex);
+ return rc;
+ }
+
+ for_each_cpu(j, policy->cpus) {
struct cpu_dbs_info_s *j_dbs_info;
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(j);
- 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;
- sysfs_create_group(&policy->kobj, &dbs_attr_group);
+ this_dbs_info->down_skip = 0;
+ this_dbs_info->requested_freq = policy->cur;
+
dbs_enable++;
/*
* Start the timerschedule work, when this governor
if (dbs_enable == 1) {
unsigned int latency;
/* policy latency is in nS. Convert it to uS first */
+ latency = policy->cpuinfo.transition_latency / 1000;
+ if (latency == 0)
+ latency = 1;
- latency = policy->cpuinfo.transition_latency;
- if (latency < 1000)
- latency = 1000;
+ def_sampling_rate =
+ max(latency * LATENCY_MULTIPLIER,
+ MIN_STAT_SAMPLING_RATE);
- def_sampling_rate = (latency / 1000) *
- DEF_SAMPLING_RATE_LATENCY_MULTIPLIER;
dbs_tuners_ins.sampling_rate = def_sampling_rate;
- dbs_tuners_ins.ignore_nice = 0;
- dbs_tuners_ins.freq_step = 5;
- dbs_timer_init();
+ cpufreq_register_notifier(
+ &dbs_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
}
-
- up(&dbs_sem);
+ dbs_timer_init(this_dbs_info);
+
+ mutex_unlock(&dbs_mutex);
+
break;
case CPUFREQ_GOV_STOP:
- down(&dbs_sem);
- this_dbs_info->enable = 0;
+ mutex_lock(&dbs_mutex);
+ 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();
-
- up(&dbs_sem);
+ if (dbs_enable == 0)
+ cpufreq_unregister_notifier(
+ &dbs_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ mutex_unlock(&dbs_mutex);
break;
case CPUFREQ_GOV_LIMITS:
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
if (policy->max < this_dbs_info->cur_policy->cur)
__cpufreq_driver_target(
this_dbs_info->cur_policy,
- policy->max, CPUFREQ_RELATION_H);
+ policy->max, CPUFREQ_RELATION_H);
else if (policy->min > this_dbs_info->cur_policy->cur)
__cpufreq_driver_target(
this_dbs_info->cur_policy,
- policy->min, CPUFREQ_RELATION_L);
- up(&dbs_sem);
+ policy->min, CPUFREQ_RELATION_L);
+ mutex_unlock(&dbs_mutex);
+
break;
}
return 0;
}
-static struct cpufreq_governor cpufreq_gov_dbs = {
- .name = "conservative",
- .governor = cpufreq_governor_dbs,
- .owner = THIS_MODULE,
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE
+static
+#endif
+struct cpufreq_governor cpufreq_gov_conservative = {
+ .name = "conservative",
+ .governor = cpufreq_governor_dbs,
+ .max_transition_latency = TRANSITION_LATENCY_LIMIT,
+ .owner = THIS_MODULE,
};
static int __init cpufreq_gov_dbs_init(void)
{
- return cpufreq_register_governor(&cpufreq_gov_dbs);
+ 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_dbs);
+ 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);
+#else
module_init(cpufreq_gov_dbs_init);
+#endif
module_exit(cpufreq_gov_dbs_exit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff