#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/cpu.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/jiffies.h>
#include <linux/kernel_stat.h>
+#include <linux/percpu.h>
#include <linux/mutex.h>
/*
#define MIN_FREQUENCY_UP_THRESHOLD (11)
#define MAX_FREQUENCY_UP_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;
+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)
#define MAX_SAMPLING_RATE (500 * def_sampling_rate)
#define DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (1000)
+#define DEF_SAMPLING_DOWN_FACTOR (1)
+#define MAX_SAMPLING_DOWN_FACTOR (10)
#define TRANSITION_LATENCY_LIMIT (10 * 1000)
static void do_dbs_timer(void *data);
struct cpu_dbs_info_s {
- cputime64_t prev_cpu_idle;
- cputime64_t prev_cpu_wall;
- struct cpufreq_policy *cur_policy;
- struct work_struct work;
- unsigned int enable;
+ struct cpufreq_policy *cur_policy;
+ unsigned int prev_cpu_idle_up;
+ unsigned int prev_cpu_idle_down;
+ unsigned int enable;
};
static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
static unsigned int dbs_enable; /* number of CPUs using this policy */
-/*
- * 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
- */
-static DEFINE_MUTEX(dbs_mutex);
-
-static struct workqueue_struct *kondemand_wq;
+static DEFINE_MUTEX (dbs_mutex);
+static DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
struct dbs_tuners {
- unsigned int sampling_rate;
- unsigned int up_threshold;
- unsigned int ignore_nice;
+ unsigned int sampling_rate;
+ unsigned int sampling_down_factor;
+ unsigned int up_threshold;
+ unsigned int ignore_nice;
};
static struct dbs_tuners dbs_tuners_ins = {
- .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
- .ignore_nice = 0,
+ .up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
+ .sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
};
-static inline cputime64_t get_cpu_idle_time(unsigned int cpu)
+static inline unsigned int get_cpu_idle_time(unsigned int cpu)
{
- cputime64_t retval;
-
- retval = cputime64_add(kstat_cpu(cpu).cpustat.idle,
- kstat_cpu(cpu).cpustat.iowait);
-
- if (dbs_tuners_ins.ignore_nice)
- retval = cputime64_add(retval, kstat_cpu(cpu).cpustat.nice);
-
- return retval;
+ return kstat_cpu(cpu).cpustat.idle +
+ kstat_cpu(cpu).cpustat.iowait +
+ ( dbs_tuners_ins.ignore_nice ?
+ kstat_cpu(cpu).cpustat.nice :
+ 0);
}
/************************** sysfs interface ************************/
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);
return sprintf(buf, "%u\n", dbs_tuners_ins.object); \
}
show_one(sampling_rate, sampling_rate);
+show_one(sampling_down_factor, sampling_down_factor);
show_one(up_threshold, up_threshold);
show_one(ignore_nice_load, ignore_nice);
-static ssize_t store_sampling_rate(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 )
+ return -EINVAL;
+
+ if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+ return -EINVAL;
+
+ mutex_lock(&dbs_mutex);
+ dbs_tuners_ins.sampling_down_factor = input;
+ mutex_unlock(&dbs_mutex);
+
+ return count;
+}
+
+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);
mutex_lock(&dbs_mutex);
if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
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);
mutex_lock(&dbs_mutex);
- if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
+ if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
input < MIN_FREQUENCY_UP_THRESHOLD) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
int ret;
unsigned int j;
-
- ret = sscanf(buf, "%u", &input);
+
+ ret = sscanf (buf, "%u", &input);
if ( ret != 1 )
return -EINVAL;
if ( input > 1 )
input = 1;
-
+
mutex_lock(&dbs_mutex);
if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
mutex_unlock(&dbs_mutex);
}
dbs_tuners_ins.ignore_nice = input;
- /* we need to re-evaluate prev_cpu_idle */
+ /* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
for_each_online_cpu(j) {
- 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 = get_jiffies_64();
+ 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;
}
mutex_unlock(&dbs_mutex);
__ATTR(_name, 0644, show_##_name, store_##_name)
define_one_rw(sampling_rate);
+define_one_rw(sampling_down_factor);
define_one_rw(up_threshold);
define_one_rw(ignore_nice_load);
&sampling_rate_max.attr,
&sampling_rate_min.attr,
&sampling_rate.attr,
+ &sampling_down_factor.attr,
&up_threshold.attr,
&ignore_nice_load.attr,
NULL
/************************** sysfs end ************************/
-static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
+static void dbs_check_cpu(int cpu)
{
- unsigned int idle_ticks, total_ticks;
- unsigned int load;
- cputime64_t cur_jiffies;
+ unsigned int idle_ticks, up_idle_ticks, total_ticks;
+ unsigned int freq_next;
+ unsigned int freq_down_sampling_rate;
+ static int down_skip[NR_CPUS];
+ struct cpu_dbs_info_s *this_dbs_info;
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;
- cur_jiffies = jiffies64_to_cputime64(get_jiffies_64());
- total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
- this_dbs_info->prev_cpu_wall);
- this_dbs_info->prev_cpu_wall = cur_jiffies;
- if (!total_ticks)
- return;
- /*
+ /*
* Every sampling_rate, we check, if current idle time is less
* than 20% (default), then we try to increase frequency
- * Every sampling_rate, we look for a the lowest
+ * Every sampling_rate*sampling_down_factor, we look for a the lowest
* frequency which can sustain the load while keeping idle time over
* 30%. If such a frequency exist, we try to decrease to this frequency.
*
- * Any frequency increase takes it to the maximum frequency.
- * Frequency reduction happens at minimum steps of
- * 5% (default) of current frequency
+ * Any frequency increase takes it to the maximum frequency.
+ * Frequency reduction happens at minimum steps of
+ * 5% (default) of current frequency
*/
- /* Get Idle Time */
+ /* Check for frequency increase */
idle_ticks = UINT_MAX;
for_each_cpu_mask(j, policy->cpus) {
- cputime64_t total_idle_ticks;
- unsigned int tmp_idle_ticks;
+ unsigned int tmp_idle_ticks, total_idle_ticks;
struct cpu_dbs_info_s *j_dbs_info;
j_dbs_info = &per_cpu(cpu_dbs_info, j);
total_idle_ticks = get_cpu_idle_time(j);
- tmp_idle_ticks = (unsigned int) cputime64_sub(total_idle_ticks,
- j_dbs_info->prev_cpu_idle);
- j_dbs_info->prev_cpu_idle = total_idle_ticks;
+ 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;
}
- load = (100 * (total_ticks - idle_ticks)) / total_ticks;
- /* Check for frequency increase */
- if (load > dbs_tuners_ins.up_threshold) {
+ /* 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);
+
+ 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;
+
+ j_dbs_info = &per_cpu(cpu_dbs_info, j);
+ j_dbs_info->prev_cpu_idle_down =
+ j_dbs_info->prev_cpu_idle_up;
+ }
/* if we are already at full speed then break out early */
if (policy->cur == policy->max)
return;
-
- __cpufreq_driver_target(policy, policy->max,
+
+ __cpufreq_driver_target(policy, policy->max,
CPUFREQ_RELATION_H);
return;
}
/* Check for frequency decrease */
+ down_skip[cpu]++;
+ if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
+ return;
+
+ 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;
+
+ j_dbs_info = &per_cpu(cpu_dbs_info, j);
+ /* Check for frequency decrease */
+ 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 (tmp_idle_ticks < idle_ticks)
+ idle_ticks = tmp_idle_ticks;
+ }
+
+ down_skip[cpu] = 0;
/* if we cannot reduce the frequency anymore, break out early */
if (policy->cur == policy->min)
return;
+ /* Compute how many ticks there are between two measurements */
+ freq_down_sampling_rate = dbs_tuners_ins.sampling_rate *
+ dbs_tuners_ins.sampling_down_factor;
+ total_ticks = usecs_to_jiffies(freq_down_sampling_rate);
+
/*
* 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.up_threshold - 10)) {
- unsigned int freq_next;
- freq_next = (policy->cur * load) /
+ freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks;
+ freq_next = (freq_next * policy->cur) /
(dbs_tuners_ins.up_threshold - 10);
+ if (freq_next <= ((policy->cur * 95) / 100))
__cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
- }
}
static void do_dbs_timer(void *data)
-{
- unsigned int cpu = smp_processor_id();
- struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
-
- if (!dbs_info->enable)
- return;
-
- lock_cpu_hotplug();
- dbs_check_cpu(dbs_info);
- unlock_cpu_hotplug();
- queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->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);
+}
-static inline void dbs_timer_init(unsigned int cpu)
+static inline void dbs_timer_init(void)
{
- struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
-
- INIT_WORK(&dbs_info->work, do_dbs_timer, 0);
- queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,
+ INIT_WORK(&dbs_work, do_dbs_timer, NULL);
+ schedule_delayed_work(&dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
return;
}
-static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
+static inline void dbs_timer_exit(void)
{
- dbs_info->enable = 0;
- cancel_delayed_work(&dbs_info->work);
- flush_workqueue(kondemand_wq);
+ cancel_delayed_work(&dbs_work);
+ return;
}
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
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)) {
- printk(KERN_WARNING "ondemand governor failed to load "
- "due to too long transition latency\n");
+ (TRANSITION_LATENCY_LIMIT * 1000))
return -EINVAL;
- }
if (this_dbs_info->enable) /* Already enabled */
break;
-
+
mutex_lock(&dbs_mutex);
- dbs_enable++;
- if (dbs_enable == 1) {
- kondemand_wq = create_workqueue("kondemand");
- if (!kondemand_wq) {
- printk(KERN_ERR "Creation of kondemand failed\n");
- dbs_enable--;
- mutex_unlock(&dbs_mutex);
- return -ENOSPC;
- }
- }
for_each_cpu_mask(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 = get_cpu_idle_time(j);
- j_dbs_info->prev_cpu_wall = get_jiffies_64();
+
+ 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;
}
this_dbs_info->enable = 1;
sysfs_create_group(&policy->kobj, &dbs_attr_group);
+ dbs_enable++;
/*
* Start the timerschedule work, when this governor
* is used for first time
def_sampling_rate = MIN_STAT_SAMPLING_RATE;
dbs_tuners_ins.sampling_rate = def_sampling_rate;
- }
- dbs_timer_init(policy->cpu);
+ dbs_tuners_ins.ignore_nice = 0;
+ dbs_timer_init();
+ }
+
mutex_unlock(&dbs_mutex);
break;
case CPUFREQ_GOV_STOP:
mutex_lock(&dbs_mutex);
- dbs_timer_exit(this_dbs_info);
+ this_dbs_info->enable = 0;
sysfs_remove_group(&policy->kobj, &dbs_attr_group);
dbs_enable--;
- if (dbs_enable == 0)
- destroy_workqueue(kondemand_wq);
-
+ /*
+ * Stop the timerschedule work, when this governor
+ * is used for first time
+ */
+ if (dbs_enable == 0)
+ dbs_timer_exit();
+
mutex_unlock(&dbs_mutex);
break;
case CPUFREQ_GOV_LIMITS:
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);
+ __cpufreq_driver_target(
+ this_dbs_info->cur_policy,
+ 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);
+ __cpufreq_driver_target(
+ this_dbs_info->cur_policy,
+ policy->min, CPUFREQ_RELATION_L);
mutex_unlock(&dbs_mutex);
break;
}
}
static struct cpufreq_governor cpufreq_gov_dbs = {
- .name = "ondemand",
- .governor = cpufreq_governor_dbs,
- .owner = THIS_MODULE,
+ .name = "ondemand",
+ .governor = cpufreq_governor_dbs,
+ .owner = THIS_MODULE,
};
static int __init cpufreq_gov_dbs_init(void)
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);
}
-MODULE_AUTHOR("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
-MODULE_AUTHOR("Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>");
-MODULE_DESCRIPTION("'cpufreq_ondemand' - A dynamic cpufreq governor for "
- "Low Latency Frequency Transition capable processors");
-MODULE_LICENSE("GPL");
+MODULE_AUTHOR ("Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>");
+MODULE_DESCRIPTION ("'cpufreq_ondemand' - A dynamic cpufreq governor for "
+ "Low Latency Frequency Transition capable processors");
+MODULE_LICENSE ("GPL");
module_init(cpufreq_gov_dbs_init);
module_exit(cpufreq_gov_dbs_exit);
git://git.onelab.eu / linux-2.6.git / blobdiff