#include <linux/types.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
-#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/kmod.h>
#include <linux/workqueue.h>
*/
#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
* 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 (MIN_SAMPLING_RATE_RATIO * jiffies_to_usecs(10))
-#define MIN_SAMPLING_RATE (def_sampling_rate / MIN_SAMPLING_RATE_RATIO)
+#define MIN_SAMPLING_RATE (def_sampling_rate / 2)
#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 DEF_SAMPLING_RATE_LATENCY_MULTIPLIER (100000)
+#define DEF_SAMPLING_DOWN_FACTOR (5)
#define TRANSITION_LATENCY_LIMIT (10 * 1000)
static void do_dbs_timer(void *data);
unsigned int prev_cpu_idle_up;
unsigned int prev_cpu_idle_down;
unsigned int enable;
- unsigned int down_skip;
- unsigned int requested_freq;
};
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 DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
.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)
unsigned int input;
int ret;
ret = sscanf (buf, "%u", &input);
- if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+ if (ret != 1 )
return -EINVAL;
mutex_lock(&dbs_mutex);
ret = sscanf (buf, "%u", &input);
mutex_lock(&dbs_mutex);
- if (ret != 1 || input > 100 || input <= dbs_tuners_ins.down_threshold) {
+ if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
+ input < MIN_FREQUENCY_UP_THRESHOLD ||
+ input <= dbs_tuners_ins.down_threshold) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
}
ret = sscanf (buf, "%u", &input);
mutex_lock(&dbs_mutex);
- if (ret != 1 || input > 100 || input >= dbs_tuners_ins.up_threshold) {
+ if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD ||
+ input < MIN_FREQUENCY_DOWN_THRESHOLD ||
+ input >= dbs_tuners_ins.up_threshold) {
mutex_unlock(&dbs_mutex);
return -EINVAL;
}
static void dbs_check_cpu(int cpu)
{
unsigned int idle_ticks, up_idle_ticks, down_idle_ticks;
- unsigned int tmp_idle_ticks, total_idle_ticks;
unsigned int freq_step;
unsigned int freq_down_sampling_rate;
- struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ 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;
+
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
*/
/* Check for frequency increase */
- idle_ticks = UINT_MAX;
- /* 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;
+ 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;
- if (tmp_idle_ticks < idle_ticks)
- idle_ticks = tmp_idle_ticks;
+ 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);
+ usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
if (idle_ticks < up_idle_ticks) {
- this_dbs_info->down_skip = 0;
- this_dbs_info->prev_cpu_idle_down =
- this_dbs_info->prev_cpu_idle_up;
+ 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 (this_dbs_info->requested_freq == policy->max)
+ if (requested_freq[cpu] == policy->max)
return;
freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
if (unlikely(freq_step == 0))
freq_step = 5;
- this_dbs_info->requested_freq += freq_step;
- if (this_dbs_info->requested_freq > policy->max)
- this_dbs_info->requested_freq = policy->max;
+ requested_freq[cpu] += freq_step;
+ if (requested_freq[cpu] > policy->max)
+ requested_freq[cpu] = policy->max;
- __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
+ __cpufreq_driver_target(policy, requested_freq[cpu],
CPUFREQ_RELATION_H);
return;
}
/* Check for frequency decrease */
- this_dbs_info->down_skip++;
- if (this_dbs_info->down_skip < dbs_tuners_ins.sampling_down_factor)
+ down_skip[cpu]++;
+ if (down_skip[cpu] < 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;
+ 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);
+ 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;
+ 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;
+ 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);
+ 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
+ /* 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 (this_dbs_info->requested_freq == policy->min
+ * freq_step to be zero */
+ if (requested_freq[cpu] == policy->min
|| dbs_tuners_ins.freq_step == 0)
return;
if (unlikely(freq_step == 0))
freq_step = 5;
- this_dbs_info->requested_freq -= freq_step;
- if (this_dbs_info->requested_freq < policy->min)
- this_dbs_info->requested_freq = policy->min;
+ requested_freq[cpu] -= freq_step;
+ if (requested_freq[cpu] < policy->min)
+ requested_freq[cpu] = policy->min;
- __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
- CPUFREQ_RELATION_H);
+ __cpufreq_driver_target(policy,
+ requested_freq[cpu],
+ CPUFREQ_RELATION_H);
return;
}
}
static void do_dbs_timer(void *data)
{
int i;
- lock_cpu_hotplug();
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);
- unlock_cpu_hotplug();
}
static inline void dbs_timer_init(void)
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_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;
- this_dbs_info->down_skip = 0;
- this_dbs_info->requested_freq = policy->cur;
sysfs_create_group(&policy->kobj, &dbs_attr_group);
dbs_enable++;
/*
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;
-
- 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;
+ latency = policy->cpuinfo.transition_latency;
+ if (latency < 1000)
+ latency = 1000;
+ 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();
}
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