#include <linux/jiffies.h>
#include <linux/kernel_stat.h>
#include <linux/percpu.h>
-
+#include <linux/mutex.h>
/*
* dbs is used in this file as a shortform for demandbased switching
* It helps to keep variable names smaller, simpler
*/
#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 (def_sampling_rate / 2)
+#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 (100000)
-#define DEF_SAMPLING_DOWN_FACTOR (5)
+#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);
static unsigned int dbs_enable; /* number of CPUs using this policy */
-static DECLARE_MUTEX (dbs_sem);
+static DEFINE_MUTEX (dbs_mutex);
static DECLARE_WORK (dbs_work, do_dbs_timer, NULL);
struct dbs_tuners {
unsigned int input;
int ret;
ret = sscanf (buf, "%u", &input);
- if (ret != 1 )
+ 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;
}
int ret;
ret = sscanf (buf, "%u", &input);
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
if (ret != 1 || input > MAX_SAMPLING_RATE || input < MIN_SAMPLING_RATE) {
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return -EINVAL;
}
dbs_tuners_ins.sampling_rate = input;
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
int ret;
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 < 0 ||
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;
}
int ret;
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);
+ if (ret != 1 || input > 100 || input < 0 ||
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;
}
if ( input > 1 )
input = 1;
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
if ( input == dbs_tuners_ins.ignore_nice ) { /* nothing to do */
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
dbs_tuners_ins.ignore_nice = input;
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;
}
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
return count;
}
/* 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;
}
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;
- 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;
-
+ static unsigned short down_skip[NR_CPUS];
+ static unsigned int requested_freq[NR_CPUS];
+ static unsigned int init_flag = NR_CPUS;
+ struct cpu_dbs_info_s *this_dbs_info = &per_cpu(cpu_dbs_info, cpu);
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;
+ if ( init_flag != 0 ) {
+ for_each_cpu(init_flag) {
+ down_skip[init_flag] = 0;
+ /* I doubt a CPU exists with a freq of 0hz :) */
+ requested_freq[init_flag] = 0;
}
- init_flag = 1;
+ init_flag = 0;
}
+ /*
+ * If its a freshly initialised cpu we setup requested_freq. This
+ * check could be avoided if we did not care about a first time
+ * stunted increase in CPU speed when there is a load. I feel we
+ * should be initialising this to something. The removal of a CPU
+ * is not a problem, after a short time the CPU should settle down
+ * to a 'natural' frequency.
+ */
+ if (requested_freq[cpu] == 0)
+ requested_freq[cpu] = this_dbs_info->cur_policy->cur;
+
+ policy = this_dbs_info->cur_policy;
+
/*
* The default safe range is 20% to 80%
* Every sampling_rate, we check
*/
/* Check for frequency increase */
-
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 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;
- }
+ /* 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;
+
+ 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) {
down_skip[cpu] = 0;
- for_each_cpu_mask(j, policy->cpus) {
- struct cpu_dbs_info_s *j_dbs_info;
+ this_dbs_info->prev_cpu_idle_down =
+ this_dbs_info->prev_cpu_idle_up;
- 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 (requested_freq[cpu] == policy->max)
return;
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);
- 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;
+ /* 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;
- }
+ 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;
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 */
+ * freq_step to be zero
+ */
if (requested_freq[cpu] == policy->min
|| dbs_tuners_ins.freq_step == 0)
return;
if (requested_freq[cpu] < policy->min)
requested_freq[cpu] = policy->min;
- __cpufreq_driver_target(policy,
- requested_freq[cpu],
- CPUFREQ_RELATION_H);
+ __cpufreq_driver_target(policy, requested_freq[cpu],
+ CPUFREQ_RELATION_H);
return;
}
}
static void do_dbs_timer(void *data)
{
int i;
- down(&dbs_sem);
+ 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));
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
}
static inline void dbs_timer_init(void)
if (this_dbs_info->enable) /* Already enabled */
break;
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
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_up = get_cpu_idle_time(j);
+ 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;
}
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 = (latency / 1000) *
+ 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;
+
dbs_tuners_ins.sampling_rate = def_sampling_rate;
dbs_tuners_ins.ignore_nice = 0;
dbs_tuners_ins.freq_step = 5;
dbs_timer_init();
}
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
break;
case CPUFREQ_GOV_STOP:
- down(&dbs_sem);
+ mutex_lock(&dbs_mutex);
this_dbs_info->enable = 0;
sysfs_remove_group(&policy->kobj, &dbs_attr_group);
dbs_enable--;
if (dbs_enable == 0)
dbs_timer_exit();
- up(&dbs_sem);
+ 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,
__cpufreq_driver_target(
this_dbs_info->cur_policy,
policy->min, CPUFREQ_RELATION_L);
- up(&dbs_sem);
+ mutex_unlock(&dbs_mutex);
break;
}
return 0;
projects / powerpc.git / blobdiff