#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
* 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 (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 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;
+ 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);
+static DECLARE_DELAYED_WORK(dbs_work, do_dbs_timer);
struct dbs_tuners {
unsigned int sampling_rate;
.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)
{
- return kstat_cpu(cpu).cpustat.idle +
+ unsigned int add_nice = 0, ret;
+
+ if (dbs_tuners_ins.ignore_nice)
+ add_nice = kstat_cpu(cpu).cpustat.nice;
+
+ ret = kstat_cpu(cpu).cpustat.idle +
kstat_cpu(cpu).cpustat.iowait +
- ( dbs_tuners_ins.ignore_nice ?
- kstat_cpu(cpu).cpustat.nice :
- 0);
+ add_nice;
+
+ return ret;
}
/************************** sysfs interface ************************/
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;
mutex_lock(&dbs_mutex);
ret = sscanf (buf, "%u", &input);
mutex_lock(&dbs_mutex);
- if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
- input < MIN_FREQUENCY_UP_THRESHOLD ||
- input <= dbs_tuners_ins.down_threshold) {
+ if (ret != 1 || input > 100 || 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 > MAX_FREQUENCY_DOWN_THRESHOLD ||
- input < MIN_FREQUENCY_DOWN_THRESHOLD ||
- input >= dbs_tuners_ins.up_threshold) {
+ if (ret != 1 || input > 100 || 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;
- 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 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;
- }
- init_flag = 1;
- }
-
/*
* 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->down_skip = 0;
+ 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)
+ if (this_dbs_info->requested_freq == policy->max)
return;
freq_step = (dbs_tuners_ins.freq_step * policy->max) / 100;
if (unlikely(freq_step == 0))
freq_step = 5;
- requested_freq[cpu] += freq_step;
- if (requested_freq[cpu] > policy->max)
- requested_freq[cpu] = policy->max;
+ this_dbs_info->requested_freq += freq_step;
+ if (this_dbs_info->requested_freq > policy->max)
+ this_dbs_info->requested_freq = policy->max;
- __cpufreq_driver_target(policy, requested_freq[cpu],
+ __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)
+ this_dbs_info->down_skip++;
+ if (this_dbs_info->down_skip < 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;
- down_skip[cpu] = 0;
+ 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);
+ 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 (requested_freq[cpu] == policy->min
+ * freq_step to be zero
+ */
+ if (this_dbs_info->requested_freq == policy->min
|| dbs_tuners_ins.freq_step == 0)
return;
if (unlikely(freq_step == 0))
freq_step = 5;
- requested_freq[cpu] -= freq_step;
- if (requested_freq[cpu] < policy->min)
- requested_freq[cpu] = policy->min;
+ this_dbs_info->requested_freq -= freq_step;
+ if (this_dbs_info->requested_freq < policy->min)
+ this_dbs_info->requested_freq = policy->min;
- __cpufreq_driver_target(policy,
- requested_freq[cpu],
- CPUFREQ_RELATION_H);
+ __cpufreq_driver_target(policy, this_dbs_info->requested_freq,
+ CPUFREQ_RELATION_H);
return;
}
}
-static void do_dbs_timer(void *data)
+static void do_dbs_timer(struct work_struct *work)
{
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)
{
- INIT_WORK(&dbs_work, do_dbs_timer, NULL);
schedule_delayed_work(&dbs_work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
return;
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);
break;
mutex_lock(&dbs_mutex);
+
+ rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
+ if (rc) {
+ mutex_unlock(&dbs_mutex);
+ return rc;
+ }
+
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;
}
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 = (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();
}
git://git.onelab.eu / linux-2.6.git / blobdiff