*/
#define DEF_FREQUENCY_UP_THRESHOLD (80)
-#define MIN_FREQUENCY_UP_THRESHOLD (0)
+#define MIN_FREQUENCY_UP_THRESHOLD (11)
#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 processor. Default polling frequency is 1000 times the transition
* 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 (1000)
-#define DEF_SAMPLING_DOWN_FACTOR (10)
+#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);
unsigned int sampling_rate;
unsigned int sampling_down_factor;
unsigned int up_threshold;
- unsigned int down_threshold;
unsigned int ignore_nice;
};
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 inline unsigned int get_cpu_idle_time(unsigned int cpu)
+{
+ return kstat_cpu(cpu).cpustat.idle +
+ kstat_cpu(cpu).cpustat.iowait +
+ ( dbs_tuners_ins.ignore_nice ?
+ kstat_cpu(cpu).cpustat.nice :
+ 0);
+}
+
/************************** sysfs interface ************************/
static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
{
show_one(sampling_rate, sampling_rate);
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);
static ssize_t store_sampling_down_factor(struct cpufreq_policy *unused,
const char *buf, size_t count)
if (ret != 1 )
return -EINVAL;
+ if (input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
+ return -EINVAL;
+
down(&dbs_sem);
dbs_tuners_ins.sampling_down_factor = input;
up(&dbs_sem);
down(&dbs_sem);
if (ret != 1 || input > MAX_FREQUENCY_UP_THRESHOLD ||
- input < MIN_FREQUENCY_UP_THRESHOLD ||
- input <= dbs_tuners_ins.down_threshold) {
+ input < MIN_FREQUENCY_UP_THRESHOLD) {
up(&dbs_sem);
return -EINVAL;
}
return count;
}
-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);
-
- down(&dbs_sem);
- if (ret != 1 || input > MAX_FREQUENCY_DOWN_THRESHOLD ||
- input < MIN_FREQUENCY_DOWN_THRESHOLD ||
- input >= dbs_tuners_ins.up_threshold) {
- up(&dbs_sem);
- return -EINVAL;
- }
-
- dbs_tuners_ins.down_threshold = input;
- up(&dbs_sem);
-
- 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;
dbs_tuners_ins.ignore_nice = input;
/* we need to re-evaluate prev_cpu_idle_up and prev_cpu_idle_down */
- for_each_cpu_mask(j, policy->cpus) {
+ 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->cur_policy = policy;
-
- j_dbs_info->prev_cpu_idle_up =
- kstat_cpu(j).cpustat.idle +
- kstat_cpu(j).cpustat.iowait +
- ( !dbs_tuners_ins.ignore_nice
- ? kstat_cpu(j).cpustat.nice : 0 );
+ 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);
define_one_rw(sampling_rate);
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);
static struct attribute * dbs_attributes[] = {
&sampling_rate_max.attr,
&sampling_rate.attr,
&sampling_down_factor.attr,
&up_threshold.attr,
- &down_threshold.attr,
- &ignore_nice.attr,
+ &ignore_nice_load.attr,
NULL
};
static void dbs_check_cpu(int cpu)
{
- unsigned int idle_ticks, up_idle_ticks, down_idle_ticks;
- unsigned int total_idle_ticks;
- unsigned int freq_down_step;
+ 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;
policy = this_dbs_info->cur_policy;
/*
- * 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 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% of max_frequency
+ * 5% (default) of current frequency
*/
/* Check for frequency increase */
- total_idle_ticks = kstat_cpu(cpu).cpustat.idle +
- kstat_cpu(cpu).cpustat.iowait;
- /* consider 'nice' tasks as 'idle' time too if required */
- if (dbs_tuners_ins.ignore_nice == 0)
- total_idle_ticks += kstat_cpu(cpu).cpustat.nice;
- 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;
+ unsigned int tmp_idle_ticks, total_idle_ticks;
struct cpu_dbs_info_s *j_dbs_info;
- if (j == cpu)
- continue;
-
j_dbs_info = &per_cpu(cpu_dbs_info, j);
- /* Check for frequency increase */
- total_idle_ticks = kstat_cpu(j).cpustat.idle +
- kstat_cpu(j).cpustat.iowait;
- /* consider 'nice' too? */
- if (dbs_tuners_ins.ignore_nice == 0)
- total_idle_ticks += kstat_cpu(j).cpustat.nice;
+ 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;
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_RELATION_H);
- down_skip[cpu] = 0;
- this_dbs_info->prev_cpu_idle_down = total_idle_ticks;
return;
}
if (down_skip[cpu] < dbs_tuners_ins.sampling_down_factor)
return;
- total_idle_ticks = kstat_cpu(cpu).cpustat.idle +
- kstat_cpu(cpu).cpustat.iowait;
- /* consider 'nice' too? */
- if (dbs_tuners_ins.ignore_nice == 0)
- total_idle_ticks += kstat_cpu(cpu).cpustat.nice;
- 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;
+ unsigned int tmp_idle_ticks, total_idle_ticks;
struct cpu_dbs_info_s *j_dbs_info;
- if (j == cpu)
- continue;
-
j_dbs_info = &per_cpu(cpu_dbs_info, j);
- /* Check for frequency increase */
- total_idle_ticks = kstat_cpu(j).cpustat.idle +
- kstat_cpu(j).cpustat.iowait;
- /* consider 'nice' too? */
- if (dbs_tuners_ins.ignore_nice == 0)
- total_idle_ticks += kstat_cpu(j).cpustat.nice;
+ /* 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;
idle_ticks = tmp_idle_ticks;
}
- /* Scale idle ticks by 100 and compare with up and down ticks */
- idle_ticks *= 100;
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;
- 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 */
- if (policy->cur == policy->min)
- return;
-
- freq_down_step = (5 * policy->max) / 100;
+ total_ticks = usecs_to_jiffies(freq_down_sampling_rate);
- /* max freq cannot be less than 100. But who knows.... */
- if (unlikely(freq_down_step == 0))
- freq_down_step = 5;
+ /*
+ * 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.
+ */
+ freq_next = ((total_ticks - idle_ticks) * 100) / total_ticks;
+ freq_next = (freq_next * policy->cur) /
+ (dbs_tuners_ins.up_threshold - 10);
- __cpufreq_driver_target(policy,
- policy->cur - freq_down_step,
- CPUFREQ_RELATION_H);
- return;
- }
+ if (freq_next <= ((policy->cur * 95) / 100))
+ __cpufreq_driver_target(policy, freq_next, CPUFREQ_RELATION_L);
}
static void do_dbs_timer(void *data)
j_dbs_info = &per_cpu(cpu_dbs_info, j);
j_dbs_info->cur_policy = policy;
- j_dbs_info->prev_cpu_idle_up =
- kstat_cpu(j).cpustat.idle +
- kstat_cpu(j).cpustat.iowait +
- ( !dbs_tuners_ins.ignore_nice
- ? kstat_cpu(j).cpustat.nice : 0 );
+ 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;
}
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 = 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;
projects / linux-2.6-omap-h63xx.git / blobdiff