cpufreq: ondemand: Replace down_differential tuner with adj_up_threshold

In order to avoid the calculation of up_threshold - down_differential
every time that the frequency must be decreased, we replace the
down_differential tuner with the adj_up_threshold which keeps the
difference across multiple checks.

Update the adj_up_threshold only when the up_theshold is also updated.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Stratos Karafotis 2013-02-06 13:34:00 +01:00 committed by Rafael J. Wysocki
parent df18e504aa
commit 4bd4e42819
2 changed files with 11 additions and 7 deletions

View File

@ -109,7 +109,7 @@ struct od_dbs_tuners {
unsigned int sampling_rate;
unsigned int sampling_down_factor;
unsigned int up_threshold;
unsigned int down_differential;
unsigned int adj_up_threshold;
unsigned int powersave_bias;
unsigned int io_is_busy;
};

View File

@ -47,7 +47,8 @@ static struct cpufreq_governor cpufreq_gov_ondemand;
static struct od_dbs_tuners od_tuners = {
.up_threshold = DEF_FREQUENCY_UP_THRESHOLD,
.sampling_down_factor = DEF_SAMPLING_DOWN_FACTOR,
.down_differential = DEF_FREQUENCY_DOWN_DIFFERENTIAL,
.adj_up_threshold = DEF_FREQUENCY_UP_THRESHOLD -
DEF_FREQUENCY_DOWN_DIFFERENTIAL,
.ignore_nice = 0,
.powersave_bias = 0,
};
@ -192,11 +193,9 @@ static void od_check_cpu(int cpu, unsigned int load_freq)
* support the current CPU usage without triggering the up policy. To be
* safe, we focus 10 points under the threshold.
*/
if (load_freq < (od_tuners.up_threshold - od_tuners.down_differential) *
policy->cur) {
if (load_freq < od_tuners.adj_up_threshold * policy->cur) {
unsigned int freq_next;
freq_next = load_freq / (od_tuners.up_threshold -
od_tuners.down_differential);
freq_next = load_freq / od_tuners.adj_up_threshold;
/* No longer fully busy, reset rate_mult */
dbs_info->rate_mult = 1;
@ -359,6 +358,10 @@ static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
input < MIN_FREQUENCY_UP_THRESHOLD) {
return -EINVAL;
}
/* Calculate the new adj_up_threshold */
od_tuners.adj_up_threshold += input;
od_tuners.adj_up_threshold -= od_tuners.up_threshold;
od_tuners.up_threshold = input;
return count;
}
@ -515,7 +518,8 @@ static int __init cpufreq_gov_dbs_init(void)
if (idle_time != -1ULL) {
/* Idle micro accounting is supported. Use finer thresholds */
od_tuners.up_threshold = MICRO_FREQUENCY_UP_THRESHOLD;
od_tuners.down_differential = MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
od_tuners.adj_up_threshold = MICRO_FREQUENCY_UP_THRESHOLD -
MICRO_FREQUENCY_DOWN_DIFFERENTIAL;
/*
* In nohz/micro accounting case we set the minimum frequency
* not depending on HZ, but fixed (very low). The deferred