cpufreq: stats: New sysfs attribute for clearing statistics

Allow CPUfreq statistics to be cleared by writing anything to
/sys/.../cpufreq/stats/reset.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Markus Mayer 2016-11-07 10:02:23 -08:00 committed by Rafael J. Wysocki
parent 26f0dbc9ab
commit ee7930ee27
3 changed files with 32 additions and 0 deletions

View File

@ -44,11 +44,17 @@ the stats driver insertion.
total 0
drwxr-xr-x 2 root root 0 May 14 16:06 .
drwxr-xr-x 3 root root 0 May 14 15:58 ..
--w------- 1 root root 4096 May 14 16:06 reset
-r--r--r-- 1 root root 4096 May 14 16:06 time_in_state
-r--r--r-- 1 root root 4096 May 14 16:06 total_trans
-r--r--r-- 1 root root 4096 May 14 16:06 trans_table
--------------------------------------------------------------------------------
- reset
Write-only attribute that can be used to reset the stat counters. This can be
useful for evaluating system behaviour under different governors without the
need for a reboot.
- time_in_state
This gives the amount of time spent in each of the frequencies supported by
this CPU. The cat output will have "<frequency> <time>" pair in each line, which

View File

@ -41,6 +41,18 @@ static int cpufreq_stats_update(struct cpufreq_stats *stats)
return 0;
}
static void cpufreq_stats_clear_table(struct cpufreq_stats *stats)
{
unsigned int count = stats->max_state;
memset(stats->time_in_state, 0, count * sizeof(u64));
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
memset(stats->trans_table, 0, count * count * sizeof(int));
#endif
stats->last_time = get_jiffies_64();
stats->total_trans = 0;
}
static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
{
return sprintf(buf, "%d\n", policy->stats->total_trans);
@ -64,6 +76,14 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
return len;
}
static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
size_t count)
{
/* We don't care what is written to the attribute. */
cpufreq_stats_clear_table(policy->stats);
return count;
}
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
{
@ -113,10 +133,12 @@ cpufreq_freq_attr_ro(trans_table);
cpufreq_freq_attr_ro(total_trans);
cpufreq_freq_attr_ro(time_in_state);
cpufreq_freq_attr_wo(reset);
static struct attribute *default_attrs[] = {
&total_trans.attr,
&time_in_state.attr,
&reset.attr,
#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
&trans_table.attr,
#endif

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@ -234,6 +234,10 @@ __ATTR(_name, _perm, show_##_name, NULL)
static struct freq_attr _name = \
__ATTR(_name, 0644, show_##_name, store_##_name)
#define cpufreq_freq_attr_wo(_name) \
static struct freq_attr _name = \
__ATTR(_name, 0200, NULL, store_##_name)
struct global_attr {
struct attribute attr;
ssize_t (*show)(struct kobject *kobj,