diff mbox

cpufreq: stats: clear statistics

Message ID 20161103204615.85395-1-code@mmayer.net (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Markus Mayer Nov. 3, 2016, 8:46 p.m. UTC 
From: Markus Mayer <mmayer@broadcom.com>

Allow cpufreq statistics to be cleared by writing anything to
/sys/.../cpufreq/stats/reset. Reading this new sysfs entry returns
nothing.

Resetting the statistics can be useful in a test environment (test
governor, retrieve stats, reset stats, test other governor, etc.). This
feature is not meant for production use.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
---
 drivers/cpufreq/Kconfig         | 10 ++++++++++
 drivers/cpufreq/cpufreq_stats.c | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

Comments

Rafael J. Wysocki Nov. 4, 2016, 12:28 a.m. UTC | #1 
On Thu, Nov 3, 2016 at 9:46 PM, Markus Mayer <code@mmayer.net> wrote:
> From: Markus Mayer <mmayer@broadcom.com>
>
> Allow cpufreq statistics to be cleared by writing anything to
> /sys/.../cpufreq/stats/reset. Reading this new sysfs entry returns
> nothing.
>
> Resetting the statistics can be useful in a test environment (test
> governor, retrieve stats, reset stats, test other governor, etc.). This
> feature is not meant for production use.
>
> Signed-off-by: Markus Mayer <mmayer@broadcom.com>
> ---
>  drivers/cpufreq/Kconfig         | 10 ++++++++++
>  drivers/cpufreq/cpufreq_stats.c | 32 ++++++++++++++++++++++++++++++++
>  2 files changed, 42 insertions(+)
>
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index d8b164a..97a458e 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -45,6 +45,16 @@ config CPU_FREQ_STAT_DETAILS
>
>           If in doubt, say N.
>
> +config CPU_FREQ_STAT_RESET
> +       bool "Allow reset of CPU frequency transition statistics"
> +       depends on CPU_FREQ_STAT
> +       help
> +         If enabled, writing to /sys/[...]/cpufreq/stats/reset will reset the
> +         current CPUfreq statistics. This is primarily meant for testing. It
> +         should not be enabled on a production system.
> +
> +         If in doubt, say N.
> +
>  choice
>         prompt "Default CPUFreq governor"
>         default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
> diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
> index 06d3abd..e4e1e3e 100644
> --- a/drivers/cpufreq/cpufreq_stats.c
> +++ b/drivers/cpufreq/cpufreq_stats.c
> @@ -111,6 +111,35 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
>  cpufreq_freq_attr_ro(trans_table);
>  #endif
>
> +#ifdef CONFIG_CPU_FREQ_STAT_RESET
> +static void cpufreq_stats_clear_table(struct cpufreq_policy *policy)
> +{
> +       struct cpufreq_stats *stats = policy->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_reset(struct cpufreq_policy *policy, char *buf)
> +{
> +       buf[0] = '\0';
> +       return 0;
> +}
> +
> +static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
> +                          size_t count)
> +{
> +       cpufreq_stats_clear_table(policy);
> +       return count;
> +}
> +cpufreq_freq_attr_rw(reset);
> +#endif
> +
>  cpufreq_freq_attr_ro(total_trans);
>  cpufreq_freq_attr_ro(time_in_state);
>
> @@ -120,6 +149,9 @@ static struct attribute *default_attrs[] = {
>  #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
>         &trans_table.attr,
>  #endif
> +#ifdef CONFIG_CPU_FREQ_STAT_RESET
> +       &reset.attr,
> +#endif
>         NULL
>  };
>  static struct attribute_group stats_attr_group = {
> --

What would be wrong with adding this unconditionally?

Thanks,
Rafael
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Viresh Kumar Nov. 4, 2016, 2:12 a.m. UTC | #2 
On 04-11-16, 01:28, Rafael J. Wysocki wrote:
> On Thu, Nov 3, 2016 at 9:46 PM, Markus Mayer <code@mmayer.net> wrote:
> > From: Markus Mayer <mmayer@broadcom.com>
> >
> > Allow cpufreq statistics to be cleared by writing anything to
> > /sys/.../cpufreq/stats/reset. Reading this new sysfs entry returns
> > nothing.
> >
> > Resetting the statistics can be useful in a test environment (test
> > governor, retrieve stats, reset stats, test other governor, etc.). This
> > feature is not meant for production use.
> >
> > Signed-off-by: Markus Mayer <mmayer@broadcom.com>
> > ---
> >  drivers/cpufreq/Kconfig         | 10 ++++++++++
> >  drivers/cpufreq/cpufreq_stats.c | 32 ++++++++++++++++++++++++++++++++
> >  2 files changed, 42 insertions(+)
> >
> > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> > index d8b164a..97a458e 100644
> > --- a/drivers/cpufreq/Kconfig
> > +++ b/drivers/cpufreq/Kconfig
> > @@ -45,6 +45,16 @@ config CPU_FREQ_STAT_DETAILS
> >
> >           If in doubt, say N.
> >
> > +config CPU_FREQ_STAT_RESET
> > +       bool "Allow reset of CPU frequency transition statistics"
> > +       depends on CPU_FREQ_STAT
> > +       help
> > +         If enabled, writing to /sys/[...]/cpufreq/stats/reset will reset the
> > +         current CPUfreq statistics. This is primarily meant for testing. It
> > +         should not be enabled on a production system.
> > +
> > +         If in doubt, say N.
> > +
> >  choice
> >         prompt "Default CPUFreq governor"
> >         default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
> > diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
> > index 06d3abd..e4e1e3e 100644
> > --- a/drivers/cpufreq/cpufreq_stats.c
> > +++ b/drivers/cpufreq/cpufreq_stats.c
> > @@ -111,6 +111,35 @@ static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
> >  cpufreq_freq_attr_ro(trans_table);
> >  #endif
> >
> > +#ifdef CONFIG_CPU_FREQ_STAT_RESET
> > +static void cpufreq_stats_clear_table(struct cpufreq_policy *policy)
> > +{
> > +       struct cpufreq_stats *stats = policy->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_reset(struct cpufreq_policy *policy, char *buf)
> > +{
> > +       buf[0] = '\0';
> > +       return 0;
> > +}
> > +
> > +static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
> > +                          size_t count)
> > +{
> > +       cpufreq_stats_clear_table(policy);
> > +       return count;
> > +}
> > +cpufreq_freq_attr_rw(reset);
> > +#endif
> > +
> >  cpufreq_freq_attr_ro(total_trans);
> >  cpufreq_freq_attr_ro(time_in_state);
> >
> > @@ -120,6 +149,9 @@ static struct attribute *default_attrs[] = {
> >  #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
> >         &trans_table.attr,
> >  #endif
> > +#ifdef CONFIG_CPU_FREQ_STAT_RESET
> > +       &reset.attr,
> > +#endif
> >         NULL
> >  };
> >  static struct attribute_group stats_attr_group = {
> > --
> 
> What would be wrong with adding this unconditionally?

Absolutely and there is no need to have read permissions for the file. Just make
it write only.
diff mbox

Patch

diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index d8b164a..97a458e 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -45,6 +45,16 @@  config CPU_FREQ_STAT_DETAILS
 
 	  If in doubt, say N.
 
+config CPU_FREQ_STAT_RESET
+	bool "Allow reset of CPU frequency transition statistics"
+	depends on CPU_FREQ_STAT
+	help
+	  If enabled, writing to /sys/[...]/cpufreq/stats/reset will reset the
+	  current CPUfreq statistics. This is primarily meant for testing. It
+	  should not be enabled on a production system.
+
+	  If in doubt, say N.
+
 choice
 	prompt "Default CPUFreq governor"
 	default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 06d3abd..e4e1e3e 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -111,6 +111,35 @@  static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 cpufreq_freq_attr_ro(trans_table);
 #endif
 
+#ifdef CONFIG_CPU_FREQ_STAT_RESET
+static void cpufreq_stats_clear_table(struct cpufreq_policy *policy)
+{
+	struct cpufreq_stats *stats = policy->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_reset(struct cpufreq_policy *policy, char *buf)
+{
+	buf[0] = '\0';
+	return 0;
+}
+
+static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf,
+			   size_t count)
+{
+	cpufreq_stats_clear_table(policy);
+	return count;
+}
+cpufreq_freq_attr_rw(reset);
+#endif
+
 cpufreq_freq_attr_ro(total_trans);
 cpufreq_freq_attr_ro(time_in_state);
 
@@ -120,6 +149,9 @@  static struct attribute *default_attrs[] = {
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 	&trans_table.attr,
 #endif
+#ifdef CONFIG_CPU_FREQ_STAT_RESET
+	&reset.attr,
+#endif
 	NULL
 };
 static struct attribute_group stats_attr_group = {