cpufreq: stats: clear statistics

PATCH Superseded Markus Mayer 2 participants 6 messages Nov 4, 2016 – Nov 7, 2016

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Documentation CPU frequency scaling framework

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Markus Mayer

author

2016-11-04 16:55 UTC #0 lore raw

v2 cover cpufreq: stats: clear statistics

From: Markus Mayer <[email protected]>

This series lets the user clear the CPUfreq stats by writing to a new sysfs attribute.

Changes since v1:
- add new cpufreq_freq_attr_wr_perm() macro for write-only attributes (because this is a separate commit, this patch has turned into a series)
- remove the Kconfig option, compiling the code unconditionally
- remove show_reset()
- cpufreq_stats_clear_table() takes a struct cpufreq_stats * as argument rather than a struct cpufreq_policy *

For v1, see https://lkml.org/lkml/2016/11/3/581.

Markus Mayer (2):
cpufreq: add new attribute type cpufreq_freq_attr_wr_perm()
cpufreq: stats: clear statistics

 Documentation/cpu-freq/cpufreq-stats.txt |  6 ++++++
 drivers/cpufreq/cpufreq_stats.c          | 22 ++++++++++++++++++++++
 include/linux/cpufreq.h                  |  4 ++++
 3 files changed, 32 insertions(+)

Signature · 1 line

2.7.4

Markus Mayer

author

2016-11-04 16:56 UTC #1 lore raw

PATCH v2 1/2 cpufreq: add new attribute type cpufreq_freq_attr_wr_perm()

From: Markus Mayer <[email protected]>

With the new attribute type, it is possible to create write-only CPUfreq attributes.

Signed-off-by Markus Mayer <[email protected]>

---
 include/linux/cpufreq.h | 4 ++++
 1 file changed, 4 insertions(+)

include/linux/cpufreq.h +4 -0

index 5fa55fc..ed09930 100644
@@ -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_wr_perm(_name, _perm)	\
+static struct freq_attr _name =			\
+__ATTR(_name, _perm, NULL, store_##_name)
+
 struct global_attr {
 	struct attribute attr;
 	ssize_t (*show)(struct kobject *kobj,

Signature · 1 line

2.7.4

Viresh Kumar

maintainer

2016-11-07 04:41 UTC #2 lore raw

Re: [PATCH v2 1/2] cpufreq: add new attribute type cpufreq_freq_attr_wr_perm()

Quoted 15 lines · Markus Mayer

From: Markus Mayer <[email protected]>
With the new attribute type, it is possible to create write-only CPUfreq attributes.
Signed-off-by Markus Mayer <[email protected]>
---
 include/linux/cpufreq.h | 4 ++++
 1 file changed, 4 insertions(+)
include/linux/cpufreq.h +0 -0
index 5fa55fc..ed09930 100644

include/linux/cpufreq.h __ATTR(_name, _perm, show_##_name, NULL) · line 237

Quoted 4 lines

include/linux/cpufreq.h +1 -0

@@ -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_wr_perm(_name, _perm)	\

shouldn't this be _wo_perm ?

Also, I wouldn't mind doing this in the second patch itself.

Quoted 8 lines

include/linux/cpufreq.h +3 -0

+static struct freq_attr _name =			\
+__ATTR(_name, _perm, NULL, store_##_name)
+
 struct global_attr {
 	struct attribute attr;
 	ssize_t (*show)(struct kobject *kobj,

Signature · 1 line

2.7.4

Signature · 1 line

viresh

Viresh Kumar

maintainer

2016-11-07 04:35 UTC #3 lore raw

Re: [PATCH v2 1/2] cpufreq: add new attribute type cpufreq_freq_attr_wr_perm()

Quoted 19 lines · Viresh Kumar

Quoted 18 lines · Markus Mayer
From: Markus Mayer <[email protected]>
With the new attribute type, it is possible to create write-only CPUfreq attributes.
Signed-off-by Markus Mayer <[email protected]>
---
 include/linux/cpufreq.h | 4 ++++
 1 file changed, 4 insertions(+)
include/linux/cpufreq.h +0 -0
index 5fa55fc..ed09930 100644
@@ -234,6 +234,10 @@ __ATTR(_name, _perm, show_##_name, NULL)
 static struct freq_attr _name =			\
 __ATTR(_name, 0644, show_##_name, store_##_name)
 

Quoted 5 lines

include/linux/cpufreq.h __ATTR(_name, _perm, show_##_name, NULL) · line 237
Quoted 1 line
include/linux/cpufreq.h +1 -0
+#define cpufreq_freq_attr_wr_perm(_name, _perm)	\
shouldn't this be _wo_perm ?
Also, I wouldn't mind doing this in the second patch itself.

Also there is no need to define a _perm variant here, and then you can avoid sending 0200 as argument as well.

Signature · 1 line

viresh

Markus Mayer

author

2016-11-04 16:55 UTC #4 lore raw

PATCH v2 2/2 cpufreq: stats: clear statistics

In reply to Markus Mayer

From: Markus Mayer <[email protected]>

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

Signed-off-by Markus Mayer <[email protected]>

---
 Documentation/cpu-freq/cpufreq-stats.txt |  6 ++++++
 drivers/cpufreq/cpufreq_stats.c          | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

Documentation/cpu-freq/cpufreq-stats.txt +6 -0

index 8d9773f..3c355f6 100644
@@ -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

drivers/cpufreq/cpufreq_stats.c +22 -0

index 06d3abd..66419e6 100644
@@ -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_wr_perm(reset, 0200);
 
 static struct attribute *default_attrs[] = {
 	&total_trans.attr,
 	&time_in_state.attr,
+	&reset.attr,
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 	&trans_table.attr,
 #endif

Signature · 1 line

2.7.4

Viresh Kumar

maintainer

2016-11-07 04:38 UTC #5 lore raw

Quoted 72 lines · Markus Mayer

From: Markus Mayer <[email protected]>

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

Signed-off-by Markus Mayer <[email protected]>

---
 Documentation/cpu-freq/cpufreq-stats.txt |  6 ++++++
 drivers/cpufreq/cpufreq_stats.c          | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

Documentation/cpu-freq/cpufreq-stats.txt +6 -0

index 8d9773f..3c355f6 100644
@@ -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

drivers/cpufreq/cpufreq_stats.c +20 -0

index 06d3abd..66419e6 100644
@@ -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)
 {

drivers/cpufreq/cpufreq_stats.c cpufreq_freq_attr_ro(trans_table); · line 136

Quoted 4 lines

drivers/cpufreq/cpufreq_stats.c +1 -0

@@ -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_wr_perm(reset, 0200);

Just drop the perm argument and this patch looks fine as well.

Signature · 1 line

viresh