[RFD PATCH 09/10] cpuidle: sysfs: Add per cpu idle state prediction statistics

From: Daniel Lezcano
Date: Wed Oct 22 2014 - 09:58:54 EST


Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
drivers/cpuidle/cpuidle.c | 8 +++
drivers/cpuidle/sysfs.c | 156 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/cpuidle.h | 7 ++-
3 files changed, 170 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index bf42e17..66231a40 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -139,6 +139,14 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
*/
dev->states_usage[entered_state].time += dev->last_residency;
dev->states_usage[entered_state].usage++;
+ if (diff < dev->last_residency)
+ atomic_inc(&dev->over_estimate);
+ else if (entered_state < (drv->state_count - 1) &&
+ dev->last_residency <
+ drv->states[entered_state + 1].target_residency)
+ atomic_inc(&dev->under_estimate);
+ else
+ atomic_inc(&dev->right_estimate);
} else {
dev->last_residency = 0;
}
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c
index 97c5903..f446bd0 100644
--- a/drivers/cpuidle/sysfs.c
+++ b/drivers/cpuidle/sysfs.c
@@ -439,6 +439,154 @@ static void cpuidle_remove_state_sysfs(struct cpuidle_device *device)
cpuidle_free_state_kobj(device, i);
}

+#define kobj_to_stats_kobj(k) container_of(k, struct cpuidle_stats_kobj, kobj)
+#define attr_to_stats_attr(a) container_of(a, struct cpuidle_stats_attr, attr)
+
+#define define_show_stats_function(_name) \
+ static ssize_t show_stats_##_name(struct cpuidle_device *dev, \
+ char *buf) \
+ { \
+ return sprintf(buf, "%d\n", atomic_read(&dev->_name)); \
+ }
+
+#define define_store_stats_function(_name) \
+ static ssize_t store_stats_##_name(struct cpuidle_device *dev, \
+ const char *buf, size_t size) \
+ { \
+ unsigned long long value; \
+ int err; \
+ if (!capable(CAP_SYS_ADMIN)) \
+ return -EPERM; \
+ err = kstrtoull(buf, 0, &value); \
+ if (err) \
+ return err; \
+ \
+ atomic_set(&dev->_name, value); \
+ return size; \
+ }
+
+#define define_one_stats_rw(_name, show, store) \
+ static struct cpuidle_stats_attr attr_stats_##_name = \
+ __ATTR(_name, 0644, show, store)
+
+struct cpuidle_stats_kobj {
+ struct cpuidle_device *dev;
+ struct completion kobj_unregister;
+ struct kobject kobj;
+};
+
+struct cpuidle_stats_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct cpuidle_device *, char *);
+ ssize_t (*store)(struct cpuidle_device *, const char *, size_t);
+};
+
+static void cpuidle_stats_sysfs_release(struct kobject *kobj)
+{
+ struct cpuidle_stats_kobj *stats_kobj = kobj_to_stats_kobj(kobj);
+ complete(&stats_kobj->kobj_unregister);
+}
+
+static ssize_t cpuidle_stats_show(struct kobject *kobj, struct attribute *attr,
+ char *buf)
+{
+ int ret = -EIO;
+ struct cpuidle_stats_kobj *stats_kobj = kobj_to_stats_kobj(kobj);
+ struct cpuidle_stats_attr *dattr = attr_to_stats_attr(attr);
+
+ if (dattr->show)
+ ret = dattr->show(stats_kobj->dev, buf);
+
+ return ret;
+}
+
+static ssize_t cpuidle_stats_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf, size_t size)
+{
+ int ret = -EIO;
+ struct cpuidle_stats_kobj *stats_kobj = kobj_to_stats_kobj(kobj);
+ struct cpuidle_stats_attr *dattr = attr_to_stats_attr(attr);
+
+ if (dattr->store)
+ ret = dattr->store(stats_kobj->dev, buf, size);
+
+ return ret;
+}
+
+define_show_stats_function(right_estimate);
+define_store_stats_function(right_estimate);
+
+define_show_stats_function(under_estimate);
+define_store_stats_function(under_estimate);
+
+define_show_stats_function(over_estimate);
+define_store_stats_function(over_estimate);
+
+define_one_stats_rw(right_estimate,
+ show_stats_right_estimate,
+ store_stats_right_estimate);
+
+define_one_stats_rw(under_estimate,
+ show_stats_under_estimate,
+ store_stats_under_estimate);
+
+define_one_stats_rw(over_estimate,
+ show_stats_over_estimate,
+ store_stats_over_estimate);
+
+static const struct sysfs_ops cpuidle_stats_sysfs_ops = {
+ .show = cpuidle_stats_show,
+ .store = cpuidle_stats_store,
+};
+
+static struct attribute *cpuidle_stats_default_attrs[] = {
+ &attr_stats_right_estimate.attr,
+ &attr_stats_under_estimate.attr,
+ &attr_stats_over_estimate.attr,
+ NULL
+};
+
+static struct kobj_type ktype_stats_cpuidle = {
+ .sysfs_ops = &cpuidle_stats_sysfs_ops,
+ .default_attrs = cpuidle_stats_default_attrs,
+ .release = cpuidle_stats_sysfs_release,
+};
+
+static int cpuidle_add_stats_sysfs(struct cpuidle_device *dev)
+{
+ struct cpuidle_stats_kobj *kstats;
+ struct cpuidle_device_kobj *kdev = dev->kobj_dev;
+ int ret;
+
+ kstats = kzalloc(sizeof(*kstats), GFP_KERNEL);
+ if (!kstats)
+ return -ENOMEM;
+
+ kstats->dev = dev;
+ init_completion(&kstats->kobj_unregister);
+
+ ret = kobject_init_and_add(&kstats->kobj, &ktype_stats_cpuidle,
+ &kdev->kobj, "stats");
+ if (ret) {
+ kfree(kstats);
+ return ret;
+ }
+
+ kobject_uevent(&kstats->kobj, KOBJ_ADD);
+ dev->kobj_stats = kstats;
+
+ return ret;
+}
+
+static void cpuidle_remove_stats_sysfs(struct cpuidle_device *dev)
+{
+ struct cpuidle_stats_kobj *kstats = dev->kobj_stats;
+ kobject_put(&kstats->kobj);
+ wait_for_completion(&kstats->kobj_unregister);
+ kfree(kstats);
+}
+
#ifdef CONFIG_CPU_IDLE_MULTIPLE_DRIVERS
#define kobj_to_driver_kobj(k) container_of(k, struct cpuidle_driver_kobj, kobj)
#define attr_to_driver_attr(a) container_of(a, struct cpuidle_driver_attr, attr)
@@ -589,6 +737,13 @@ int cpuidle_add_device_sysfs(struct cpuidle_device *device)
ret = cpuidle_add_driver_sysfs(device);
if (ret)
cpuidle_remove_state_sysfs(device);
+
+ ret = cpuidle_add_stats_sysfs(device);
+ if (ret) {
+ cpuidle_remove_driver_sysfs(device);
+ cpuidle_remove_state_sysfs(device);
+ }
+
return ret;
}

@@ -598,6 +753,7 @@ int cpuidle_add_device_sysfs(struct cpuidle_device *device)
*/
void cpuidle_remove_device_sysfs(struct cpuidle_device *device)
{
+ cpuidle_remove_stats_sysfs(device);
cpuidle_remove_driver_sysfs(device);
cpuidle_remove_state_sysfs(device);
}
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index e99823f..c3b9bdd 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -44,7 +44,6 @@ struct cpuidle_state {
int power_usage; /* in mW */
unsigned int target_residency; /* in US */
bool disabled; /* disabled on all CPUs */
-
int (*enter) (struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index);
@@ -62,6 +61,7 @@ struct cpuidle_state {
struct cpuidle_device_kobj;
struct cpuidle_state_kobj;
struct cpuidle_driver_kobj;
+struct cpuidle_stats_kobj;

struct cpuidle_device {
unsigned int registered:1;
@@ -74,8 +74,13 @@ struct cpuidle_device {
struct cpuidle_state_kobj *kobjs[CPUIDLE_STATE_MAX];
struct cpuidle_driver_kobj *kobj_driver;
struct cpuidle_device_kobj *kobj_dev;
+ struct cpuidle_stats_kobj *kobj_stats;
struct list_head device_list;

+ atomic_t right_estimate;
+ atomic_t under_estimate;
+ atomic_t over_estimate;
+
#ifdef CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED
int safe_state_index;
cpumask_t coupled_cpus;
--
1.9.1

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