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Subject[PATCH] PM: cpuidle/suspend: Add s2idle usage and time state attributes
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Add a new attribute group called "s2idle" under the sysfs directory
of each cpuidle state that supports the ->enter_s2idle callback
and put two new attributes, "usage" and "time", into that group to
represent the number of times the given state was requested for
suspend-to-idle and the total time spent in suspend-to-idle after
requesting that state, respectively.

That will allow diagnostic information related to suspend-to-idle
to be collected without enabling advanced debug features and
analyzing dmesg output.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
Documentation/ABI/testing/sysfs-devices-system-cpu | 25 +++++++++
drivers/cpuidle/cpuidle.c | 9 +++
drivers/cpuidle/sysfs.c | 54 +++++++++++++++++++++
include/linux/cpuidle.h | 4 +
4 files changed, 92 insertions(+)

Index: linux-pm/drivers/cpuidle/sysfs.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/sysfs.c
+++ linux-pm/drivers/cpuidle/sysfs.c
@@ -330,6 +330,58 @@ struct cpuidle_state_kobj {
struct kobject kobj;
};

+#ifdef CONFIG_SUSPEND
+#define define_show_state_s2idle_ull_function(_name) \
+static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
+ struct cpuidle_state_usage *state_usage, \
+ char *buf) \
+{ \
+ return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
+}
+
+define_show_state_s2idle_ull_function(usage);
+define_show_state_s2idle_ull_function(time);
+
+#define define_one_state_s2idle_ro(_name, show) \
+static struct cpuidle_state_attr attr_s2idle_##_name = \
+ __ATTR(_name, 0444, show, NULL)
+
+define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
+define_one_state_s2idle_ro(time, show_state_s2idle_time);
+
+static struct attribute *cpuidle_state_s2idle_attrs[] = {
+ &attr_s2idle_usage.attr,
+ &attr_s2idle_time.attr,
+ NULL
+};
+
+static const struct attribute_group cpuidle_state_s2idle_group = {
+ .name = "s2idle",
+ .attrs = cpuidle_state_s2idle_attrs,
+};
+
+static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
+{
+ int ret;
+
+ if (!kobj->state->enter_s2idle)
+ return;
+
+ ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group);
+ if (ret)
+ pr_debug("%s: sysfs attribute group not created\n", __func__);
+}
+
+static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
+{
+ if (kobj->state->enter_s2idle)
+ sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group);
+}
+#else
+static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
+static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
+#endif /* CONFIG_SUSPEND */
+
#define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
#define kobj_to_state(k) (kobj_to_state_obj(k)->state)
#define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
@@ -383,6 +435,7 @@ static struct kobj_type ktype_state_cpui

static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
{
+ cpuidle_remove_s2idle_attr_group(device->kobjs[i]);
kobject_put(&device->kobjs[i]->kobj);
wait_for_completion(&device->kobjs[i]->kobj_unregister);
kfree(device->kobjs[i]);
@@ -417,6 +470,7 @@ static int cpuidle_add_state_sysfs(struc
kfree(kobj);
goto error_state;
}
+ cpuidle_add_s2idle_attr_group(kobj);
kobject_uevent(&kobj->kobj, KOBJ_ADD);
device->kobjs[i] = kobj;
}
Index: linux-pm/include/linux/cpuidle.h
===================================================================
--- linux-pm.orig/include/linux/cpuidle.h
+++ linux-pm/include/linux/cpuidle.h
@@ -33,6 +33,10 @@ struct cpuidle_state_usage {
unsigned long long disable;
unsigned long long usage;
unsigned long long time; /* in US */
+#ifdef CONFIG_SUSPEND
+ unsigned long long s2idle_usage;
+ unsigned long long s2idle_time; /* in US */
+#endif
};

struct cpuidle_state {
Index: linux-pm/drivers/cpuidle/cpuidle.c
===================================================================
--- linux-pm.orig/drivers/cpuidle/cpuidle.c
+++ linux-pm/drivers/cpuidle/cpuidle.c
@@ -131,6 +131,10 @@ int cpuidle_find_deepest_state(struct cp
static void enter_s2idle_proper(struct cpuidle_driver *drv,
struct cpuidle_device *dev, int index)
{
+ ktime_t time_start, time_end;
+
+ time_start = ns_to_ktime(local_clock());
+
/*
* trace_suspend_resume() called by tick_freeze() for the last CPU
* executing it contains RCU usage regarded as invalid in the idle
@@ -152,6 +156,11 @@ static void enter_s2idle_proper(struct c
*/
RCU_NONIDLE(tick_unfreeze());
start_critical_timings();
+
+ time_end = ns_to_ktime(local_clock());
+
+ dev->states_usage[index].s2idle_time += ktime_us_delta(time_end, time_start);
+ dev->states_usage[index].s2idle_usage++;
}

/**
Index: linux-pm/Documentation/ABI/testing/sysfs-devices-system-cpu
===================================================================
--- linux-pm.orig/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ linux-pm/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -198,6 +198,31 @@ Description:
time (in microseconds) this cpu should spend in this idle state
to make the transition worth the effort.

+What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/
+Date: March 2018
+KernelVersion: v4.17
+Contact: Linux power management list <linux-pm@vger.kernel.org>
+Description:
+ Idle state usage statistics related to suspend-to-idle.
+
+ This attribute group is only present for states that can be
+ used in suspend-to-idle with suspended timekeeping.
+
+What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/time
+Date: March 2018
+KernelVersion: v4.17
+Contact: Linux power management list <linux-pm@vger.kernel.org>
+Description:
+ Total time spent by the CPU in suspend-to-idle (with scheduler
+ tick suspended) after requesting this state.
+
+What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/usage
+Date: March 2018
+KernelVersion: v4.17
+Contact: Linux power management list <linux-pm@vger.kernel.org>
+Description:
+ Total number of times this state has been requested by the CPU
+ while entering suspend-to-idle.

What: /sys/devices/system/cpu/cpu#/cpufreq/*
Date: pre-git history
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