On 3/31/2023 13:01, Rafael J. Wysocki wrote:
On Thu, Mar 30, 2023 at 9:45 PM Mario Limonciello
<mario.limonciello@xxxxxxx> wrote:
Userspace can't easily discover how much of a sleep cycle was spent in a
hardware sleep state without using kernel tracing and vendor specific sysfs
or debugfs files.
To make this information more discoverable, introduce a new sysfs file
to represent the time spent in a sleep state.
This is only in the most recent suspend-resume cycle, isn't it?
Yes; that's correct.
Wouldn't it be useful to have another attribute printing the
accumulated total HW sleep time?
I had considered this; but I didn't think it was actually very useful
because userspace will get control at the end of every cycle and can
accumulate those numbers if desirable.
This file will be present only if the system supports s2idle.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v4->v5:
* Provide time in microseconds instead of percent. Userspace can convert
this if desirable.
---
Documentation/ABI/testing/sysfs-power | 9 +++++++++
include/linux/suspend.h | 2 ++
kernel/power/main.c | 29 +++++++++++++++++++++++++++
3 files changed, 40 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index f99d433ff311..9e0c31b9ce85 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -413,6 +413,15 @@ Description:
The /sys/power/suspend_stats/last_failed_step file contains
the last failed step in the suspend/resume path.
+What: /sys/power/suspend_stats/last_hw_sleep
+Date: June 2023
+Contact: Mario Limonciello <mario.limonciello@xxxxxxx>
+Description:
+ The /sys/power/suspend_stats/last_hw_sleep file
+ contains the duration of time spent in a hardware sleep
+ state during from the previous suspend cycle. This number
"during from"?
I would say "in the most recent system suspend-resume cycle".
Ack, thanks.
+ is measured in microseconds.
+
What: /sys/power/sync_on_suspend
Date: October 2019
Contact: Jonas Meurer <jonas@xxxxxxxxxxxxxxx>
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index cfe19a028918..e0f2ac5f4406 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -68,6 +68,7 @@ struct suspend_stats {
int last_failed_errno;
int errno[REC_FAILED_NUM];
int last_failed_step;
+ u64 last_hw_sleep;
enum suspend_stat_step failed_steps[REC_FAILED_NUM];
};
@@ -489,6 +490,7 @@ void restore_processor_state(void);
extern int register_pm_notifier(struct notifier_block *nb);
extern int unregister_pm_notifier(struct notifier_block *nb);
extern void ksys_sync_helper(void);
+extern void pm_set_hw_sleep_time(u64 t);
#define pm_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 31ec4a9b9d70..6a2bf8784ce8 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -6,6 +6,7 @@
* Copyright (c) 2003 Open Source Development Lab
*/
+#include <linux/acpi.h>
#include <linux/export.h>
#include <linux/kobject.h>
#include <linux/string.h>
@@ -83,6 +84,12 @@ int unregister_pm_notifier(struct notifier_block *nb)
}
EXPORT_SYMBOL_GPL(unregister_pm_notifier);
+void pm_set_hw_sleep_time(u64 t)
+{
+ suspend_stats.last_hw_sleep = t;
+}
+EXPORT_SYMBOL_GPL(pm_set_hw_sleep_time);
+
int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)
{
int ret;
@@ -377,6 +384,13 @@ static ssize_t last_failed_step_show(struct kobject *kobj,
}
static struct kobj_attribute last_failed_step = __ATTR_RO(last_failed_step);
+static ssize_t last_hw_sleep_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ return sysfs_emit(buf, "%llu\n", suspend_stats.last_hw_sleep);
+}
+static struct kobj_attribute last_hw_sleep = __ATTR_RO(last_hw_sleep);
+
static struct attribute *suspend_attrs[] = {
&success.attr,
&fail.attr,
@@ -391,12 +405,27 @@ static struct attribute *suspend_attrs[] = {
&last_failed_dev.attr,
&last_failed_errno.attr,
&last_failed_step.attr,
+ &last_hw_sleep.attr,
NULL,
};
+static umode_t suspend_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
+{
+ if (attr == &last_hw_sleep.attr) {
+#ifdef CONFIG_ACPI
+ if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
+ return 0444;
+#endif
+ return 0;
+ }
+
+ return 0444;
if (attr != &last_hw_sleep.attr)
return 0444;
#ifdef CONFIG_ACPI
if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
return 0444;
#endif
return 0;
Ack, thanks.
+}
+
static const struct attribute_group suspend_attr_group = {
.name = "suspend_stats",
.attrs = suspend_attrs,
+ .is_visible = suspend_attr_is_visible,
};
#ifdef CONFIG_DEBUG_FS
--
