[RFC v4 1/5] PM: Add a sysfs file to represent the percentage of sleep in hardware state
From: Mario Limonciello
Date: Thu Nov 17 2022 - 17:59:05 EST
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 percentage of time spent in a sleep state.
This file will be present only if the system supports s2idle.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
RFC v3->v4
* Switch to a percentage for reporting
* Hook into timekeeping differently
---
Documentation/ABI/testing/sysfs-power | 9 +++++++
include/linux/suspend.h | 2 ++
include/linux/timekeeping.h | 1 +
kernel/power/main.c | 36 +++++++++++++++++++++++++++
kernel/time/timekeeping.c | 20 ++++++++++++---
5 files changed, 64 insertions(+), 4 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index f99d433ff311..60b6948f5982 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_percent
+Date: December 2022
+Contact: Mario Limonciello <mario.limonciello@xxxxxxx>
+Description:
+ The /sys/power/suspend_stats/last_hw_sleep_percent file
+ contains the percentage of time that the last suspend cycle
+ was spent in a hardware sleep state. It is expressed as an
+ integer between between 0 and 100.
+
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/include/linux/timekeeping.h b/include/linux/timekeeping.h
index fe1e467ba046..2a81366f3e31 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -70,6 +70,7 @@ extern ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs);
extern ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs);
extern ktime_t ktime_get_raw(void);
extern u32 ktime_get_resolution_ns(void);
+extern u64 get_suspend_duration_ns(void);
/**
* ktime_get_real - get the real (wall-) time in ktime_t format
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 31ec4a9b9d70..be82f4a740c0 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 +384,20 @@ 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_percent_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ u64 t = get_suspend_duration_ns();
+ int p;
+
+ if (!t)
+ return -EINVAL;
+
+ p = min((100 * NSEC_PER_USEC * suspend_stats.last_hw_sleep) / t, 100);
+ return sysfs_emit(buf, "%llu\n", p);
+}
+static struct kobj_attribute last_hw_sleep_percent = __ATTR_RO(last_hw_sleep_percent);
+
static struct attribute *suspend_attrs[] = {
&success.attr,
&fail.attr,
@@ -391,12 +412,27 @@ static struct attribute *suspend_attrs[] = {
&last_failed_dev.attr,
&last_failed_errno.attr,
&last_failed_step.attr,
+ &last_hw_sleep_percent.attr,
NULL,
};
+static umode_t suspend_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
+{
+ if (attr == &last_hw_sleep_percent.attr) {
+#ifdef CONFIG_ACPI
+ if (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0)
+ return 0444;
+#endif
+ return 0;
+ }
+
+ return 0444;
+}
+
static const struct attribute_group suspend_attr_group = {
.name = "suspend_stats",
.attrs = suspend_attrs,
+ .is_visible = suspend_attr_is_visible,
};
#ifdef CONFIG_DEBUG_FS
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index f72b9f1de178..49119a942cb2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1779,7 +1779,7 @@ void timekeeping_resume(void)
struct timekeeper *tk = &tk_core.timekeeper;
struct clocksource *clock = tk->tkr_mono.clock;
unsigned long flags;
- struct timespec64 ts_new, ts_delta;
+ struct timespec64 ts_new;
u64 cycle_now, nsec;
bool inject_sleeptime = false;
@@ -1806,16 +1806,16 @@ void timekeeping_resume(void)
cycle_now = tk_clock_read(&tk->tkr_mono);
nsec = clocksource_stop_suspend_timing(clock, cycle_now);
if (nsec > 0) {
- ts_delta = ns_to_timespec64(nsec);
+ timekeeping_suspend_time = ns_to_timespec64(nsec);
inject_sleeptime = true;
} else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
- ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
+ timekeeping_suspend_time = timespec64_sub(ts_new, timekeeping_suspend_time);
inject_sleeptime = true;
}
if (inject_sleeptime) {
suspend_timing_needed = false;
- __timekeeping_inject_sleeptime(tk, &ts_delta);
+ __timekeeping_inject_sleeptime(tk, &timekeeping_suspend_time);
}
/* Re-base the last cycle value */
@@ -2232,6 +2232,18 @@ void update_wall_time(void)
clock_was_set_delayed();
}
+/**
+ * get_suspend_duration_ns - Return the duration of a system suspend.
+ *
+ * Returns the calculation of the duration of time that passed while a
+ * system was suspended.
+ *
+ */
+u64 get_suspend_duration_ns(void)
+{
+ return timespec64_to_ns(&timekeeping_suspend_time);
+}
+
/**
* getboottime64 - Return the real time of system boot.
* @ts: pointer to the timespec64 to be set
--
2.34.1