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?
Wouldn't it be useful to have another attribute printing the
accumulated total HW sleep time?
> 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".
> + 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;
> +}
> +
> static const struct attribute_group suspend_attr_group = {
> .name = "suspend_stats",
> .attrs = suspend_attrs,
> + .is_visible = suspend_attr_is_visible,
> };
>
> #ifdef CONFIG_DEBUG_FS
> --
