Messages in this thread | | | Date | Fri, 31 Mar 2023 13:05:09 -0500 | Subject | Re: [PATCH v5 1/4] PM: Add a sysfs file to represent time spent in hardware sleep state | From | "Limonciello, Mario" <> |
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On 3/31/2023 13:01, Rafael J. Wysocki wrote: > On Thu, Mar 30, 2023 at 9:45 PM Mario Limonciello > <mario.limonciello@amd.com> 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@amd.com> >> --- >> 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@amd.com> >> +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@freesources.org> >> 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 >> --
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