Commit b52124a7 authored by Mario Limonciello's avatar Mario Limonciello Committed by Rafael J. Wysocki
Browse files

PM: Add sysfs files to represent time spent in hardware sleep state 



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 3 new sysfs files:
1) The time spent in a hw sleep state for last cycle.
2) The time spent in a hw sleep state since the kernel booted
3) The maximum time that the hardware can report for a sleep cycle.
All of these files will be present only if the system supports s2idle.

Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 6a8f57ae

Documentation/ABI/testing/sysfs-power

+29 −0
Original line number Diff line number Diff line
@@ -413,6 +413,35 @@ 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 in the most recent system suspend-resume cycle.

		This number is measured in microseconds.



What:		/sys/power/suspend_stats/total_hw_sleep

Date:		June 2023

Contact:	Mario Limonciello <mario.limonciello@amd.com>

Description:

		The /sys/power/suspend_stats/total_hw_sleep file

		contains the aggregate of time spent in a hardware sleep

		state since the kernel was booted. This number

		is measured in microseconds.



What:		/sys/power/suspend_stats/max_hw_sleep

Date:		June 2023

Contact:	Mario Limonciello <mario.limonciello@amd.com>

Description:

		The /sys/power/suspend_stats/max_hw_sleep file

		contains the maximum amount of time that the hardware can

		report for time spent in a hardware sleep state. When sleep

		cycles are longer than this time, the values for

		'total_hw_sleep' and 'last_hw_sleep' may not be accurate.

		This number is measured in microseconds.



What:		/sys/power/sync_on_suspend

Date:		October 2019

Contact:	Jonas Meurer <jonas@freesources.org>

include/linux/suspend.h

+8 −0
Original line number Diff line number Diff line
@@ -68,6 +68,9 @@ struct suspend_stats { 
	int	last_failed_errno;

	int	errno[REC_FAILED_NUM];

	int	last_failed_step;

	u64	last_hw_sleep;

	u64	total_hw_sleep;

	u64	max_hw_sleep;

	enum suspend_stat_step	failed_steps[REC_FAILED_NUM];

};
@@ -489,6 +492,8 @@ 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_report_hw_sleep_time(u64 t);

extern void pm_report_max_hw_sleep(u64 t);



#define pm_notifier(fn, pri) {				\

	static struct notifier_block fn##_nb =			\
@@ -526,6 +531,9 @@ static inline int unregister_pm_notifier(struct notifier_block *nb) 
	return 0;

}



static inline void pm_report_hw_sleep_time(u64 t) {};

static inline void pm_report_max_hw_sleep(u64 t) {};



static inline void ksys_sync_helper(void) {}



#define pm_notifier(fn, pri)	do { (void)(fn); } while (0)

kernel/power/main.c

+47 −12
Original line number Diff line number Diff line
@@ -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 +84,19 @@ int unregister_pm_notifier(struct notifier_block *nb) 
}

EXPORT_SYMBOL_GPL(unregister_pm_notifier);



void pm_report_hw_sleep_time(u64 t)

{

	suspend_stats.last_hw_sleep = t;

	suspend_stats.total_hw_sleep += t;

}

EXPORT_SYMBOL_GPL(pm_report_hw_sleep_time);



void pm_report_max_hw_sleep(u64 t)

{

	suspend_stats.max_hw_sleep = t;

}

EXPORT_SYMBOL_GPL(pm_report_max_hw_sleep);



int pm_notifier_call_chain_robust(unsigned long val_up, unsigned long val_down)

{

	int ret;
@@ -314,24 +328,27 @@ static char *suspend_step_name(enum suspend_stat_step step) 
	}

}



#define suspend_attr(_name)					\

#define suspend_attr(_name, format_str)				\

static ssize_t _name##_show(struct kobject *kobj,		\

		struct kobj_attribute *attr, char *buf)		\

{								\

	return sprintf(buf, "%d\n", suspend_stats._name);	\

	return sprintf(buf, format_str, suspend_stats._name);	\

}								\

static struct kobj_attribute _name = __ATTR_RO(_name)



suspend_attr(success);

suspend_attr(fail);

suspend_attr(failed_freeze);

suspend_attr(failed_prepare);

suspend_attr(failed_suspend);

suspend_attr(failed_suspend_late);

suspend_attr(failed_suspend_noirq);

suspend_attr(failed_resume);

suspend_attr(failed_resume_early);

suspend_attr(failed_resume_noirq);

suspend_attr(success, "%d\n");

suspend_attr(fail, "%d\n");

suspend_attr(failed_freeze, "%d\n");

suspend_attr(failed_prepare, "%d\n");

suspend_attr(failed_suspend, "%d\n");

suspend_attr(failed_suspend_late, "%d\n");

suspend_attr(failed_suspend_noirq, "%d\n");

suspend_attr(failed_resume, "%d\n");

suspend_attr(failed_resume_early, "%d\n");

suspend_attr(failed_resume_noirq, "%d\n");

suspend_attr(last_hw_sleep, "%llu\n");

suspend_attr(total_hw_sleep, "%llu\n");

suspend_attr(max_hw_sleep, "%llu\n");



static ssize_t last_failed_dev_show(struct kobject *kobj,

		struct kobj_attribute *attr, char *buf)
@@ -391,12 +408,30 @@ static struct attribute *suspend_attrs[] = { 
	&last_failed_dev.attr,

	&last_failed_errno.attr,

	&last_failed_step.attr,

	&last_hw_sleep.attr,

	&total_hw_sleep.attr,

	&max_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 &&

	    attr != &total_hw_sleep.attr &&

	    attr != &max_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