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Message-ID: <CAJZ5v0iwpSkd_8CS1dq6+rkszeKGygBbeifvugAEEKqA0w1s7w@mail.gmail.com>
Date: Tue, 15 Nov 2022 15:45:58 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>
Cc: Sven van Ashbrook <svenva@...omium.org>,
Rafael J Wysocki <rafael@...nel.org>,
linux-pm@...r.kernel.org, platform-driver-x86@...r.kernel.org,
Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
John Stultz <jstultz@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Stephen Boyd <sboyd@...nel.org>,
Rajneesh Bhardwaj <irenic.rajneesh@...il.com>,
S-k Shyam-sundar <Shyam-sundar.S-k@....com>,
rrangel@...omium.org, Rajat Jain <rajatja@...gle.com>,
David E Box <david.e.box@...el.com>,
Hans de Goede <hdegoede@...hat.com>,
linux-kernel@...r.kernel.org
Subject: Re: [RFC v2 1/3] PM: Add a sysfs files to represent sleep duration
On Thu, Nov 10, 2022 at 7:49 AM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> Both AMD and Intel SoCs have a concept of reporting whether the hardware
> reached a hardware sleep state over s2idle as well as how much
> time was spent in such a state.
>
> This information is valuable to both chip designers and system designers
> as it helps to identify when there are problems with power consumption
> over an s2idle cycle.
>
> To make the information discoverable, create a new sysfs file and a symbol
> that drivers from supported manufacturers can use to advertise this
> information. This file will only be exported when the system supports low
> power idle in the ACPI table.
>
> In order to effectively use this information you will ideally want to
> compare against the total duration of sleep, so export a second sysfs file
> that will show total time. This file will be exported on all systems and
> used both for s2idle and s3.
Well, my first question would be how this is related to
/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
and
/sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
> Suggested-by: David E Box <david.e.box@...el.com>
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> ---
> Documentation/ABI/testing/sysfs-power | 17 +++++++++++
> include/linux/suspend.h | 4 +++
> kernel/power/main.c | 42 +++++++++++++++++++++++++++
> kernel/power/suspend.c | 2 ++
> kernel/time/timekeeping.c | 2 ++
> 5 files changed, 67 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
> index f99d433ff311..5b47cbb4dc9e 100644
> --- a/Documentation/ABI/testing/sysfs-power
> +++ b/Documentation/ABI/testing/sysfs-power
> @@ -413,6 +413,23 @@ 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_state_residency
> +Date: December 2022
> +Contact: Mario Limonciello <mario.limonciello@....com>
> +Description:
> + The /sys/power/suspend_stats/last_hw_state_residency file contains
> + the amount of time spent in a hardware sleep state.
> + This attribute is only available if the system supports
> + low power idle. This is measured in microseconds.
> +
> +What: /sys/power/suspend_stats/last_suspend_total
> +Date: December 2022
> +Contact: Mario Limonciello <mario.limonciello@....com>
> +Description:
> + The /sys/power/suspend_stats/last_suspend_total file contains
> + the total duration of the sleep cycle.
> + This is measured in microseconds.
> +
> What: /sys/power/sync_on_suspend
> Date: October 2019
> Contact: Jonas Meurer <jonas@...esources.org>
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index cfe19a028918..af343c3f8198 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -68,6 +68,8 @@ struct suspend_stats {
> int last_failed_errno;
> int errno[REC_FAILED_NUM];
> int last_failed_step;
> + u64 last_hw_state_residency;
> + u64 last_suspend_total;
> enum suspend_stat_step failed_steps[REC_FAILED_NUM];
> };
>
> @@ -489,6 +491,8 @@ 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_set_hw_state_residency(u64 duration);
> +extern void pm_account_suspend_type(const struct timespec64 *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..11bd658583b0 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>
> @@ -54,6 +55,19 @@ void unlock_system_sleep(unsigned int flags)
> }
> EXPORT_SYMBOL_GPL(unlock_system_sleep);
>
> +void pm_set_hw_state_residency(u64 duration)
> +{
> + suspend_stats.last_hw_state_residency = duration;
> +}
> +EXPORT_SYMBOL_GPL(pm_set_hw_state_residency);
> +
> +void pm_account_suspend_type(const struct timespec64 *t)
> +{
> + suspend_stats.last_suspend_total += (s64)t->tv_sec * USEC_PER_SEC +
> + t->tv_nsec / NSEC_PER_USEC;
> +}
> +EXPORT_SYMBOL_GPL(pm_account_suspend_type);
> +
> void ksys_sync_helper(void)
> {
> ktime_t start;
> @@ -377,6 +391,20 @@ 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_state_residency_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "%llu\n", suspend_stats.last_hw_state_residency);
> +}
> +static struct kobj_attribute last_hw_state_residency = __ATTR_RO(last_hw_state_residency);
> +
> +static ssize_t last_suspend_total_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + return sprintf(buf, "%llu\n", suspend_stats.last_suspend_total);
> +}
> +static struct kobj_attribute last_suspend_total = __ATTR_RO(last_suspend_total);
> +
> static struct attribute *suspend_attrs[] = {
> &success.attr,
> &fail.attr,
> @@ -391,12 +419,26 @@ static struct attribute *suspend_attrs[] = {
> &last_failed_dev.attr,
> &last_failed_errno.attr,
> &last_failed_step.attr,
> + &last_hw_state_residency.attr,
> + &last_suspend_total.attr,
> NULL,
> };
>
> +static umode_t suspend_attr_is_visible(struct kobject *kobj, struct attribute *attr, int idx)
> +{
> + if (attr != &last_hw_state_residency.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
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index fa3bf161d13f..b6c4a3733212 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -423,6 +423,8 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
> if (suspend_test(TEST_PLATFORM))
> goto Platform_wake;
>
> + suspend_stats.last_suspend_total = 0;
> +
> if (state == PM_SUSPEND_TO_IDLE) {
> s2idle_loop();
> goto Platform_wake;
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index f72b9f1de178..e1b356787e53 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -24,6 +24,7 @@
> #include <linux/compiler.h>
> #include <linux/audit.h>
> #include <linux/random.h>
> +#include <linux/suspend.h>
>
> #include "tick-internal.h"
> #include "ntp_internal.h"
> @@ -1698,6 +1699,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
> tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
> tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
> tk_debug_account_sleep_time(delta);
> + pm_account_suspend_type(delta);
> }
>
> #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
> --
> 2.34.1
>
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