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Message-ID: <460b23ee-16ed-f1e3-0e14-35051c908671@amd.com>
Date: Tue, 15 Nov 2022 09:17:34 -0600
From: "Limonciello, Mario" <mario.limonciello@....com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Sven van Ashbrook <svenva@...omium.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 11/15/2022 08:45, Rafael J. Wysocki wrote:
> 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
>
This has a dependency on the platform firmware offering an ACPI LPIT
table. I don't know how common that is. As this series started from
the needs on ChromeOS I would ask is that typically populated by coreboot?
I would hope it's the same number that is populated in that file on
supported systems though.
> and
>
> /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
>
No relation to this one for what's in the series.
>> 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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