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Date: Tue, 20 Mar 2018 11:53:34 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] PM: cpuidle/suspend: Add s2idle usage and time state attributes
On Wednesday, March 14, 2018 12:27:21 PM CET Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> Add a new attribute group called "s2idle" under the sysfs directory
> of each cpuidle state that supports the ->enter_s2idle callback
> and put two new attributes, "usage" and "time", into that group to
> represent the number of times the given state was requested for
> suspend-to-idle and the total time spent in suspend-to-idle after
> requesting that state, respectively.
>
> That will allow diagnostic information related to suspend-to-idle
> to be collected without enabling advanced debug features and
> analyzing dmesg output.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Assuming to objections or concerns and queuing up.
> ---
> Documentation/ABI/testing/sysfs-devices-system-cpu | 25 +++++++++
> drivers/cpuidle/cpuidle.c | 9 +++
> drivers/cpuidle/sysfs.c | 54 +++++++++++++++++++++
> include/linux/cpuidle.h | 4 +
> 4 files changed, 92 insertions(+)
>
> Index: linux-pm/drivers/cpuidle/sysfs.c
> ===================================================================
> --- linux-pm.orig/drivers/cpuidle/sysfs.c
> +++ linux-pm/drivers/cpuidle/sysfs.c
> @@ -330,6 +330,58 @@ struct cpuidle_state_kobj {
> struct kobject kobj;
> };
>
> +#ifdef CONFIG_SUSPEND
> +#define define_show_state_s2idle_ull_function(_name) \
> +static ssize_t show_state_s2idle_##_name(struct cpuidle_state *state, \
> + struct cpuidle_state_usage *state_usage, \
> + char *buf) \
> +{ \
> + return sprintf(buf, "%llu\n", state_usage->s2idle_##_name);\
> +}
> +
> +define_show_state_s2idle_ull_function(usage);
> +define_show_state_s2idle_ull_function(time);
> +
> +#define define_one_state_s2idle_ro(_name, show) \
> +static struct cpuidle_state_attr attr_s2idle_##_name = \
> + __ATTR(_name, 0444, show, NULL)
> +
> +define_one_state_s2idle_ro(usage, show_state_s2idle_usage);
> +define_one_state_s2idle_ro(time, show_state_s2idle_time);
> +
> +static struct attribute *cpuidle_state_s2idle_attrs[] = {
> + &attr_s2idle_usage.attr,
> + &attr_s2idle_time.attr,
> + NULL
> +};
> +
> +static const struct attribute_group cpuidle_state_s2idle_group = {
> + .name = "s2idle",
> + .attrs = cpuidle_state_s2idle_attrs,
> +};
> +
> +static void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
> +{
> + int ret;
> +
> + if (!kobj->state->enter_s2idle)
> + return;
> +
> + ret = sysfs_create_group(&kobj->kobj, &cpuidle_state_s2idle_group);
> + if (ret)
> + pr_debug("%s: sysfs attribute group not created\n", __func__);
> +}
> +
> +static void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj)
> +{
> + if (kobj->state->enter_s2idle)
> + sysfs_remove_group(&kobj->kobj, &cpuidle_state_s2idle_group);
> +}
> +#else
> +static inline void cpuidle_add_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
> +static inline void cpuidle_remove_s2idle_attr_group(struct cpuidle_state_kobj *kobj) { }
> +#endif /* CONFIG_SUSPEND */
> +
> #define kobj_to_state_obj(k) container_of(k, struct cpuidle_state_kobj, kobj)
> #define kobj_to_state(k) (kobj_to_state_obj(k)->state)
> #define kobj_to_state_usage(k) (kobj_to_state_obj(k)->state_usage)
> @@ -383,6 +435,7 @@ static struct kobj_type ktype_state_cpui
>
> static inline void cpuidle_free_state_kobj(struct cpuidle_device *device, int i)
> {
> + cpuidle_remove_s2idle_attr_group(device->kobjs[i]);
> kobject_put(&device->kobjs[i]->kobj);
> wait_for_completion(&device->kobjs[i]->kobj_unregister);
> kfree(device->kobjs[i]);
> @@ -417,6 +470,7 @@ static int cpuidle_add_state_sysfs(struc
> kfree(kobj);
> goto error_state;
> }
> + cpuidle_add_s2idle_attr_group(kobj);
> kobject_uevent(&kobj->kobj, KOBJ_ADD);
> device->kobjs[i] = kobj;
> }
> Index: linux-pm/include/linux/cpuidle.h
> ===================================================================
> --- linux-pm.orig/include/linux/cpuidle.h
> +++ linux-pm/include/linux/cpuidle.h
> @@ -33,6 +33,10 @@ struct cpuidle_state_usage {
> unsigned long long disable;
> unsigned long long usage;
> unsigned long long time; /* in US */
> +#ifdef CONFIG_SUSPEND
> + unsigned long long s2idle_usage;
> + unsigned long long s2idle_time; /* in US */
> +#endif
> };
>
> struct cpuidle_state {
> Index: linux-pm/drivers/cpuidle/cpuidle.c
> ===================================================================
> --- linux-pm.orig/drivers/cpuidle/cpuidle.c
> +++ linux-pm/drivers/cpuidle/cpuidle.c
> @@ -131,6 +131,10 @@ int cpuidle_find_deepest_state(struct cp
> static void enter_s2idle_proper(struct cpuidle_driver *drv,
> struct cpuidle_device *dev, int index)
> {
> + ktime_t time_start, time_end;
> +
> + time_start = ns_to_ktime(local_clock());
> +
> /*
> * trace_suspend_resume() called by tick_freeze() for the last CPU
> * executing it contains RCU usage regarded as invalid in the idle
> @@ -152,6 +156,11 @@ static void enter_s2idle_proper(struct c
> */
> RCU_NONIDLE(tick_unfreeze());
> start_critical_timings();
> +
> + time_end = ns_to_ktime(local_clock());
> +
> + dev->states_usage[index].s2idle_time += ktime_us_delta(time_end, time_start);
> + dev->states_usage[index].s2idle_usage++;
> }
>
> /**
> Index: linux-pm/Documentation/ABI/testing/sysfs-devices-system-cpu
> ===================================================================
> --- linux-pm.orig/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ linux-pm/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -198,6 +198,31 @@ Description:
> time (in microseconds) this cpu should spend in this idle state
> to make the transition worth the effort.
>
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/
> +Date: March 2018
> +KernelVersion: v4.17
> +Contact: Linux power management list <linux-pm@...r.kernel.org>
> +Description:
> + Idle state usage statistics related to suspend-to-idle.
> +
> + This attribute group is only present for states that can be
> + used in suspend-to-idle with suspended timekeeping.
> +
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/time
> +Date: March 2018
> +KernelVersion: v4.17
> +Contact: Linux power management list <linux-pm@...r.kernel.org>
> +Description:
> + Total time spent by the CPU in suspend-to-idle (with scheduler
> + tick suspended) after requesting this state.
> +
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/usage
> +Date: March 2018
> +KernelVersion: v4.17
> +Contact: Linux power management list <linux-pm@...r.kernel.org>
> +Description:
> + Total number of times this state has been requested by the CPU
> + while entering suspend-to-idle.
>
> What: /sys/devices/system/cpu/cpu#/cpufreq/*
> Date: pre-git history
>
>
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