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SubjectRe: [PATCH v4] Documentation/ABI: update cpuidle sysfs documentation
On Tue, Feb 6, 2018 at 8:19 PM, Aishwarya Pant <aishpant@gmail.com> wrote:
> Update cpuidle documentation using git logs and existing documentation
> in Documentation/cpuidle/sysfs.txt. This might be useful for scripting
> and tracking changes in the ABI.
>
> Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
> ---
> Changes in v4:
> - Fix patch formatting
> v3:
> - Fix subject line
> v2:
> - Merge cpuidle_sysfs_switch attributes' description with the previous
> entry.
>
> Documentation/ABI/testing/sysfs-devices-system-cpu | 77 +++++++++++++++++++++-
> 1 file changed, 75 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index bfd29bc8d37a..e9ee67f80933 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -108,6 +108,8 @@ Description: CPU topology files that describe a logical CPU's relationship
>
> What: /sys/devices/system/cpu/cpuidle/current_driver
> /sys/devices/system/cpu/cpuidle/current_governer_ro
> + /sys/devices/system/cpu/cpuidle/available_governors
> + /sys/devices/system/cpu/cpuidle/current_governor
> Date: September 2007
> Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
> Description: Discover cpuidle policy and mechanism
> @@ -119,13 +121,84 @@ Description: Discover cpuidle policy and mechanism
> Idle policy (governor) is differentiated from idle mechanism
> (driver)
>
> - current_driver: displays current idle mechanism
> + current_driver: (RO) displays current idle mechanism
>
> - current_governor_ro: displays current idle policy
> + current_governor_ro: (RO) displays current idle policy
> +
> + With the cpuidle_sysfs_switch boot option enabled (meant for
> + developer testing), the following three attributes are visible
> + instead:
> +
> + current_driver: same as described above
> +
> + available_governors: (RO) displays a space separated list of
> + available governors
> +
> + current_governor: (RW) displays current idle policy. Users can
> + switch the governor at runtime by writing to this file.
>
> See files in Documentation/cpuidle/ for more information.
>
>
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/name
> + /sys/devices/system/cpu/cpuX/cpuidle/stateN/latency
> + /sys/devices/system/cpu/cpuX/cpuidle/stateN/power
> + /sys/devices/system/cpu/cpuX/cpuidle/stateN/time
> + /sys/devices/system/cpu/cpuX/cpuidle/stateN/usage
> +Date: September 2007
> +KernelVersion: v2.6.24
> +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>

Please replace "Linux kernel mailing list
<linux-kernel@vger.kernel.org>" with "Linux power management list
<linux-pm@vger.kernel.org>" here and below.

> +Description:
> + The directory /sys/devices/system/cpu/cpuX/cpuidle contains per
> + logical CPU specific cpuidle information for each online cpu X.
> + The processor idle states which are available for use have the
> + following attributes:
> +
> + name: (RO) Name of the idle state (string).
> +
> + latency: (RO) The latency to exit out of this idle state (in
> + microseconds).
> +
> + power: (RO) The power consumed while in this idle state (in
> + milliwatts).
> +
> + time: (RO) The total time spent in this idle state (in microseconds).
> +
> + usage: (RO) Number of times this state was entered (a count).
> +
> +
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/desc
> +Date: February 2008
> +KernelVersion: v2.6.25
> +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
> +Description:
> + (RO) A small description about the idle state (string).
> +
> +
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/disable
> +Date: March 2012
> +KernelVersion: v3.10
> +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
> +Description:
> + (RW) Option to disable this idle state (bool). The behavior and
> + the effect of the disable variable depends on the implementation
> + of a particular governor. In the ladder governor, for example,
> + it is not coherent, i.e. if one is disabling a light state, then
> + all deeper states are disabled as well, but the disable variable
> + does not reflect it. Likewise, if one enables a deep state but a
> + lighter state still is disabled, then this has no effect.
> +
> +
> +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/residency
> +Date: March 2014
> +KernelVersion: v3.15
> +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
> +Description:
> + (RO) Display the target residency i.e. the minimum amount of
> + time (in microseconds) this cpu should spend in this idle state
> + to make the transition worth the effort.
> +
> +
> What: /sys/devices/system/cpu/cpu#/cpufreq/*
> Date: pre-git history
> Contact: linux-pm@vger.kernel.org
> --
> 2.16.1
>

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