Documentation/ABI: update cpuidle sysfs documentation
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>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index bfd29bc..4ed63b6 100644
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -108,6 +108,8 @@
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 @@
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 power management list <linux-pm@vger.kernel.org>
+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 power management list <linux-pm@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 power management list <linux-pm@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 power management list <linux-pm@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