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+
+
+ Supporting multiple CPU idle levels in kernel
+
+ cpuidle sysfs
+
+System global cpuidle related information and tunables are under
+/sys/devices/system/cpu/cpuidle
+
+The current interfaces in this directory has self-explanatory names:
+* current_driver
+* current_governor_ro
+
+With cpuidle_sysfs_switch boot option (meant for developer testing)
+following objects are visible instead.
+* current_driver
+* available_governors
+* current_governor
+In this case users can switch the governor at run time by writing
+to current_governor.
+
+
+Per logical CPU specific cpuidle information are under
+/sys/devices/system/cpu/cpuX/cpuidle
+for each online cpu X
+
+--------------------------------------------------------------------------------
+# ls -lR /sys/devices/system/cpu/cpu0/cpuidle/
+/sys/devices/system/cpu/cpu0/cpuidle/:
+total 0
+drwxr-xr-x 2 root root 0 Feb 8 10:42 state0
+drwxr-xr-x 2 root root 0 Feb 8 10:42 state1
+drwxr-xr-x 2 root root 0 Feb 8 10:42 state2
+drwxr-xr-x 2 root root 0 Feb 8 10:42 state3
+
+/sys/devices/system/cpu/cpu0/cpuidle/state0:
+total 0
+-r--r--r-- 1 root root 4096 Feb 8 10:42 desc
+-rw-r--r-- 1 root root 4096 Feb 8 10:42 disable
+-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
+-r--r--r-- 1 root root 4096 Feb 8 10:42 name
+-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 time
+-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
+
+/sys/devices/system/cpu/cpu0/cpuidle/state1:
+total 0
+-r--r--r-- 1 root root 4096 Feb 8 10:42 desc
+-rw-r--r-- 1 root root 4096 Feb 8 10:42 disable
+-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
+-r--r--r-- 1 root root 4096 Feb 8 10:42 name
+-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 time
+-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
+
+/sys/devices/system/cpu/cpu0/cpuidle/state2:
+total 0
+-r--r--r-- 1 root root 4096 Feb 8 10:42 desc
+-rw-r--r-- 1 root root 4096 Feb 8 10:42 disable
+-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
+-r--r--r-- 1 root root 4096 Feb 8 10:42 name
+-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 time
+-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
+
+/sys/devices/system/cpu/cpu0/cpuidle/state3:
+total 0
+-r--r--r-- 1 root root 4096 Feb 8 10:42 desc
+-rw-r--r-- 1 root root 4096 Feb 8 10:42 disable
+-r--r--r-- 1 root root 4096 Feb 8 10:42 latency
+-r--r--r-- 1 root root 4096 Feb 8 10:42 name
+-r--r--r-- 1 root root 4096 Feb 8 10:42 power
+-r--r--r-- 1 root root 4096 Feb 8 10:42 time
+-r--r--r-- 1 root root 4096 Feb 8 10:42 usage
+--------------------------------------------------------------------------------
+
+
+* desc : Small description about the idle state (string)
+* disable : Option to disable this idle state (bool) -> see note below
+* latency : Latency to exit out of this idle state (in microseconds)
+* name : Name of the idle state (string)
+* power : Power consumed while in this idle state (in milliwatts)
+* time : Total time spent in this idle state (in microseconds)
+* usage : Number of times this state was entered (count)
+
+Note:
+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.