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Documentation/cpuidle/sysfs.txt 3.37 KB
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fe8e288a6   Venkatesh Pallipadi   cpuidle: Add Docu... 
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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
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  -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
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  -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
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  -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
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  -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
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  -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
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  -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
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  -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
fe8e288a6   Venkatesh Pallipadi   cpuidle: Add Docu... 
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  -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)
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  * disable : Option to disable this idle state (bool) -> see note below
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  * 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)
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  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.