fe8e288a63
Documentation for cpuidle infrastructure. (resend) Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Len Brown <len.brown@intel.com>
80 lines
2.7 KiB
Plaintext
80 lines
2.7 KiB
Plaintext
|
|
|
|
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
|
|
-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
|
|
-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
|
|
-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
|
|
-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)
|
|
* 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)
|