

		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_ro
* current_governor_ro

With cpuidle_sysfs_switch boot option (meant for developer testing)
following objects are visible instead.
* available_drivers
* available_governors
* current_driver
* current_governor
In this case user can switch the driver, governor at run time by writing
onto current_driver and current_governor.


Per logical CPU specific cpuidle information are under
/sys/devices/system/cpu/cpuX/cpuidle
for each online cpu X

Under this percpu directory, there is a directory for each idle state supported
by the driver, which in turn has
* latency : Latency to exit out of this idle state (in microseconds)
* 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)


