CPU Idle

Zynq UltraScale plus MPSoC Power Management

Release Date
2022-07-26
  • CPU Power Management
    • CPU Idle
      • [*] CPU idle PM support
      • [*] Ladder governor (for periodic timer tick)
      • ARM CPU Idle Drivers
        • [*] Generic ARM/ARM64 CPU idle Driver
$ ls -lR /sys/devices/system/cpu/cpu0/cpuidle/
/sys/devices/system/cpu/cpu0/cpuidle/:
drwxr-xr-x    2 root     root             0 Nov 19 17:24 driver
drwxr-xr-x    2 root     root             0 Nov 19 17:24 state0
drwxr-xr-x    3 root     root             0 Nov 19 17:24 state1

 
/sys/devices/system/cpu/cpu0/cpuidle/state0:
-r--r--r--    1 root     root          4096 Nov 19 17:24 above
-r--r--r--    1 root     root          4096 Nov 19 17:24 below
-r--r--r--    1 root     root          4096 Nov 19 17:24 default_status
-r--r--r--    1 root     root          4096 Nov 19 17:24 desc
-rw-r--r--    1 root     root          4096 Nov 19 17:24 disable
-r--r--r--    1 root     root          4096 Nov 19 17:24 latency
-r--r--r--    1 root     root          4096 Nov 19 17:24 name
-r--r--r--    1 root     root          4096 Nov 19 17:24 power
-r--r--r--    1 root     root          4096 Nov 19 17:24 rejected
-r--r--r--    1 root     root          4096 Nov 19 17:24 residency
-r--r--r--    1 root     root          4096 Nov 19 17:24 time
-r--r--r--    1 root     root          4096 Nov 19 17:24 usage

 
/sys/devices/system/cpu/cpu0/cpuidle/state1:

-r--r--r--    1 root     root          4096 Nov 19 17:27 above
-r--r--r--    1 root     root          4096 Nov 19 17:27 below
-r--r--r--    1 root     root          4096 Nov 19 17:27 default_status
-r--r--r--    1 root     root          4096 Nov 19 17:27 desc
-rw-r--r--    1 root     root          4096 Nov 19 17:27 disable
-r--r--r--    1 root     root          4096 Nov 19 17:27 latency
-r--r--r--    1 root     root          4096 Nov 19 17:27 name
-r--r--r--    1 root     root          4096 Nov 19 17:27 power
-r--r--r--    1 root     root          4096 Nov 19 17:27 rejected
-r--r--r--    1 root     root          4096 Nov 19 17:27 residency
drwxr-xr-x    2 root     root             0 Nov 19 17:27 s2idle
-r--r--r--    1 root     root          4096 Nov 19 17:27 time
-r--r--r--    1 root     root          4096 Nov 19 17:27 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)
$ ls -lR /sys/devices/system/cpu/cpuidle/
/sys/devices/system/cpu/cpuidle/:
-r--r--r--    1 root     root          4096 Nov 19 17:25 available_governors
-r--r--r--    1 root     root          4096 Nov 19 17:25 current_driver
-rw-r--r--    1 root     root          4096 Nov 19 17:25 current_governor
-r--r--r--    1 root     root          4096 Nov 19 17:25 current_governor_ro