1
2
3		Supporting multiple CPU idle levels in kernel
4
5				cpuidle sysfs
6
7System global cpuidle related information and tunables are under
8/sys/devices/system/cpu/cpuidle
9
10The current interfaces in this directory has self-explanatory names:
11* current_driver
12* current_governor_ro
13
14With cpuidle_sysfs_switch boot option (meant for developer testing)
15following objects are visible instead.
16* current_driver
17* available_governors
18* current_governor
19In this case users can switch the governor at run time by writing
20to current_governor.
21
22
23Per logical CPU specific cpuidle information are under
24/sys/devices/system/cpu/cpuX/cpuidle
25for each online cpu X
26
27--------------------------------------------------------------------------------
28# ls -lR /sys/devices/system/cpu/cpu0/cpuidle/
29/sys/devices/system/cpu/cpu0/cpuidle/:
30total 0
31drwxr-xr-x 2 root root 0 Feb  8 10:42 state0
32drwxr-xr-x 2 root root 0 Feb  8 10:42 state1
33drwxr-xr-x 2 root root 0 Feb  8 10:42 state2
34drwxr-xr-x 2 root root 0 Feb  8 10:42 state3
35
36/sys/devices/system/cpu/cpu0/cpuidle/state0:
37total 0
38-r--r--r-- 1 root root 4096 Feb  8 10:42 desc
39-r--r--r-- 1 root root 4096 Feb  8 10:42 latency
40-r--r--r-- 1 root root 4096 Feb  8 10:42 name
41-r--r--r-- 1 root root 4096 Feb  8 10:42 power
42-r--r--r-- 1 root root 4096 Feb  8 10:42 time
43-r--r--r-- 1 root root 4096 Feb  8 10:42 usage
44
45/sys/devices/system/cpu/cpu0/cpuidle/state1:
46total 0
47-r--r--r-- 1 root root 4096 Feb  8 10:42 desc
48-r--r--r-- 1 root root 4096 Feb  8 10:42 latency
49-r--r--r-- 1 root root 4096 Feb  8 10:42 name
50-r--r--r-- 1 root root 4096 Feb  8 10:42 power
51-r--r--r-- 1 root root 4096 Feb  8 10:42 time
52-r--r--r-- 1 root root 4096 Feb  8 10:42 usage
53
54/sys/devices/system/cpu/cpu0/cpuidle/state2:
55total 0
56-r--r--r-- 1 root root 4096 Feb  8 10:42 desc
57-r--r--r-- 1 root root 4096 Feb  8 10:42 latency
58-r--r--r-- 1 root root 4096 Feb  8 10:42 name
59-r--r--r-- 1 root root 4096 Feb  8 10:42 power
60-r--r--r-- 1 root root 4096 Feb  8 10:42 time
61-r--r--r-- 1 root root 4096 Feb  8 10:42 usage
62
63/sys/devices/system/cpu/cpu0/cpuidle/state3:
64total 0
65-r--r--r-- 1 root root 4096 Feb  8 10:42 desc
66-r--r--r-- 1 root root 4096 Feb  8 10:42 latency
67-r--r--r-- 1 root root 4096 Feb  8 10:42 name
68-r--r--r-- 1 root root 4096 Feb  8 10:42 power
69-r--r--r-- 1 root root 4096 Feb  8 10:42 time
70-r--r--r-- 1 root root 4096 Feb  8 10:42 usage
71--------------------------------------------------------------------------------
72
73
74* desc : Small description about the idle state (string)
75* latency : Latency to exit out of this idle state (in microseconds)
76* name : Name of the idle state (string)
77* power : Power consumed while in this idle state (in milliwatts)
78* time : Total time spent in this idle state (in microseconds)
79* usage : Number of times this state was entered (count)
80