TEXT   74

sysfs

Guest on 3rd June 2022 01:51:29 AM

  1.  
  2.  
  3.                 Supporting multiple CPU idle levels in kernel
  4.  
  5.                                 cpuidle sysfs
  6.  
  7. System global cpuidle related information and tunables are under
  8. /sys/devices/system/cpu/cpuidle
  9.  
  10. The current interfaces in this directory has self-explanatory names:
  11. * current_driver
  12. * current_governor_ro
  13.  
  14. With cpuidle_sysfs_switch boot option (meant for developer testing)
  15. following objects are visible instead.
  16. * current_driver
  17. * available_governors
  18. * current_governor
  19. In this case users can switch the governor at run time by writing
  20. to current_governor.
  21.  
  22.  
  23. Per logical CPU specific cpuidle information are under
  24. /sys/devices/system/cpu/cpuX/cpuidle
  25. for each online cpu X
  26.  
  27. --------------------------------------------------------------------------------
  28. # ls -lR /sys/devices/system/cpu/cpu0/cpuidle/
  29. /sys/devices/system/cpu/cpu0/cpuidle/:
  30. total 0
  31. drwxr-xr-x 2 root root 0 Feb  8 10:42 state0
  32. drwxr-xr-x 2 root root 0 Feb  8 10:42 state1
  33. drwxr-xr-x 2 root root 0 Feb  8 10:42 state2
  34. drwxr-xr-x 2 root root 0 Feb  8 10:42 state3
  35.  
  36. /sys/devices/system/cpu/cpu0/cpuidle/state0:
  37. total 0
  38. -r--r--r-- 1 root root 4096 Feb  8 10:42 desc
  39. -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
  40. -r--r--r-- 1 root root 4096 Feb  8 10:42 latency
  41. -r--r--r-- 1 root root 4096 Feb  8 10:42 name
  42. -r--r--r-- 1 root root 4096 Feb  8 10:42 power
  43. -r--r--r-- 1 root root 4096 Feb  8 10:42 residency
  44. -r--r--r-- 1 root root 4096 Feb  8 10:42 time
  45. -r--r--r-- 1 root root 4096 Feb  8 10:42 usage
  46.  
  47. /sys/devices/system/cpu/cpu0/cpuidle/state1:
  48. total 0
  49. -r--r--r-- 1 root root 4096 Feb  8 10:42 desc
  50. -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
  51. -r--r--r-- 1 root root 4096 Feb  8 10:42 latency
  52. -r--r--r-- 1 root root 4096 Feb  8 10:42 name
  53. -r--r--r-- 1 root root 4096 Feb  8 10:42 power
  54. -r--r--r-- 1 root root 4096 Feb  8 10:42 residency
  55. -r--r--r-- 1 root root 4096 Feb  8 10:42 time
  56. -r--r--r-- 1 root root 4096 Feb  8 10:42 usage
  57.  
  58. /sys/devices/system/cpu/cpu0/cpuidle/state2:
  59. total 0
  60. -r--r--r-- 1 root root 4096 Feb  8 10:42 desc
  61. -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
  62. -r--r--r-- 1 root root 4096 Feb  8 10:42 latency
  63. -r--r--r-- 1 root root 4096 Feb  8 10:42 name
  64. -r--r--r-- 1 root root 4096 Feb  8 10:42 power
  65. -r--r--r-- 1 root root 4096 Feb  8 10:42 residency
  66. -r--r--r-- 1 root root 4096 Feb  8 10:42 time
  67. -r--r--r-- 1 root root 4096 Feb  8 10:42 usage
  68.  
  69. /sys/devices/system/cpu/cpu0/cpuidle/state3:
  70. total 0
  71. -r--r--r-- 1 root root 4096 Feb  8 10:42 desc
  72. -rw-r--r-- 1 root root 4096 Feb  8 10:42 disable
  73. -r--r--r-- 1 root root 4096 Feb  8 10:42 latency
  74. -r--r--r-- 1 root root 4096 Feb  8 10:42 name
  75. -r--r--r-- 1 root root 4096 Feb  8 10:42 power
  76. -r--r--r-- 1 root root 4096 Feb  8 10:42 residency
  77. -r--r--r-- 1 root root 4096 Feb  8 10:42 time
  78. -r--r--r-- 1 root root 4096 Feb  8 10:42 usage
  79. --------------------------------------------------------------------------------
  80.  
  81.  
  82. * desc : Small description about the idle state (string)
  83. * disable : Option to disable this idle state (bool) -> see note below
  84. * latency : Latency to exit out of this idle state (in microseconds)
  85. * residency : Time after which a state becomes more effecient than any
  86.   shallower state (in microseconds)
  87. * name : Name of the idle state (string)
  88. * power : Power consumed while in this idle state (in milliwatts)
  89. * time : Total time spent in this idle state (in microseconds)
  90. * usage : Number of times this state was entered (count)
  91.  
  92. Note:
  93. The behavior and the effect of the disable variable depends on the
  94. implementation of a particular governor. In the ladder governor, for
  95. example, it is not coherent, i.e. if one is disabling a light state,
  96. then all deeper states are disabled as well, but the disable variable
  97. does not reflect it. Likewise, if one enables a deep state but a lighter
  98. state still is disabled, then this has no effect.

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