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32 .Nd "system power control utility"
48 utility monitors the system state and sets various power control options
50 It offers four modes (maximum, minimum, adaptive and hiadaptive) that can be
51 individually selected while on AC power or batteries.
52 The modes maximum, minimum, adaptive and hiadaptive may be abbreviated
55 Maximum mode chooses the highest performance values.
56 Minimum mode selects the lowest performance values to get the most power
58 Adaptive mode attempts to strike a balance by degrading performance when
59 the system appears idle and increasing it when the system is busy.
60 It offers a good balance between a small performance loss for greatly
61 increased power savings.
62 Hiadaptive mode is like adaptive mode, but tuned for systems where
63 performance and interactivity are more important than power consumption.
64 It increases frequency faster, reduces the frequency less aggressively and
65 will maintain full frequency for longer.
66 The default mode is adaptive for battery power and hiadaptive for the rest.
70 utility recognizes the following runtime options:
71 .Bl -tag -width ".Fl r Ar percent"
75 to use while on AC power.
79 to use while on battery power.
81 Specifies the CPU load percent level when adaptive
82 mode should begin to degrade performance to save power.
83 The default is 50% or lower.
85 Specifies the minimum frequency to throttle down to.
87 Specifies the maximum frequency to throttle up to.
91 to use normally when the AC line state is unknown.
93 Specifies a different polling interval (in milliseconds) for AC line state
94 and system idle levels.
95 The default is 250 ms.
97 Specifies an alternative file in which the process ID should be stored.
99 .Pa /var/run/powerd.pid .
101 Specifies the CPU load percent level where adaptive
102 mode should consider the CPU running and increase performance.
103 The default is 75% or higher.
106 Messages about power changes will be printed to stdout and
108 will operate in the foreground.
117 utility first appeared in
130 added features, and wrote this manual page.
134 utility should also power down idle disks and other components besides the CPU.
140 they may override each other.
145 should probably use the
147 interface instead of polling for AC line state.