xref: /freebsd/usr.sbin/powerd/powerd.8 (revision 7a0a89d2cb29ee2c383600fa59e42d714a6dcbcb)
1.\" Copyright (c) 2005 Nate Lawson
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25.\" $FreeBSD$
26.\"
27.Dd December 24, 2008
28.Dt POWERD 8
29.Os
30.Sh NAME
31.Nm powerd
32.Nd "system power control utility"
33.Sh SYNOPSIS
34.Nm
35.Op Fl a Ar mode
36.Op Fl b Ar mode
37.Op Fl i Ar percent
38.Op Fl n Ar mode
39.Op Fl p Ar ival
40.Op Fl P Ar pidfile
41.Op Fl r Ar percent
42.Op Fl v
43.Sh DESCRIPTION
44The
45.Nm
46utility monitors the system state and sets various power control options
47accordingly.
48It offers three modes (maximum, minimum, and adaptive) that can be
49individually selected while on AC power or batteries.
50The modes maximum, minimum, adaptive and hiadaptive may be abbreviated
51max, min, adp, hadp.
52.Pp
53Maximum mode chooses the highest performance values.
54Minimum mode selects the lowest performance values to get the most power
55savings.
56Adaptive mode attempts to strike a balance by degrading performance when
57the system appears idle and increasing it when the system is busy.
58It offers a good balance between a small performance loss for greatly
59increased power savings.
60Hiadaptive mode is alike adaptive mode, but tuned for systems where
61performance and interactivity are more important then power consumption.
62It rises frequency faster, drops slower and keeps twice lower CPU load.
63The default mode is adaptive for battery power and hiadaptive for the rest.
64.Pp
65The
66.Nm
67utility recognizes the following runtime options:
68.Bl -tag -width ".Fl r Ar percent"
69.It Fl a Ar mode
70Selects the
71.Ar mode
72to use while on AC power.
73.It Fl b Ar mode
74Selects the
75.Ar mode
76to use while on battery power.
77.It Fl i Ar percent
78Specifies the CPU load percent level when adaptive
79mode should begin to degrade performance to save power.
80The default is 50% or lower.
81.It Fl n Ar mode
82Selects the
83.Ar mode
84to use normally when the AC line state is unknown.
85.It Fl p Ar ival
86Specifies a different polling interval (in milliseconds) for AC line state
87and system idle levels.
88The default is 250 ms.
89.It Fl P Ar pidfile
90Specifies an alternative file in which the process ID should be stored.
91The default is
92.Pa /var/run/powerd.pid .
93.It Fl r Ar percent
94Specifies the CPU load percent level where adaptive
95mode should consider the CPU running and increase performance.
96The default is 75% or higher.
97.It Fl v
98Verbose mode.
99Messages about power changes will be printed to stdout and
100.Nm
101will operate in the foreground.
102.El
103.Sh SEE ALSO
104.Xr acpi 4 ,
105.Xr apm 4 ,
106.Xr cpufreq 4
107.Sh HISTORY
108The
109.Nm
110utility first appeared in
111.Fx 6.0 .
112.Sh AUTHORS
113.An -nosplit
114.An Colin Percival
115first wrote
116.Nm estctrl ,
117the utility that
118.Nm
119is based on.
120.An Nate Lawson
121then updated it for
122.Xr cpufreq 4 ,
123added features, and wrote this manual page.
124.Sh BUGS
125The
126.Nm
127utility should also power down idle disks and other components besides the CPU.
128.Pp
129If
130.Nm
131is used with
132.Pa power_profile ,
133they may override each other.
134.Pp
135The
136.Nm
137utility
138should probably use the
139.Xr devctl 4
140interface instead of polling for AC line state.
141