xref: /freebsd/usr.sbin/powerd/powerd.8 (revision cf2280aca702edef4dbccf8d1e1a8ac01c8565e7)
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25.\" $FreeBSD$
26.\"
27.Dd December 21, 2009
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 m Ar freq
39.Op Fl M Ar freq
40.Op Fl n Ar mode
41.Op Fl p Ar ival
42.Op Fl P Ar pidfile
43.Op Fl r Ar percent
44.Op Fl v
45.Sh DESCRIPTION
46The
47.Nm
48utility monitors the system state and sets various power control options
49accordingly.
50It offers four modes (maximum, minimum, adaptive and hiadaptive) that can be
51individually selected while on AC power or batteries.
52The modes maximum, minimum, adaptive and hiadaptive may be abbreviated
53max, min, adp, hadp.
54.Pp
55Maximum mode chooses the highest performance values.
56Minimum mode selects the lowest performance values to get the most power
57savings.
58Adaptive mode attempts to strike a balance by degrading performance when
59the system appears idle and increasing it when the system is busy.
60It offers a good balance between a small performance loss for greatly
61increased power savings.
62Hiadaptive mode is like adaptive mode, but tuned for systems where
63performance and interactivity are more important than power consumption.
64It increases frequency faster, reduces the frequency less aggressively and
65will maintain full frequency for longer.
66The default mode is adaptive for battery power and hiadaptive for the rest.
67.Pp
68The
69.Nm
70utility recognizes the following runtime options:
71.Bl -tag -width ".Fl r Ar percent"
72.It Fl a Ar mode
73Selects the
74.Ar mode
75to use while on AC power.
76.It Fl b Ar mode
77Selects the
78.Ar mode
79to use while on battery power.
80.It Fl i Ar percent
81Specifies the CPU load percent level when adaptive
82mode should begin to degrade performance to save power.
83The default is 50% or lower.
84.It Fl m Ar freq
85Specifies the minimum frequency to throttle down to.
86.It Fl M Ar freq
87Specifies the maximum frequency to throttle up to.
88.It Fl n Ar mode
89Selects the
90.Ar mode
91to use normally when the AC line state is unknown.
92.It Fl p Ar ival
93Specifies a different polling interval (in milliseconds) for AC line state
94and system idle levels.
95The default is 250 ms.
96.It Fl P Ar pidfile
97Specifies an alternative file in which the process ID should be stored.
98The default is
99.Pa /var/run/powerd.pid .
100.It Fl r Ar percent
101Specifies the CPU load percent level where adaptive
102mode should consider the CPU running and increase performance.
103The default is 75% or higher.
104.It Fl v
105Verbose mode.
106Messages about power changes will be printed to stdout and
107.Nm
108will operate in the foreground.
109.El
110.Sh SEE ALSO
111.Xr acpi 4 ,
112.Xr apm 4 ,
113.Xr cpufreq 4
114.Sh HISTORY
115The
116.Nm
117utility first appeared in
118.Fx 6.0 .
119.Sh AUTHORS
120.An -nosplit
121.An Colin Percival
122first wrote
123.Nm estctrl ,
124the utility that
125.Nm
126is based on.
127.An Nate Lawson
128then updated it for
129.Xr cpufreq 4 ,
130added features, and wrote this manual page.
131.Sh BUGS
132The
133.Nm
134utility should also power down idle disks and other components besides the CPU.
135.Pp
136If
137.Nm
138is used with
139.Pa power_profile ,
140they may override each other.
141.Pp
142The
143.Nm
144utility
145should probably use the
146.Xr devctl 4
147interface instead of polling for AC line state.
148