xref: /freebsd/usr.sbin/powerd/powerd.8 (revision f7c4bd95ba735bd6a5454b4953945a99cefbb80c)
1.\" Copyright (c) 2005 Nate Lawson
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
6.\" are met:
7.\" 1. Redistributions of source code must retain the above copyright
8.\"    notice, this list of conditions and the following disclaimer.
9.\" 2. Redistributions in binary form must reproduce the above copyright
10.\"    notice, this list of conditions and the following disclaimer in the
11.\"    documentation and/or other materials provided with the distribution.
12.\"
13.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23.\" SUCH DAMAGE.
24.\"
25.\" $FreeBSD$
26.\"
27.Dd November 6, 2005
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, and adaptive may be abbreviated max, min, adp.
51.Pp
52Maximum mode chooses the highest performance values.
53Minimum mode selects the lowest performance values to get the most power
54savings.
55Adaptive mode attempts to strike a balance by degrading performance when
56the system appears idle and increasing it when the system is busy.
57It offers a good balance between a small performance loss for greatly
58increased power savings.
59The default mode is
60adaptive.
61.Pp
62The
63.Nm
64utility recognizes the following runtime options:
65.Bl -tag -width ".Fl r Ar percent"
66.It Fl a Ar mode
67Selects the
68.Ar mode
69to use while on AC power.
70.It Fl b Ar mode
71Selects the
72.Ar mode
73to use while on battery power.
74.It Fl i Ar percent
75Specifies the CPU idle percent level when
76adaptive
77mode should begin to degrade performance to save power.
78The default is 90% or higher.
79.It Fl n Ar mode
80Selects the
81.Ar mode
82to use normally when the AC line state is unknown.
83.It Fl p Ar ival
84Specifies a different polling interval (in milliseconds) for AC line state
85and system idle levels.
86The default is 500 ms.
87.It Fl P Ar pidfile
88Specifies an alternative file in which the process ID should be stored.
89The default is
90.Pa /var/run/powerd.pid .
91.It Fl r Ar percent
92Specifies the CPU idle percent level where
93adaptive
94mode should consider the CPU running and increase performance.
95The default is 65% or lower.
96.It Fl v
97Verbose mode.
98Messages about power changes will be printed to stdout and
99.Nm
100will operate in the foreground.
101.El
102.Sh SEE ALSO
103.Xr acpi 4 ,
104.Xr apm 4 ,
105.Xr cpufreq 4
106.Sh HISTORY
107The
108.Nm
109utility first appeared in
110.Fx 6.0 .
111.Sh AUTHORS
112.An -nosplit
113.An Colin Percival
114first wrote
115.Nm estctrl ,
116the utility that
117.Nm
118is based on.
119.An Nate Lawson
120then updated it for
121.Xr cpufreq 4 ,
122added features, and wrote this manual page.
123.Sh BUGS
124The
125.Nm
126utility should also power down idle disks and other components besides the CPU.
127.Pp
128If
129.Nm
130is used with
131.Pa power_profile ,
132they may override each other.
133.Pp
134The
135.Nm
136utility
137should probably use the
138.Xr devctl 4
139interface instead of polling for AC line state.
140