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$FreeBSD: head/usr.sbin/powerd/powerd.8 179932 2008-06-22 17:52:57Z obrien $
.Dd November 6, 2005 .Dt POWERD 8 .Os .Sh NAME .Nm powerd .Nd "system power control utility" .Sh SYNOPSIS .Nm .Op Fl a Ar mode .Op Fl b Ar mode .Op Fl i Ar percent .Op Fl n Ar mode .Op Fl p Ar ival .Op Fl P Ar pidfile .Op Fl r Ar percent .Op Fl v .Sh DESCRIPTION The .Nm utility monitors the system state and sets various power control options accordingly. It offers three modes (maximum, minimum, and adaptive) that can be individually selected while on AC power or batteries. The modes maximum, minimum, and adaptive may be abbreviated max, min, adp.
p Maximum mode chooses the highest performance values. Minimum mode selects the lowest performance values to get the most power savings. Adaptive mode attempts to strike a balance by degrading performance when the system appears idle and increasing it when the system is busy. It offers a good balance between a small performance loss for greatly increased power savings. The default mode is adaptive.
p The .Nm utility recognizes the following runtime options: l -tag -width ".Fl r Ar percent" t Fl a Ar mode Selects the .Ar mode to use while on AC power. t Fl b Ar mode Selects the .Ar mode to use while on battery power. t Fl i Ar percent Specifies the CPU idle percent level when adaptive mode should begin to degrade performance to save power. The default is 90% or higher. t Fl n Ar mode Selects the .Ar mode to use normally when the AC line state is unknown. t Fl p Ar ival Specifies a different polling interval (in milliseconds) for AC line state and system idle levels. The default is 500 ms. t Fl P Ar pidfile Specifies an alternative file in which the process ID should be stored. The default is
a /var/run/powerd.pid . t Fl r Ar percent Specifies the CPU idle percent level where adaptive mode should consider the CPU running and increase performance. The default is 65% or lower. t Fl v Verbose mode. Messages about power changes will be printed to stdout and .Nm will operate in the foreground. .El .Sh SEE ALSO .Xr acpi 4 , .Xr apm 4 , .Xr cpufreq 4 .Sh HISTORY The .Nm utility first appeared in .Fx 6.0 . .Sh AUTHORS .An -nosplit .An Colin Percival first wrote .Nm estctrl , the utility that .Nm is based on. .An Nate Lawson then updated it for .Xr cpufreq 4 , added features, and wrote this manual page. .Sh BUGS The .Nm utility should also power down idle disks and other components besides the CPU.
p If .Nm is used with
a power_profile , they may override each other.
p The .Nm utility should probably use the .Xr devctl 4 interface instead of polling for AC line state.