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POWERD(8)		FreeBSD	System Manager's Manual		     POWERD(8)

NAME
     powerd -- system power control utility

SYNOPSIS
     powerd [-a	mode] [-b mode]	[-i percent] [-n mode] [-p ival] [-P pidfile]
	    [-r	percent] [-v]

DESCRIPTION
     The powerd	utility	monitors the system state and sets various power con-
     trol options accordingly.	It offers three	modes (maximum,	minimum, and
     adaptive) that can	be individually	selected while on AC power or batter-
     ies.  The modes maximum, minimum, adaptive	and hiadaptive may be abbrevi-
     ated max, min, adp, hadp.

     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.  Hiadaptive mode is alike	adaptive mode, but
     tuned for systems where performance and interactivity are more important
     then power	consumption.  It rises frequency faster, drops slower and
     keeps twice lower CPU load.  The default mode is adaptive for battery
     power and hiadaptive for the rest.

     The powerd	utility	recognizes the following runtime options:

     -a	mode	 Selects the mode to use while on AC power.

     -b	mode	 Selects the mode to use while on battery power.

     -i	percent	 Specifies the CPU load	percent	level when adaptive mode
		 should	begin to degrade performance to	save power.  The
		 default is 50%	or lower.

     -n	mode	 Selects the mode to use normally when the AC line state is
		 unknown.

     -p	ival	 Specifies a different polling interval	(in milliseconds) for
		 AC line state and system idle levels.	The default is 250 ms.

     -P	pidfile	 Specifies an alternative file in which	the process ID should
		 be stored.  The default is /var/run/powerd.pid.

     -r	percent	 Specifies the CPU load	percent	level where adaptive mode
		 should	consider the CPU running and increase performance.
		 The default is	75% or higher.

     -v		 Verbose mode.	Messages about power changes will be printed
		 to stdout and powerd will operate in the foreground.

SEE ALSO
     acpi(4), apm(4), cpufreq(4)

HISTORY
     The powerd	utility	first appeared in FreeBSD 6.0.

AUTHORS
     Colin Percival first wrote	estctrl, the utility that powerd is based on.
     Nate Lawson then updated it for cpufreq(4), added features, and wrote
     this manual page.

BUGS
     The powerd	utility	should also power down idle disks and other components
     besides the CPU.

     If	powerd is used with power_profile, they	may override each other.

     The powerd	utility	should probably	use the	devctl(4) interface instead of
     polling for AC line state.

FreeBSD	10.1		       December	24, 2008		  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS | BUGS

Want to link to this manual page? Use this URL:
<http://www.freebsd.org/cgi/man.cgi?query=powerd&sektion=8&manpath=FreeBSD+8.0-RELEASE>

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