Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
POWERD(8)		FreeBSD	System Manager's Manual		     POWERD(8)

     powerd -- system power control utility

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

     The powerd	utility	monitors the system state and sets various power con-
     trol options accordingly.	It offers power-saving modes that can be indi-
     vidually selected for operation on	AC power or batteries.

     maximum	 Choose	the highest performance	values.	 May be	abbreviated as

     minimum	 Choose	the lowest performance values to get the most power
		 savings.  May be abbreviated as min.

     adaptive	 Attempt 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.  May	be abbreviated
		 as adp.

     hiadaptive	 Like adaptive mode, but tuned for systems where performance
		 and interactivity are more important than power consumption.
		 It increases frequency	faster,	reduces	frequency less aggres-
		 sively, and will maintain full	frequency for longer.  May be
		 abbreviated as	hadp.

     The default mode is adaptive for battery power and	hiadaptive for the

     powerd recognizes these 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.

     -m	freq	 Specifies the minimum frequency to throttle down to.

     -M	freq	 Specifies the maximum frequency to throttle up	to.

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

     -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/

     -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.

     acpi(4), apm(4), cpufreq(4)

     The powerd	utility	first appeared in FreeBSD 6.0.

     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.

     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	11.0			 July 4, 2013			  FreeBSD 11.0


Want to link to this manual page? Use this URL:

home | help