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

NAME
       powerd -- system	power control utility

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

DESCRIPTION
       The powerd utility monitors the system state  and  sets	various	 power
       control	options	 accordingly.  It offers four modes (maximum, minimum,
       adaptive	and hiadaptive)	that can be individually selected while	on  AC
       power  or  batteries.  The modes	maximum, minimum, adaptive and hiadap-
       tive may	be abbreviated max, min, adp, hadp.

       Maximum mode chooses the	highest	performance values.  Minimum mode  se-
       lects  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 like  adaptive  mode,  but
       tuned  for  systems where performance and interactivity are more	impor-
       tant than power consumption.  It	increases  frequency  faster,  reduces
       the  frequency  less  aggressively and will maintain full frequency for
       longer.	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 de-
		   fault 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
		   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	compo-
       nents 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.

GNU			       December	21, 2009		     POWERD(8)

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

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<https://man.freebsd.org/cgi/man.cgi?query=powerd&manpath=FreeBSD+9.1-RELEASE>

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