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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] [-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 hiadaptive
     may be abbreviated 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 like adaptive mode, but
     tuned for systems where performance and interactivity are more important
     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
                       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 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 11.0-PRERELEASE        December 21, 2009       FreeBSD 11.0-PRERELEASE

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

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