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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.

     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.

     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 idle percent level when adaptive mode
                 should begin to degrade performance to save power.  The
                 default is 90% or higher.

     -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 500 ms.

     -P          Specify an alternative file in which to store the process ID.
                 The default is /var/run/powerd.pid.

     -r percent  Specifies the CPU idle percent level where adaptive mode
                 should consider the CPU running and increase performance.
                 The default is 65% or lower.

     -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 6.2                     April 10, 2005                     FreeBSD 6.2

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+6.2-RELEASE>

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