The
powerd
utility monitors the system state and sets various power control options
accordingly.
It offers power-saving modes that can be
individually selected for operation on AC power or batteries.
|
| maximum
|
Choose the highest performance values.
May be abbreviated as
max.
|
| 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 aggressively, and
will maintain full frequency for longer.
May be abbreviated as
hadp.
|
|
The default mode is
adaptive
for battery power and
hiadaptive
for the rest.
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
|
Treat "nice" time as idle for the purpose of load calculation;
i.e. do not increase the CPU frequency if the CPU is only busy
with "nice" processes.
|
| -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.
|
| -s source
|
| |
Enforces method for AC line state refresh; by default, it is chosen
automatically.
The set of valid methods is
sysctl, devd
and
apm
(i386 only).
|
| -v
|
Verbose mode.
Messages about power changes will be printed to stdout and
powerd
will operate in the foreground.
|
|
