.\" (c) Copyright 2010 by Matthew Dillon and Dima Ruban.  Permission to
.\"    use and distribute based on the DragonFly copyright.
.\"
.Dd July 17, 2015
.Dt POWERD 8
.Os
.Sh NAME
.Nm powerd
.Nd simple CPU performance control and battery life monitor
.Sh SYNOPSIS
.Nm
.Op Fl cdeftQ
.Op Fl h Ar highest_freq
.Op Fl l Ar lowest_freq
.Op Fl p Ar hysteresis
.Op Fl r Ar poll_time
.Op Fl u Ar trigger_up
.Op Fl B Ar minimum_battery_life
.Op Fl L Ar battery_life_linger
.Op Fl P Ar battery_poll_interval
.Op Fl T Ar sample_time
.Sh DESCRIPTION
The
.Nm
daemon monitors the CPU load and automatically adjusts the CPU
performance up or down accordingly.
.Pp
The
.Nm
also monitors battery life.
If the battery life is low
(less then or equal to 2% by default),
.Nm
will send audio alert immediately,
and shutdown the machine after lingering for a little while
(60 seconds by default).
.Pp
The options are as follows:
.Bl -tag -width ".Fl p Ar hysteresis"
.It Fl c
Enable mwait C-state hint adjustment,
if it is available.
.It Fl d
Debug option.
Causes
.Nm
to not go to the background and prints some debug output to
.Va stdout .
.It Fl e
Enable Intel Performance and Energy Bias Hint adjustment,
if it is available.
.It Fl f
Disable CPU power domain frequency adjustment.
CPU power domain frequency adjustment does not reduce CPU power consumption
much
(if any)
on some of the modern Intel CPUs,
when the CPU is idle.
.It Fl h Ar highest_freq
If CPU power domain frequency adjustment is enabled,
then frequency of CPU power domains will not be set to a value higher
than the specified limit.
(unit: MHz)
.It Fl l Ar lowest_freq
If CPU power domain frequency adjustment is enabled,
then frequency of CPU power domains will not be set to a value lower
than the specified limit.
(unit: MHz)
.It Fl p Ar hysteresis
Percent of the upper limit to subtract as an hysteresis value to scale
down to the min performance.
The default is 10
(meaning 10%).
.It Fl r Ar poll_time
Polling time in seconds.
Default is 1.0.
Setting this value lower will poll for load changes faster.
For example,
a workstation might want to use 0.2 or 0.4.
.Nm can become unstable if you make this value too small.
.It Fl t
Turbo mode.
Disables switching to turbo mode as maximum frequency completely.
Switching to turbo mode as maximum frequency is enabled by default,
if the CPU supports it.
.It Fl u Ar trigger_up
Per CPU load limit in percent to force maximum performance.
The default is 25
(meaning an instantanious load of 0.25 on a single cpu).
The load is calculated over 3 polls.
It is suggested that this value not be made lower than around 7.
.It Fl B Ar minimum_battery_life
If battery life is less than or equal to the specified value,
the machine will start shutting down process.
Default is 2
(2% battery life left).
.It Fl L Ar battery_life_linger
If battery life is less than or equal to the configured value,
shutting down the machine will be delayed by the specified value.
During the delay,
alert message will be logged to the console,
and audio alert will be alarmed.
If AC line is plugged in during this delay,
shutting down process will be cancelled.
Default is 60 seconds.
.It Fl P Ar battery_poll_interval
Poll the battery life at the specified interval.
If 0 is specified,
battery life monitoring will be disabled.
Default is 5 seconds.
.It Fl Q
Don't alarm audio alert,
if the battery life is low.
.It Fl T Ar sample_time
Total sample interval in seconds.
Default is 8.0.
This effects how quickly powerd ratchets down the performance
and cpus on an idle machine.
Longer times will ratchet down more slowly.
For example,
a workstation might want to use a value of 30.0.
.El
.Sh EXAMPLES
The defaults work well for servers but a workstation user might want
to use something like the following in their
.Pa /etc/rc.conf
to ratchet up the machine more quickly in response to spike loads
(such as when you are browsing).
.Pp
.Li powerd_enable="YES"
.Pp
.Li powerd_flags="-u 7 -r 0.2 -T 60"
.Sh DIAGNOSTICS
The
.Nm
utility will exit with a non-zero code if the required sysctls are not
present.
.Sh SEE ALSO
.Xr acpi 4 ,
.Xr perfbias 4
.Sh HISTORY
The
.Nm
command first appeared in
.Dx 2.7 .
.Sh BUGS
I'm shocked I tell you,
shocked that there might be bugs in this program!