DragonFly On-Line Manual Pages

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

NAME

powerd -- simple CPU performance control and battery life monitor

SYNOPSIS

powerd [-cdeftQ] [-h highest_freq] [-l lowest_freq] [-p hysteresis] [-r poll_time] [-u trigger_up] [-B minimum_battery_life] [-L battery_life_linger] [-P battery_poll_interval] [-T sample_time]

DESCRIPTION

The powerd daemon monitors the CPU load and automatically adjusts the CPU performance up or down accordingly. The powerd also monitors battery life. If the battery life is low (less then or equal to 2% by default), powerd will send audio alert immedi- ately, and shutdown the machine after lingering for a little while (60 seconds by default). The options are as follows: -c Enable mwait C-state hint adjustment, if it is available. -d Debug option. Causes powerd to not go to the background and prints some debug output to stdout. -e Enable Intel Performance and Energy Bias Hint adjustment, if it is available. -f Disable CPU power domain frequency adjustment. CPU power domain frequency adjustment does not reduce CPU power con- sumption much (if any) on some of the modern Intel CPUs, when the CPU is idle. -h 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) -l 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) -p 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%). -r poll_time Polling time in seconds. Default is 1.0. Setting this value lower will poll for load changes faster. For exam- ple, a workstation might want to use 0.2 or 0.4. can become unstable if you make this value too small. -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. -u trigger_up Per CPU load limit in percent to force maximum perfor- mance. 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. -B 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). -L 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. -P 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. -Q Don't alarm audio alert, if the battery life is low. -T 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.

EXAMPLES

The defaults work well for servers but a workstation user might want to use something like the following in their /etc/rc.conf to ratchet up the machine more quickly in response to spike loads (such as when you are browsing). powerd_enable="YES" powerd_flags="-u 7 -r 0.2 -T 60"

DIAGNOSTICS

The powerd utility will exit with a non-zero code if the required sysctls are not present.

SEE ALSO

acpi(4), perfbias(4)

HISTORY

The powerd command first appeared in DragonFly 2.7.

BUGS

I'm shocked I tell you, shocked that there might be bugs in this program! DragonFly 4.3 July 17, 2015 DragonFly 4.3