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POWERD(8) BSD 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. The modes maximum, minimum, adaptive and hiadaptive may be abbrevi- ated max, min, adp, hadp. Maximum mode chooses the highest performance values. Minimum mode se- lects the lowest performance values to get the most power savings. Adap- tive 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 alike adaptive mode, but tuned for systems where performance and interactivity are more important then power consumption. It rises frequency faster, drops slower and keeps twice lower CPU load. The default mode is adaptive for battery power and hi- adaptive 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 de- fault is 50% or lower. -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. BSD December 24, 2008 BSD
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY | AUTHORS | BUGS
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