cpufreqd(8) - Linux man page

Name

cpufreqd - intelligently monitor and manipulate CPU frequency

Synopsis

cpufreqd [-Dhv] [-f filename] [-V verbosity]

Description

cpufreqd is used to monitor the status of the battery and adjust the frequency of the CPU accordingly in order to preserve battery power while providing optimal performance. The behaviour of the daemon is fully configurable. Logs are reported through syslogd.

Parameters

-D, --no-daemon: stay in foreground (used to debug).
-f filename, --file=filename: Specify the configuration file to read. The default is /etc/cpufreqd.conf.
-h, --help: Display command line help.
-v, --version: Display the version number of the daemon.
-V, --verbosity: verbosity level from 0 (less verbose) to 7 (most verbose). Default verbosity is 4

Signals

SIGHUP: This lets cpufreqd perform a re-initialization. The configuration file (default is /etc/cpufreqd.conf) will be re-read and probes re-done.
SIGINT, SIGTERM: cpufreqd will terminate.

Examples

/usr/sbin/cpufreqd -D

Notes

Some ACPI implementations are very cpu-consuming when reading the info file of system batteries. Cpufreqd implements a simple workaround that avoids reading that file except on initialization or reinitialization. This has the effect of needing to send an HUP signal if inserting a new battery, otherwise battery measurement won't be correct.

Files

/sys/devices/system/cpu/cpu*/cpufreq: 2.6 kernel cpu frequency interface
/proc/cpufreq: 2.4 kernel cpu frequency interface
/proc/apm: kernel power management interface (APM)
/proc/acpi: kernel power management interface (ACPI)
/proc/pmu: kernel power management interface (PMU)
/etc/cpufreqd.conf: cpufreqd configuration file

Bugs

Multiple CPUs are not supported. Battery can only be specified in percent, not in minutes remaining.

Author

George Staikos <staikos@0wned.org>
Mattia Dongili <dongili@supereva.it>
Rene Rebe <rene@rocklinux.org>