System information
140 System Analysis and Tuning Guide
Monitoring Power Consumption with powerTOP (page145)
powerTOP combines various sources of information (analysis of programs, de-
vice drivers, kernel options, amounts and sources of interrupts waking up proces-
sors from sleep states) and shows them in one screen. The tool helps you to iden-
tify the reasons for unnecessary high power consumption (for example, process-
es that are mainly responsible for waking up a processor from its idle state) and to
optimize your system settings to avoid these.
11.3.1 Using the cpufrequtils Tools
NOTE: cpupower and cpufrequtils
All functions of cpufrequtils are also covered by cpupower—a new set
of tools that is more powerful and provides additional features. As cpupower
will replace cpufrequtils sooner or later, we advise to switch to cpupow-
er soon and to adjust your scripts accordingly.
After you have installed the cpufrequtils package, you can make use of the
cpufreq-info and cpufreq-set command line tools.
11.3.1.1 Viewing Current Settings with cpufreq-
info
The cpufreq-info command helps you to retrieve CPUfreq kernel information.
Run without any options, it collects the information available for your system:
Example11.1: Example Output of cpufreq-info
cpufrequtils 004: cpufreq-info (C) Dominik Brodowski 2004-2006
Report errors and bugs to http://bugs.opensuse.org, please.
analyzing CPU 0:
driver: acpi-cpufreq
CPUs which need to switch frequency at the same time: 0
hardware limits: 2.80 GHz - 3.40 GHz
available frequency steps: 3.40 GHz, 2.80 GHz
available cpufreq governors: conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 2.80 GHz and 3.40 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 3.40 GHz.
analyzing CPU 1:
driver: acpi-cpufreq
CPUs which need to switch frequency at the same time: 1
hardware limits: 2.80 GHz - 3.40 GHz