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Various governors can be set to affect the power management policy:
userspace
powersave,
,
and
the balance between power saving and performance can be adjusted:
To display the current governor, use the cat command as shown in
Example 3-3.
To scale the frequency, and change the governor from the default ondemand to
userspace (not case-sensitive), use the command shown in Example 3-4.
To change to another frequency, use the command shown in Example 3-5.
Example 3-3 Command to display the current scaling governor
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
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Example 3-4 Change the governor to USERSPACE
cpufreq-set -g USERSPACE
Example 3-5 Command to change the frequency
# cpufreq-info -f -c 5
1862000
# cpufreq-set -c 5 -f 2128000
# cpufreq-info -f -c 5
2128000
Windows Server 2003
To utilize processor performance states, Windows Server 2003 must be using a
power policy that enables DBS. By default, the power scheme Always On is set.
This has the effect of running the system at full power regardless of workload
demands. Windows includes a power policy named Server Balanced Processor
Power and Performance that implements DBS by using the entire range of
performance states that are available on the system.
Select the power scheme through either of the following methods:
Command line, by using the powercfg.exe executable command:
powercfg.exe -s "Server Balanced Processor Power and Performance"
Power Options Properties windows, shown in Figure 3-10 on page 104.
performance.
Depending on the configured governor,
Chapter 3. Hardware configuration
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103
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