CentOS CPU Scaling

CPU Scaling allows the processor to adjust speed on demand. CPUfreq governor defines the speed and power usage of a processor. The different types of governors are:

cpufreq_performance – for heavy workloads, always uses the highest cpu frequency, cost is power
cpufreq_powersave – uses the lowest cpu frequency, provides the most power savings, cost is performance
cpufreq_ondemand – adjusts cpu frequency based on need, can save power when system is idle, while ramping up when system is not idle, cost is latency while switching
cpufreq_userspace – allows any process running as root to set the frequency, most configurable
cpufreq_conservative – similar to ondemand, however unlike the ondemand governor which switches between lowest and highest, conservative performs gradual change

To use cpu governor run ‘sudo yum install cpupowerutils -y’.
To view available governors use ‘cpupower frequency-info –governors’
To add a particular driver use ‘modprobe ‘, as in ‘modprobe cpufreq_ondemand’.
To enable the given driver use ‘cpupower frequency-set –governor [governor]’, as in ‘cpupower frequency-set –governor cpufreq_ondemand’
To view CPU speed and policy use ‘ cpupower frequency-info’.
To set a frequency use ‘cpupower frequency-set’.

To view available drivers for cpu scaling checking ‘ls /lib/modules/[kernel version]/kernel/arch/[architecture]/kernel/cpu/cpufreq/’ should be a good start.

For additional information view https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Power_Management_Guide/cpufreq_governors.html.

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