Use Cpufreq to temporarily adjust the frequency of CPU

#32位系统
Yum Install-y cpufreq-utils.i386
#64位系统
Yum Install-y cpufreq-utils.x86_64

#查看当前CPU工作频率和状态
Cpufreq-info

A) View CPU type, current frequency, support frequency, operating mode, etc.
Cpufreq-info, Cpufreq-selector, Cpufreq-set.

[Root@apiof.com ~]# Cpufreq-info
Cpufrequtils 007:cpufreq-info (C) Dominik Brodowski 2004-2009
The errors and bugs to cpufreq@vger.kernel.org.
Analyzing CPU 0:
Driver:powernow-k8
CPUs which run at the same hardware frequency:0
CPUs which need to have their frequency from coordinated by software:0
Maximum transition latency:1000 ns.
Hardware limits:800 MHz-1.60 GHz
Available Frequency steps:1.60 GHz, 1.28 GHz, and MHz
Available Cpufreq Governors:ondemand, userspace, performance
Current policy:frequency should are within MHz and 1.60 GHz.
The governor "OnDemand" may decide which speed to use
Within this range.
Current CPU frequency is-asserted by call to hardware.
Analyzing CPU 1:
Driver:powernow-k8
CPUs which run at the same hardware frequency:1
CPUs which need to have their frequency from coordinated by software:1
Maximum transition latency:1000 ns.
Hardware limits:800 MHz-1.60 GHz
Available Frequency steps:1.60 GHz, 1.28 GHz, and MHz
Available Cpufreq Governors:ondemand, userspace, performance
Current policy:frequency should are within MHz and 1.60 GHz.
The governor "OnDemand" may decide which speed to use
Within this range.
Current CPU frequency is-asserted by call to hardware.

b Select the CPU you want to adjust
sudo cpufreq-selector-c CPU number
Or
sudo cpufreq-set-c CPU number

A choice may be made for dual or multi-core CPUs. Mine is not a double core, can not experiment, but also please have duo Core Friend experiment and Post report.

c) Adjust CPU frequency
sudo cpufreq-selector-f the frequency you need
Or
sudo cpufreq-set-f the frequency you need

Note that the frequency here must be in khz, and is the frequency that can be reached (that is, with cpufreq-info to see each frequency), CPU frequency = multiplier x FSB. The following are usually the same as the frequencies involved.

d) Adjust the CPU frequency upper and lower limits
sudo cpufreq-set-d frequency lower
sudo cpufreq-set-u frequency limit

As a result, you may be able to reduce frequency or overclocking the CPU. Some people are going to be tempted, hehe.

e) Tuning CPU operating mode
sudo cpufreq-selecotr-g mode
Or
Suod cpufreq-set-g Mode
Here, the pattern is the supported pattern that is seen after performing the Cpufreq-info. For example, my support for the following kinds: powersave, userspace, OnDemand, conservative, performance.

    PowerSave is the so-called "power saving" mode that will only maintain the lowest frequency in any case;
    userspace,   is the pattern of custom frequencies. This is automatically changed when you set a specific frequency;
    OnDemand, default mode. A CPU to calculate the task, it will immediately reach the maximum frequency of operation, and so on immediately return to the lowest frequency;
    Conservative, translated into a conservative (mean) mode, will automatically adjust the frequency of the lower bound, The difference between the OnDemand is that it will be on demand, not the highest frequency;
    performance, as the name suggests, focuses on efficiency, and keeps running at maximum frequency anyway.