All SuperH processors supporting rate rounding through the clock. This would be best used in a battery powered environment. If you see most or all of modules that where listed in the cpufreq directory then your done. If not then use the CPU info you found and figure out which module you need to load. Boosting means overclocking the processor, although under controlled conditions.

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If you have these modules then they may already be running. In order to estimate the current CPU load, it measures the time elapsed between consecutive invocations of its worker routine and computes the fraction of that time in which the given CPU was not idle. That directory contains a policyX subdirectory where X represents an integer number for every policy object maintained by the CPUFreq core. If the AMD frequency sensitivity powersave bias driver is loaded, the value of this attribute is by default and it is used in a different way.

If it is software-based e.

CPU frequency scaling

Now that they are loaded you will want to load them on boot. One of the reasons you might want to do this would be to save energy.

Those attributes, referred to as governor tunables, can be either global system-wide or per-policy, depending on the scaling driver in use. It estimates the CPU load in the same way as the ondemand governor described above, but the CPU frequency selection algorithm implemented by it is different. This governor does not do anything by itself. Phoronix Test Suite OpenBenchmarking. It defines the basic framework in which the other components operate.


Scaling governors implement algorithms to estimate the required CPU capacity. You can go about setting these on reboot a few ways. Move on to the next section.

Remove any userspace CPU scaling programs There are some userspace programs cpjfreq can be run to scale the processors frequency. This governor exposes the following tunables: Namely, it avoids changing the frequency significantly over short time intervals which may not be suitable for systems with limited power supply capacity e.

Some governors expose sysfs attributes to control or fine-tune the scaling algorithms implemented by them.

Otherwise, the frequency will not be changed. Supported Architectures and Processors. In either case the name of the subdirectory containing the governor tunables is the name of the governor providing them. These will help you find out things like the current frequency of your processor or what available frequencies your CPU can scale to.

Since root executes rc.

CPU Performance Scaling — The Linux Kernel documentation

If it is hardware-based e. As a last resort if any of these don’t work you can try the generic one for ACPI. Performance governor – CPU runs at max frequency regardless of load.

It also may not be physically possible to maintain maximum CPU capacity for too long for thermal or power supply capacity reasons or similar. The cpb knob is never present for any processors without the underlying hardware feature e.


Intel Pentium 4Intel Xeon. Some processors support a mechanism to raise the operating frequency of some cores in a multicore package temporarily and above the sustainable frequency threshold for the whole package under certain conditions, for example if the whole chip is not fully utilized and below its intended thermal or power budget.

This means that either the hardware can be put into states in which it is able to trigger boosting in the hardware-based caseor the software is allowed to trigger boosting in the software-based case.

CPUFreq provides generic scaling governors that can be used with all scaling drivers. The scaling driver may be invoked directly from scheduler context or asynchronously, via a kernel thread or workqueue, depending on the configuration and capabilities of the scaling driver and the governor.

Documentation/cpu-freq/ – kernel/common – Git at Google

Core i9 XE vs. The frequency boost mechanism is generally intended to help to achieve optimum CPU performance on time scales below software resolution e. Minimum time in microseconds that has to pass between two consecutive runs of governor computations default: