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Scaling drivers talk to the hardware. Maximum frequency the CPUs belonging to this policy are allowed to be running at in kHz. This is the frequency. For this reason, CPUFreq allows scaling drivers to bypass the governor layer and implement their own performance scaling algorithms. So if you have any we are going remove them now.

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Typically this is set to values of around ” or more. The ratio of the non-idle active time to the total CPU time is taken as an estimate of the load.

This is how much the frequency is allowed to change in one go. This has been merged into the acpi-cpufreq module in later kernels. You can switch to root and run the same commands cpfreq without the sudo sh -c ” ” if you like. The Linux Kernel 4.

CPU Performance Scaling — The Linux Kernel documentation

In some situations deterministic behavior is more important than performance or energy consumption or both and the ability to disable boosting while the system is running may be useful then. This keeps it up until the process is complete for all cores. Then when it bounces back it’s already scaled up from the last bounce.

The frequency boost mechanism may be either hardware-based or software-based. It returns the last frequency requested by the governor in kHz or can be written to in order to set a new frequency for the policy. Look at the output from lsmod above and use the modules names after the word “modprobe” below to see if you already have a module loaded. Typically, they are used along with algorithms to estimate the required CPU capacity, so as to decide which P-states to put the CPUs into.


The following Blackfin processors are supported by cpufreq: If the value in this file is 1, the frequency boost mechanism is enabled.

Reproducible results are important when running benchmarks.

HowTo/CpuFrequencyScaling – Debian Wiki

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. In some situations it is desirable or even necessary to run the program as clufreq as possible and then there is no reason to use any P-states different from the highest one i.

All of the frequency scaling will be done with kernel modules and not user space governors. Yours may be the same way. In that case, it only is necessary to restart the scaling governor so that it can take the new online Ad into account.

Some BIOS’s may not have an option for either. Some processors support a mechanism to raise the operating frequency of some cores in a multicore package aamd 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.


The default value of this attribute is 0 in ccpufreq case. However, that observation may not hold for performance scaling algorithms based on information provided by the hardware itself, for example through feedback registers, as that information is typically specific to the hardware interface it comes from and may not be easily represented in an abstract, platform-independent way.

Powersave governor – CPU runs at min frequency regardless of load.

The scaling driver may be registered before or after CPU registration. Typically, it is set to values of the order of 10 ms. If that is the case check your BIOS’s manual for more information.

It defines the basic framework in which the other components operate. In either case the name of the subdirectory containing the governor tunables is the name of the governor providing them.

acpi-cpufreq: Add support for modern AMD CPUs

You can go about setting these on reboot a few ways. There are some userspace programs that can be run to scale the processors frequency. This typically can happen through often not.

First you have to choose the governor you want to use. Of course, since the utilization of the system generally changes over time, that has to be done repeatedly on a regular basis.