# Dynamic voltage and frequency scaling

Dynamic voltage and frequency scaling (DVFS) management is a technique
used to switch the CPU core frequency based on load requirement. This
technique helps to balance the power, performance, and thermal behavior
of the device.

![../../_images/Dynamic_voltage.png](data:image/png;base64,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)

**Figure : DVFS workflow**

For more information on DVFS, see [index:
kernel/git/torvalds/linux.git](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/cpu-freq?h=v6.6).

For example, if the available CPU frequencies are 1 GHz, 1.5 GHz, and 2
GHz, and the application must run at 1 GHz, then the maximum frequency of
the CPU should be maintained at 1 GHz. This mechanism ensures right
utilization of the CPU frequency and its voltage, thereby optimizing CPU
power to maintain high performance.

## CPU frequency scaling tunables

The following table lists the commands used to tune CPU frequency for
balanced power and performance:

Table : Commands to tune CPU frequency

| Commands | Explanation |
| --- | --- |
| cat /sys/devices/system/cpu/cpufreq/policy<x>/scaling_cur_freq<br>    Copy to clipboard | Reads the existing CPU frequency |
| cat /sys/devices/system/cpu/cpufreq/policy<x>/scaling_available_frequencies<br>    Copy to clipboard | Reads the supported frequencies |
| cat /sys/devices/system/cpu/cpufreq/policy<x>/scaling_min_freq<br>    Copy to clipboard | Reads the minimum supported CPU frequency |
| echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy<x>/scaling_min_freq<br>    Copy to clipboard | <ul class="simple"><br><li><p>Sets the minimum CPU frequency</p></li><br><li><p>Overwrites the existing CPU minimum frequency</p></li><br><li><p>Sets any frequency from <code class="docutils literal notranslate"><span class="pre">scaling_available_frequencies</span></code></p></li><br></ul> |
| cat /sys/devices/system/cpu/cpufreq/policy<x>/scaling_max_freq<br>    Copy to clipboard | Reads the maximum supported CPU frequency |
| echo <cpu freq in KHz> > /sys/devices/system/cpu/cpufreq/policy<x>/scaling_max_freq<br>    Copy to clipboard | <ul class="simple"><br><li><p>Sets the maximum supported CPU frequency</p></li><br><li><p>Overwrites existing maximum CPU frequency</p></li><br><li><p>Sets any frequency from <code class="docutils literal notranslate"><span class="pre">scaling_available_frequencies</span></code></p></li><br></ul> |

Tab QCS6490/QCS5430
Tab QCS9075
Tab QCS8275

Note

`<x>` refers to 0, 4, 7.

- 0 is for the Silver cluster
- 4 is for the Gold cluster
- 7 is for the Prime cluster
- Unit for frequency is KHz

Note

`<x>` refers to 0, 4.

- 0 is for Cluster0
- 4 is for Cluster1
- Unit for frequency is KHz

Note

`<x>` refers to 0, 2, 4.

- 0 is for the Gold cluster
- 2 is for the Prime cluster
- 4 is for the Silver cluster
- Unit for frequency is KHz

Any modifications made through `SSH` commands revert to their default values upon device reset.

Last Published: Jan 26, 2025

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