Definition of DVFS
The full name of the text is: Dynamic voltage and frequency scaling, the abbreviation is DVFS; Chinese is generally translated as dynamic voltage and frequency scaling
CPUs above armv8, such as CORTEX-A37 53 55 and other V8 architecture CPUs, have a relatively high main frequency. If it is always high, it will waste power, especially for battery devices such as mobile phones and tablets.
The current Rockchip, Allwinner, and AMLOGIC SOCs all have this function
DVFS system process:
Collect signals related to system load and calculate current system load.
Based on the current load on the system, predict the performance that the system will need in the next time period.
Convert the predicted performance to the desired frequency, thereby adjusting the chip's clock settings. 4. Calculate the corresponding voltage according to the new frequency. Notify the power management module to adjust the voltage to the CPU.
In addition, when adjusting frequency and voltage, pay special attention to the order of adjustment.
When the frequency is adjusted from high to low, the frequency should be lowered first, and then the voltage should be lowered; on the contrary, when the frequency is increased, the voltage should be increased first, and then the frequency should be increased.
Although not many do DVFS, because many of them are stumped by prediction algorithms, but the author believes that with the advancement of prediction algorithms, DVFS technology will be widely used because it can save a lot of energy. Energy saving is often the first requirement for many portable devices.
Question: Is it possible to only adjust the frequency and not adjust the voltage?
Answer: Yes, especially during the debugging phase.
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Original link: https://blog.csdn.net/xushx_bigbear/article/details/125794558