Mobile Smart Device Power Optimization Series-Foreword (shared by Nvidia Senior Project Division)

This is the first article from an original team member of the embedded Penguin Circle, the Nvidia Senior development project, Terry, who will launch a series of summary shares on the topic "Power optimization for mobile smart devices".

Terry has a great value in summarizing and sharing its experience of optimizing the power consumption of mobile devices in leading Nvidia multiple project development.

As smart mobile devices become more functional. The cpu/memory frequency is also getting higher. The resulting power problems are becoming more and more serious, how to prolong the phone's standby and use time has always been the problem that each handset manufacturer has to face. This topic will explain to you the current mainstream power optimization strategy and some useful optimization debugging methods, hoping to play a role.

Today the mainstream mobile CPU is 1-2ghz at its highest frequency. Higher frequency leads to higher power dissipation. So we don't need the CPU to work at the highest frequency at all times. Most of the time. The CPU is actually working in a light load state, depending on the system load, the CPU can work in multicore/single core. High frequency/low frequency, or switch between FCPU (for example, A57) and scpu (for example, A53). Assume a lighter load, for example, off-screen standby. The CPU is able to switch to LP0, resulting in CPU power consumption approaching 0. The above process involves the following techniques.

I. Mechanism of Linuxcpuquite

For multicore CPUs, executing the game requires all core online. Browse the Web Perhaps 1 cores is enough, how to evaluate the current need for a few core online? How to achieve CPU core hot plug?

Because this technology is unique to nvidia. deals with trade secrets. It is not possible to start writing. If you have a friend you need, please Google yourself.

Ii. mechanism of Linuxcpufreq

User scenarios are different. The demand for performance is also different. What frequency should the CPU perform? The frequency is low, the card is high, and the charge power is higher. If there is a sudden incident, how to increase the frequency of the frequency reduction to ensure that the system is smooth and just a lot of energy consumption? The following is a software system framework. Detailed explanations will be given later.

Iii. mechanism of Linuxcpuidle

Assume that the load is light. The system can enter a lower pstate (for example, LP0/SC7) and turn off the CPU. Memory, peripherals to reduce power consumption. How to achieve? How does the system wake up? Below is the software system framework, which will be explained in detail later.

Four, DVFS dynamic voltage frequency regulation

This people should not be unfamiliar, this is a real-time voltage frequency regulation technology, because of the requirements of CMOS, the CPU wants to run stably to higher frequency need higher voltage, and this voltage is related to the chip speedo and IDDQ and temperature, how to determine? Below is the software system framework, which will be explained in detail later.

Of course, optimization techniques are becoming more complex because of the increasing power requirements. Each vendor has its own unique technology. If you are interested, you are welcome to leave a message for your readers. or email me to discuss: [email protected], thank you.

This article provides an overview of the power optimization for mobile devices, which will be followed by an in-depth analysis of the principles and practices of each section. Please pay attention!

The original team of embedded Penguin Circle consists of Ali, Meizu, nvidia, godson, Ju Li, and other senior Project division. Hundred percent original, two articles per week. Share embedded, Linux, IoT, GPU, Android, self-driving and other technologies.

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Mobile Smart Device Power Optimization Series-Foreword (shared by Nvidia Senior Project Division)