ATTENTION! Manually changing the frequency of the CPU can lead to a hang, unstable operation and theoretically even damage to the device. Do everything at your own peril and risk! There are three main parameters that affect the power consumption of the processor, which can be changed: frequency, frequency control mode, voltage.
Frequency. All modern devices can dynamically control the frequency of its processor depending on its load, thereby adjusting its performance and power consumption. However, this may not always be correctly and optimally, in consequence of which the device will not have an economical energy consumption. In this case, when there is no active application, the screen is off, CPU frequency is reduced to a minimum value, prescribed in the Core EEPROM usually is 15-30% of the maximum frequency. In a properly optimized device, with an average daily load most of the time the processor will run it at minimum speed. Accordingly evaluate optimization of power consumption processor device can be looked processor performance statistics on a given frequency. To do this, open the app
Android System Info,, select the tab
System and item
CPU .
If there you see that most of the time the processor is running at maximum frequency, then there is a problem with optimization. In this case, first of all, you need to look at the graphics of the CPU usage in the monitoring programs, SystemPanel. If the processor does not load any application, due to which its frequency rises, then the regular frequency control mode does not work correctly.
To fix the situation set
В® SetCPU, with which you can not only set the operating frequency of the processor (or specify the operating frequency range), but also create frequency profiles that are activated by an event (application launch, charge reduction, screen off, time), that is, optimize the frequency control process for themselves.
For example, the frequency of the working mode can be set not more than 1000-1200 MHz; Event "screen off" and "charge is below 15%," the maximum frequency is limited to half the operating frequency, and minimum - set to minimum; set profiles for frequently used applications with the limitation of their maximum operating frequency of the value at which you saved comfort for the responsiveness of the interface (the games may be sufficient 800 MHz, and for watching movies and listening to music 500 MHz). This approach can save up to 50% charge sacrificial processor.
- Manual reduction of the maximum frequency by only 10-15% will have little effect on the increase in battery life, I advise you to reduce the frequency in normal mode by at least 25%.
- Note that the more economical the CPU operation mode (and, in fact, the lower the average frequency of its operation), the less responsive the interface may become and the lower the overall speed of the device. Test different modes of operation and select the most convenient for you in terms of the ratio of usability / economy.
Modes control the frequency of the processor. These modes (algorithms) determine how the processor frequency will vary, within what limits and how quickly, depending on the processor load, its duration, etc. The frequency control modes and the frequency change step are embedded in the Core and their set for different firmware may differ.
In most cores, there are 5 modes of CPU:
ondemand- step-by-step increase in the frequency of the CPU, depending on the load. The general meaning of the principle of operation is that every 20–200 ms the load is measured on cpu, total or by the user, and if the load at the current frequency is more than 95%, the frequency increases, if less than 20%, the frequency decreases by 1 step. The frequency of measurement,% transition load and the rest for all modes is set when compiling the kernel.
hotplug- based on ondemand, on multi-core devices disables unused kernels into idle time. Detailed description
here.
conservative- the same as ondemand, but the load for switching the processor frequency up or down is less - usually 20%. For example: 100-200-400-800-1000 MHz is available, we work at 200 MHz, the load has increased by 30%, we are switching to 400 Mhz.
performance- max available frequency, max performance.
powersave- minimum performance, maximum battery.
userspace- operates at user-defined frequencies.
On modern multi-core devices, it is most preferable to use the mode
hotplug, or
ondemandif the first one is missing. If we are talking about extreme energy saving, then suitable modes
powersaveand
userspace(with manual frequency setting).
You can choose the appropriate mode of operation for your processor in the same
В® SetCPU .
- Additional modes may be present in modified kernels:
Interactive- interactive mode, chases the frequency of the CPU in real time, almost always at full performance.
Smartass- mode based on Interactive. It features a faster decrease in frequency in idle time, and also lowers the frequency to a minimum when the screen is off.
X versions of Ondemand, Smartass, Interactive- these modes are based on the original modes + during sleep, the Conservative mode is set.
- I have a processor on1000 MHz I use the following settings:
- normal mode100-800 MHz (ondemand). Subjectively, this increases the operating time by about 15-20% .;
- viewing of the movie (at a long trip for example)100-400 MHz (ondemand). While watching movies at the same time increased by 30-40%.
In all modes, any "freezes" of the device was not observed.
Reducing the voltage of the processor (undervolting).