【Android 性能引擎】硬件提频

动态修改硬件频率，提高机器性能。

CPU提频

cpufreq框架图：

cpufreq framework会通过cpufreq core、cpufreq governors、cpufreq stats等模块，以sysfs的形式，向用户空间提供cpu frequency的查询、控制等接口。

各字段解释如下：

cpuinfo_cur_freq: The current operating frequency of the cpu

cpuinfo_max_freq: This file specifies the maximum operating frequency at which the processor can run (unit: kilohertz)

cpuinfo_min_freq: This file specifies the minimum operating frequency at which the processor can run (unit: kilohertz)

cpuinfo_transition_latency: This file defines the time required for the processor to switch between two different frequencies (unit: nanoseconds)

scaling_available_frequencies: list of all supported main frequencies (unit: kilohertz)

scaling_available_governors: This file shows all cpufreq governor types supported in the current kernel

scaling_cur_freq: The current CPU operating frequency determined by the governor and cpufreq cores. This frequency is the main frequency that the kernel thinks the CPU is currently running

scaling_driver: This file shows which cpufreq driver the CPU is using

scaling_governor: Through the echo command, the governor type of the current processor can be changed

scaling_max_freq: Display the upper and lower limits of the current policy (unit: kilohertz). It should be noted that when changing the cpu policy, you need to set scaling_max_freq first, and then scaling_min_freq

scaling_setspeed: If the user selects the “userspace” governor, then the main frequency of the cpu can be set to a specified value.

可修改调频器提高频率，例：echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor；调频器可选项和CPU厂商有关。