What does Busy%: in /sys/devices/system/cpu/cpuX/core_ctl/global_state file in android kernel means?

Question

Here is the snippet of the file "/sys/devices/system/cpu/cpuX/core_ctl/global_state"

    CPU0
    CPU: 0
    Online: 1
    Isolated: 0
    First CPU: 0
    Busy%: 0
    Is busy: 0
    Not preferred: 0
    Nr running: 0
    Active CPUs: 2
    Need CPUs: 2
    Nr isolated CPUs: 2
    Boost: 0

    What do the Busy% indicate can anyone explain?
    Is the busy% accurate?

Answer 1

The "Busy%" value in the /sys/devices/system/cpu/cpuX/core_ctl/global_state file on an Android kernel represents the percentage of time that the CPU core represented by "cpuX" has spent executing instructions during a given sampling period. It is used to determine the workload on a specific CPU core and can be used to make decisions about how to allocate resources on the device.

To determine the workload of a specific core using the "Busy%" field in /sys/devices/system/cpu/cpuX/core_ctl/global_state file, you can:

1. Read the value of the "Busy%" field for the specific core (X) in question.
2. Compare the value to the values for other cores to see if the workload is distributed evenly among the cores, or if one core is being used more heavily than the others.
3. If one core has a consistently higher value, it indicates that this core is handling a higher workload compared to the others.

Keep in mind that this method provides a general indication of the workload and should be used in conjunction with other tools and methods to get a complete picture of the performance of the system.