I have 4 cores cpu on my device, but each time I use this command line to genetrate a systrace file :

python C:/Users/BJI/AppData/Local/Android/Sdk/platform-tools/systrace/systrace.py freq idle -o C:/Users/BJI/Desktop/systrace

I get a different number of cores (2 or sometimes 1 core cpu), is it only the number of active cores ?

1 Answer 1


you can check how many cpu<?> under /sys/devices/system/cpu/

for example, If CPU has two cores, there should be


  • I have 4 cores, even in my power_profile.xml I get 4 cores cpu, but it is different for the systrace output, sometimes I get 2, other times I get 1 core ...
    – Sarra
    Apr 30, 2021 at 0:56
  • if there is no trace event happened on that core, the systrace won't show the cpu core. there is a very common power saving strategy when you turn screen off, the system will unplug some cores to save power; BTW, Is there some IM groups we can chat with each others to share experience with android. for example, port android to a new arm device?
    – Kevin Ding
    Apr 30, 2021 at 1:38
  • thank you for your help @kevin , I don't know if this helps but here [ community.arm.com/f ] is arm community where you can find many forums
    – Sarra
    Apr 30, 2021 at 2:45

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