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Rockpi4/hardware/cpu

< Rockpi4‎ | hardware
Revision as of 10:30, 13 October 2021 by Jack-ma (Talk | contribs)

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    ROCK Pi 4 >  Hardware >  CPU

RK3399 has 6 CPU core, 2 big core A72, 4 little core A53. In Linux, CPU0 to CPU3 are little core, CPU5&6 are big cores.

check cpu[0-3] supported frequency

   # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
   408000 600000 816000 1008000 1200000 1416000

check cpu[4-5] supported frequency

   # cat /sys/devices/system/cpu/cpu5/cpufreq/scaling_available_frequencies
   408000 600000 816000 1008000 1200000 1416000 1608000 1800000

check cpu[0-3] current frequency

   # cat /sys/devices/system/cpu/cpu[0123]/cpufreq/cpuinfo_cur_freq
   1416000
   1416000
   1416000
   1416000

set cpu[4-5] max frequency

   # echo 1008000 > /sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq
   # echo 1008000 > /sys/devices/system/cpu/cpu5/cpufreq/scaling_max_freq

turn off the big cores

   # echo 0 > /sys/devices/system/cpu/cpu4/online
   # echo 0 > /sys/devices/system/cpu/cpu5/online