CPU Frequencies - 2020.2 English

Versal ACAP System Software Developers Guide (UG1304)

Document ID
UG1304
Release Date
2020-11-24
Version
2020.2 English

Enable this feature to permit the CPU cores to switch between different operation clock frequencies.

Required Kernel Configurations
  • CPU Frequency scaling
    • [*] CPU Frequency scaling
    • Default CPUFreq governor
      • Userspace
  • CPU Power Management
    • [*] CPU Frequency scaling
    • Default CPUFreq governor
      • Userspace
      • <*> Generic DT based cpufreq driver
Example Commands
The following are some commands related to CPU frequency scaling:
  • Look up the available CPU speeds:
    cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cpu_freq
  • Select the 'userspace' governor for CPU frequency control:
    echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
  • Look up the current CPU speed (same for all cores):
    cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cpu_freq
  • Change the CPU speed (same for all cores):
    echo <freq> > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

For details on adding and changing CPU frequencies, see the Linux kernel documentation on Generic Operating Points.