Fail to open /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

[edisonchan]

sudo ./ftalat 3800 4700
Fail to open /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu1/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu2/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu3/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu4/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu5/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu6/cpufreq/scaling_available_frequencies
Fail to open /sys/devices/system/cpu/cpu7/cpufreq/scaling_available_frequencies

CPU: AMD Ryzen 7 5800X
OS: Ubuntu 22.04.3 LTS (GNU/Linux 6.4.10-060410-generic x86_64)

How can I fix this problem?

ls /sys/devices/system/cpu/cpu0/cpufreq
affected_cpus amd_pstate_lowest_nonlinear_freq cpuinfo_max_freq cpuinfo_transition_latency scaling_available_governors scaling_driver scaling_max_freq scaling_setspeed
amd_pstate_highest_perf amd_pstate_max_freq cpuinfo_min_freq related_cpus scaling_cur_freq scaling_governor scaling_min_freq

[edisonchan]

I know what happen.
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencie is only available with acpi-cpufreq driver but not available with amd pstate driver.

Why use /sys/devices/system/cpu/cpu7/cpufreq/scaling_available_frequencies in this program? The userspace cpufreq governors allow user to set freq.