On Void Linux, the /sys/kernel/tracing is empty, which means the ftrace control directory is not mounted automatically, so you need mount it manually:
# mount -t tracefs nodev /sys/kernel/tracing
# cd /sys/kernel/tracing
# ls
README free_buffer set_event trace_clock
available_events function_profile_enabled set_event_notrace_pid trace_marker
available_filter_functions hwlat_detector set_event_pid trace_marker_raw
......