Search notes:

/sys/kernel/tracing

scripts/tracing/draw_functrace.py has the following example:

# mount -t tracefs nodev /sys/kernel/tracing
# echo function > /sys/kernel/tracing/current_tracer
$ cat /sys/kernel/tracing/trace_pipe > ~/raw_trace_func

Wait some times but not too much, the script is a bit slow.

Break the pipe (Ctrl + Z)

$ scripts/tracing/draw_functrace.py < ~/raw_trace_func > draw_functrace

Apparently, CONFIG_FUNCTION_TRACER needs to be set when compiling the kernel.

/sys/kernel/tracing

See also