What do you mean by "get recursive functions?" Call graph shows recursive functions in the graphical user interface. I don't think it displays anything in the command line output.
Sampling, because it has not knowledge of calling sequences, cannot display any information about recursive functions.
Thank you at first. It is right that Callgraph can give recursive functions. I should use vtl a1::r1 -gui to get the information of recursive functions. Can I use command line to know what functions are recursive functions? It will be convenient if VTune can do it.