Pid Target does not profile Sub-processes

[zz85]

Profiler doesn't seem to profile child-processes of pid if Perf event are attached to singular PID.

Perhaps the profiler needs to be attached to each child pid, or it might be easier to filter in ebpf, like https://github.com/iovisor/bcc/blob/c31a1ca305f787ba53e001ead45ebf65233a32cf/tools/profile.py#L184