There are times when developers and system administrators need to diagnose
problems in running code. The program to be examined can be a user-space
process, the kernel, or both. Two of the major tools available on Linux to
perform this sort of analysis are
SystemTap and
bpftrace. SystemTap has been available
since 2005, while bpftrace is a more recent contender that, to some,
may appear to
have made SystemTap obsolete. However, SystemTap is still the preferred
tool for
some real-world use cases.

Source: LWN.net – [$] Comparing SystemTap and bpftrace