The approach taken by
rr is entirely different from the one I used in ELFE. From the web page,
rr records program execution at the machine level, with the intent to allow later deterministic replay of a recorded session within
gdb. I find this idea extremely interesting.
It does not seem to be packaged in Fedora 25 yet. At least,
dnf install rr gives nothing. But I think I’m going to spend some time installing and testing it soon. In the meantime, I just share its existence.