You summed it up nicely, thanks. I kinda had LTTng and the other solutions in mind when I said there's many competing implementations, with varying degrees of f

You summed it up nicely, thanks. I kinda had LTTng and the other solutions in mind when I said there's many competing implementations, with varying degrees of functionality and maturity, and of course not all in mainline. As a user, it's a mess because for example Erlang/OTP has added LTTng support, which I expect to be born out of a user requirement based in an environment like SLES or RHEL. That doesn't make it universally practical on a random kernel. Then we have DTrace emulation in SystemTap, and I've heard it kinda works, but I don't know how many probes exist for it. If I want to trace on illumos or FreeBSD (NetBSD as well), there's just DTrace and I can share tracing code to some extent and the DTrace probes, say, in VMs have to be implemented once. Like you, I hope there will be a coherent solution, but I don't see it yet.