Intel sponsors the green card of their employees.

Just saying'.

The same way you tax more people earning more money ?

DTrace has been doing this kind of things, in a safe and usable-in-production way, for years (and the code, while not trivial, is usually pretty cool to read): https://github.com/joyent/illumos-joyent/blob/master/usr/src...

For userspace probes DTrace uses INT3 AFAIK. Taking a signal each time a probe gets hit can be high overhead for certain usages though (like low overhead profiling as opposed to intrusive debugging).