Slight off-topic and tangent: I am looking into writing some basic compiler(s) but I really want to emphasize micro-optimizations, maybe even the stochastic on

Slight off-topic and tangent: I am looking into writing some basic compiler(s) but I really want to emphasize micro-optimizations, maybe even the stochastic ones -- don't ask why, it's just an obsession. Question: is there an Arduino-like hardware that allows FULL visibility into the efficiency of every piece of code ran on it? On my first job, 20 years ago, there was a team working on embedded boards that maybe did something similar. But again, I am looking for a piece of hardware -- and a software stack for it -- where you say "here's this chunk of assembly / machine code, run it and give me detailed statistics which instruction got ran the most times, which one took the longest time" etc.? Is there something like that out there?