I would like to write software that can reliably get the "relative physical time", with the highest resolution, and lowest overhead as possible.
By "relative physical time", I mean, for example, the actual amount of physical time that has passed in the physical world since the computer was turned on. It doesn't need to be relative to some external time system, calendar, or event.
While there is a plethora of information about this, I think it is a topic this is misunderstood by SW people (including myself), and thus, lot's of misinformation. Hopefully an electrical or computer engineer is better informed.
Do computers (ex. iPhones, game consoles, personal PC's) come equipped with hardware to do this? Or, are there trade offs that need to be made: (i.e. if we want high res + low overhead, use a time step counter (ex. RDTSC), but no longer "wall time").