I remember that! Worked at Intel's biggest chip customer (very early on). They asked us what we wanted in the next generation. Nobody said much, so I made a manifesto - bus data breakpoint interrupts, jump history fifo, and a timestamp counter and count-match interrupt register! It showed up in the next spec, but as a privileged instruction sadly. And at clock speed. I wanted it at a fixed frequency for I/O timing, and I wanted it for everybody - drivers, apps, kernel, everbody.