Emulation of systems makes it possible to combine the predictive power of simulation with the advantages of measurement carried under a real system workload. An emulator is a microprogrammed implementation of the basic hardware machine. It can be easily instrumented to collect performance statistics on the instruction set processor (ISP) level and support performance measurement of different configurations and software of the emulated system. This paper describes the monitoring capabilities of the Microprogrammable Multi-Processor (MMP), a powerful emulator system that serves as an experimental tool for evaluating computer systems. The measurement capabilities of the MMP on various system levels are described, as well as existing performance monitoring tools and their applications. Preliminary results contrasting the Gibson mix and measured instruction frequencies on the AN/GYK-12 computer in a TACFIRE system are given.