A microcode-based environment for noninvasive performance analysis
S. W. Melvin, Yale N. Patt · 1986
We have developed an environment which allows us to collect data for performance analysis by modifying the microcode of a VAX 8600. This use of microprogramming permits data to be collected with minimal system perturbation (i.e. the data is almost as good as that obtained with a hardware monitor) but at the cost and with the ease of use of a software simulator. In this paper we describe the environment that we have developed and present two examples of its use. The first example, procedure call instrumentation, illustrates a technique for gathering data on how certain architectural features are used. The second example, instruction tracing, illustrates a technique for collecting data that can then be used in trace—driven simulation.