Evaluation of multilevel memories

Proposed memory hierarchy technologies and configurations are usually evaluated by repeated running of "typical" jobs through simulated hierarchies while various parameters are adjusted. Simulation is too slow to be a tool for selecting among the choices in 1) technologies to be included, 2) implementation of each technology, and 3) management of data flow in the hierarchy. Four current hardware-managed hierarchies are described in a manner which parameterizes their design. The evaluation process is described in terms of address traces, hit ratios, and system cost performance. Stack processing is then described as a replacement for simulation that obtains hit-ratio data 1000 times faster than before. Finally, an example is given to illustrate how to select between two competing technologies, how to design the best hierarchy, and how to determine the information flow which optimizes the total cost performance of the system.