CSR---SMA: Validating Architectural Simulators Using Non-Linear Dynamics Techniques

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

This project strives to improve the state-of-the-art in architectural simulators in two ways: (i) by enabling users to determine if an architectural simulator correctly models the key aspects of a real hardware system; and (ii) by helping simulator implementors to identify weaknesses in their simulators. This problem is critical because much architectural research today uses simulations; if the simulators are not accurate then the results from the simulator may be misleading. Prior work validates simulators by using aggregate metrics (e.g., do the simulator and the real hardware execute a program in a similar number of total cycles?). This validation does not consider whether or not the simulator and the hardware exhibit similar time-varying behavior. A key innovation of this project is that it embraces techniques from the field of non-linear dynamics. These techniques are well suited for computer systems for two reasons. First, computer systems are non-linear at all levels (e.g., the cost of a cache miss is not fixed and instead depends on many factors) and thus linear techniques will be of only limited use. Second, many aspects of computer systems are unknown (e.g., the hardware manufacturer may not reveal the full specifications of the hardware) or unmeasurable (e.g., it may not be possible to measure how often a particular event occurs deep down in the hardware). Non-linear dynamics techniques are specifically designed to deal with such missing information.