(Georgia Institute of Technology, 2023-08-25)
Lavin, Patrick
As computer systems grow larger and more complex, it takes more time to simulate them in detail. Researchers interested in simulating large systems must choose between simpler, less-accurate models or simulating smaller portions of their benchmarks, both of which can be highly manual, offline approaches that require time-consuming analysis by experts. Multifidelity simulation aims to lessen this burden by adapting the fidelity of a simulation to the complexity of the behavior being simulated.
Multifidelity simulation refers to a simulation that can utilize multiple models for the same phenomena at different levels of fidelity. We borrow the phrase from the simulation of physical systems where scientists may have models with more or fewer terms, or may resolve their models on smaller or larger grid sizes, depending on the nature of the behavior at any point or time in the simulation. We have taken those ideas and applied them to computer architecture simulation.
In this dissertation, we will present our novel multifidelity computer architecture simulation algorithm and implement it in two separate models: one for the cache and one for the entire memory system. Our cache model is able to automatically train and choose between low-fidelity models to adapt to the complexity of the modeled behavior online. The second model, the memory system, refines upon the ideas developed to create the first. We use statistical techniques to choose data that is used to create the low-fidelity models and implement this work as reusable components within a widely-used simulator, SST. This model achieves up to 2x speedup with only 1-5% mean error in the instructions per cycle.