Microarchitectural Design Space Exploration Using an Architecture-Centric Approach

The microarchitectural design space of a new processor is too large for an architect to evaluate in its entirety. Even with the use of statistical simulation, evaluation of a single configuration can take excessive time due to the need to run a set of benchmarks with realistic workloads. This paper proposes a novel machine learning model that can quickly and accurately predict the performance and energy consumption of any set of programs on any microarchitectural configuration. This architecture-centric approach uses prior knowledge from off-line training and applies it across benchmarks. This allows our model to pre- dict the performance of any new program across the entire microarchitecture configuration space with just 32 further simulations. We compare our approach to a state-of-the-art program- specific predictor and show that we significantly reduce pre- diction error. We reduce the average error when predicting performance from 24% to just 7% and increase the cor- relation coefficient from 0.55 to 0.95. We then show that this predictor can be used to guide the search of the design space, selecting the best configuration for energy-delay in just 3 further simulations, reducing it to 0.85. We also eval- uate the cost of off-line learning and show that we can still achieve a high level of accuracy when using just 5 bench- marks to train. Finally, we analyse our design space and show how different microarchitectural parameters can af- fect the cycles, energy and energy-delay of the architectural configurations.