A multinomial clustering model for fast simulation of computer architecture designs

Computer architects utilize simulation tools to evaluate the merits of a new design feature. The time needed to adequately evaluate the tradeoffs associated with adding any new feature has become a critical issue. Recent work has found that by identifying execution phases present in common workloads used in simulation studies, we can apply clustering algorithms to significantly reduce the amount of time needed to complete the simulation. Our goal in this paper is to demonstrate the value of this approach when applied to the set of industry-standard benchmarks most commonly used in computer architecture studies. We also look to improve upon prior work by applying more appropriate clustering algorithms to identify phases, and to further reduce simulation time.We find that the phase clustering in computer architecture simulation has many similarities to text clustering. In prior work on clustering techniques to reduce simulation time, K-means clustering was used to identify representative program phases. In this paper we apply a mixture of multinomials to the clustering problem and show its advantages over using K-means on simulation data. We have implemented these two clustering algorithms and evaluate how well they can characterize program behavior. By adopting a mixture of multinomials model, we find that we can maintain simulation result fidelity, while greatly reducing overall simulation time. We report results for a range of applications taken from the SPEC2000 benchmark suite.