Simulation Differences Between Academia and Industry: A Branch Prediction Case Study

Computer architecture research in academia and industry is heavily reliant on simulation studies. While microprocessor companies have the resources to develop highly detailed simulation infrastructures that they correlate against their own silicon, academic researchers tend to use free, widely available simulators. The differences in instruction set architectures, operating systems, simulator models and benchmarks create disconnect between academic and industrial research studies. This paper presents a comparative study to find correlations and differences between the same microarchitecture studies conducted in two different frameworks. Due to the limited availability of industrial simulation frameworks, this research is limited to a case study of branch predictors. Encouragingly, our simulations indicate that several recently proposed branch predictors behave similarly in both environments when evaluated with the SPEC CPU benchmark suite. Unfortunately, we also present results that show that conclusions drawn from studies based on SPEC CPU do not necessarily hold when other applications are considered