Branch History Matching: Branch Predictor Warmup for Sampled Simulation

Computer architects and designers rely heavily on simulation. The downside of simulation is that it is very time-consuming — simulating an industry-standard benchmark on today’s fastest machines and simulators takes several weeks. A practical solution to the simulation problem is sampling. Sampled simulation selects a number of sampling units out of a complete program execution and only simulates those sampling units in detail. An important problem with sampling however is the microarchitecture state at the beginning of each sampling unit. Large hardware structures such as caches and branch predictors suffer most from unknown hardware state. Although a great body of work exists on cache state warmup, very little work has been done on branch predictor warmup. This paper proposes Branch History Matching (BHM) for accurate branch predictor warmup during sampled simulation. The idea is to build a distribution for each sampling unit of how far one needs to go in the pre-sampling unit i...

• Type: Conference
• Year: 2007
• Where: HIPEAC
• Authors: Simon Kluyskens, Lieven Eeckhout
• Keywords: Branch Predictor, Branch Predictor Warmup, HIPEAC 2007, Sampling Unit, System Software