Accurate Branch Prediction on Short Threads

Multi-core processors, with low communication costs and high availability of execution cores, will increase the use of execution and compilation models that use short threads to expose parallelism. Current branch predictors seek to incorporate large amounts of control flow history to maximize accuracy. However, when that history is absent the predictor fails to work as intended. Thus, modern predictors are almost useless for threads below a certain length. Using a Speculative MultiThreaded (SpMT) architecture as an example of a system which generates shorter threads, this work examines techniques to improve branch prediction accuracy when a new thread begins to execute on a different core.