基于类型预测的甚块预测器

高性能的甚块预测器是保证EDGE体系结构性能的关键手段.为研究性能更好的甚块预测器,文中通过仿真实验发现甚块的出口类型独立于甚块的出口个数和甚块的动态执行结果而存在.以此为据,提出了基于类型预测的甚块预测器.该预测器摈弃了甚块出口号,直接对甚块出口类型进行预测.随后,根据对甚块出口类型可预测性的分析,通过实验证明甚块出口类型与历史和路径信息相关.仿真结果显示,与经典的基于出口预测的甚块预测器相比,文中提出的基于类型预测的甚块预测器能够将每千条指令误预测次数平均降低约10％.

Type-Only Hyperblock Predictor

Since EDGE architecture is hyperblock-based,high performance hyperblock predictors are crucial to guarantee promising performance of EDGE.Based on the analysis of hyperblocks’ exit types,we find that the exit type of a hyperblock is independent on the exit ID,motivating us to propose a type-only hyperblock predictor that predicts exit types without exit ID.Analysis of the predictability of exit types for hyperblocks proves that exit types are correlated to histories and/or paths,permitting us to incorporate aggressive prediction techniques into type-only hyperblock predictors to harvest better performance.Compared with conventional exit-based hyperblock predictors,experiments show that MPKI(Mispredicts Per Kilo Instructions) of our proposal is able to outperform by 10%.