Enhancing Java processor performance with smart dynamic folding

Abstract

The Java processor is suitable for Internet appliances or embedded controllers due to its speed and low memory requirement. However, its performance is severely limited by true data dependence. In this work, we present a smart and dynamic stack operations folding - POC model-based folding. The stack instructions are classified into P,O, and C three types. The folding algorithm can automatically determine the folding relations among all the instructions based on the type and folding attributes of each instruction. The proposed algorithm has no requirement to match different patterns. A typical folding mechanism design based on this model is then introduced. Also, the performance of various folding methods based on the POC model is evaluated. Simulation data indicate that the 4-foldable method eliminates 84% of all stack operations. Furthermore, the 2-, 3-, and 4-foldable methods accelerate the overall program by 1.22, 1.32 and 1.34, respectively, as compared to a Java processor without folding.