基于反馈的JCVM指令预调度方案

Feedback-based JCVM Instruction Prescheduling Scheme

卡内应用执行效率较低是制约Java Card发展的瓶颈。为此,研究Java Card虚拟机(JCVM)解释器的运行原理,针对其执行架构提出一种基于反馈的JCVM指令预调度方案。通过收集反馈应用的运行指令流统计信息,设计解释器加权控制流图(WCFG),利用基于WCFG的代码编排技术实现解释器的指令预调度。在目标体系架构中,将热点指令处理函数的布局按照反馈应用的统计信息进行重新编排。实验结果表明,该方案可使JCVM解释器的应用执行效率提高15.29%,并且不依赖额外系统资源,对基于解释器架构且资源受限的嵌入式设备性能优化具有指导意义。

The Low efficiency of on-card applet execution is a bottleneck restricting the development of the Java Card, so this paper researches the operating .principle of Java Card Virtual Machine（JCVM）, and proposes a feedback-based JCVM instruction prescheduling scheme to optimize the executable architecture of Java Card. It designs a concept of Weighted Control Flow Graph（WCFG） by collecting run command flow statistical information of feedback applications, and then a code arrangement technology based on WCFG is proposed to realize the pre-scheduling of interpreter. In the target system architecture, it reorders the hot instruction handler functions according to the statistical infurmation of feedback applications. Experimental results show that after optimization of the scheme, the efficiency of the interpreter increases 15.29%, and it does not rely on additional system resources, so it is helpful to the optimization of embedded device based on interpreter architecture and which is resource-constrained.