一种新的Java存储模型L-JMM

Java存储模型是Java语言和Java虚拟机研究中的核心关键部分,目前Java语言规范中的存储模型不能保证Java技术所必需的语义特性,而且不利于Java虚拟机的性能优化.提出了一种新的Java存储模型,该模型取消了规范中Java存储模型中对存储密致性的要求,保证了Location一致性;同时根据Java语义的要求,对Java语言中不同类型的变量详细规定了多线程存储操作的行为规则.该模型不仅能保证Java程序的正确性,同时能有效提高Java程序的运行效率.最后通过仿真实验验证了该存储模型的关键特性.

A New Java Memory Model L-JMM

Java memory model (JMM) is an important topic in Java language and Java virtual machine (JVM) design. But the memory model in Java specification can't guarantee the safely running of Java multithread code. It needs memory coherence, which imposes constraints that prohibit JVM implementation optimization. To fix the problem of Java memory model in Java specification, a new Java memory model, L-JMM, is proposed, which is based on location consistency. This model extends the location consistency to adapt the features of Java technology. It also defines the rule of Java multithread memory operation, including ordinary variable rule, volatile variable rule, final variable rule and synchronization rule. It is proved that this memory model has the same property as location consistency. It can guarantee the correctness for Java multithread code. It can also improve the performance of Java virtual machine. Finally, the simulation of this memory model in the simulator MMS verifies that the new model boasts a better performance than the Java specification memory model does.