Java Virtual Machine: the key for accurated memory prefetching

The popularity of the Java language is easily understandable analyzing the specific features of the language and the execution environment. However, there are still aspects of the Java execution environment that are not exploited. One of the most distinctive features of this platform is the knowledge that the Java Virtual Machine (JVM) has about the runtime characteristics of the applications. In this paper we show an example of how the JVM could use the applications runtime information to help the operating system in some tasks related to resources management, improving significantly the performance of the Java applications. In particular, we focus on the memory management and on the memory prefetching strategy. We show that it is possible to improve the performace from traditional prefetch approaches. In order to prove this idea we have designed and implemented a prototype to add memory prefetching into de JVM. This prototype achieves to overlap the time required to read the memory from disk with the computing time of the application, improving the final performance of the applications.