Cache locking optimization in java virtual machine

摘要

Cache plays an important role in multilevel storage system. It can greatly reduce the memory access latency. So the cache hit rate has a significant impact on the performance of the application. Many processors provide cache locking mechanism, which can lock the certain lines in cache. It enables an application to affect the cache replacement decisions under software control. This paper presents a novel method, which uses cache locking mechanism to reduce the run-time of java virtual machine (JVM). JVM often uses just-in-time compiler (JIT) to improve the performance. JIT compiles the method that has been invoked certain times, and then JVM executes the compiled method when invoking this method the next time. This paper analyzes the calling situation of the compiled method in JVM, and then proposes a heuristic approach to lock the compiled method in cache for an appropriate period. It can reduce cache miss rate when JVM executes the compiled method. The algorithm has been implemented in HotSpot based on Loongson-3A. Also, it can be implemented in other run-time systems. Experiment results show that the cache locking heuristic algorithm averagely reduces the cache miss rate by 8.5%, and improves the performance by 4% on the benchmark SPECjvm2008.