Energy Optimization Using Object Co-Location in Java

With the paradigm shift in computer systems towards ubiquitous computing, energy, together with performance, has become an important parameter to measure e ciency. Java is increasingly becoming the programming language of choice for applications expected to run in embedded and mobile environments. Java's platform independence and security features serve the needs of these environments very well, which expect the same application to run in a variety of environments in a secure manner. The devices used in these environments, for example hand-held computers, have a limited battery life. The needs to increase the period between recharging and decrease the cooling costs provide the incentive to use energy as a performance parameter. This paper presents object co-location, an optimization method for Java applications. Object co-location exploits the temporal locality in heap references, to achieve better cache performance. This reduces the cache miss rate of programs, and subsequent reduction in memory energy consumption is observed due to fewer main memory accesses.