Hybrid compilation and optimization for java-based digital TV platforms

Abstract

The Java-based software platform for interactive digital TV (DTV) is composed of the system/middleware class statically installed on the DTV set-top box and the xlet applications dynamically downloaded from the TV stations. The xlet application includes Java classes and image/text files. The xlets are executed only when the TV viewer initiates an interaction, even if the xlets have been completely downloaded. To achieve high performance on this dual-component, user-initiated system, existing just-in-time (JIT) compilation and optimization is not enough; instead, ahead-of-time and idle-time compilation and optimization are also needed, requiring a hybrid compilation and optimization environment. We constructed such a hybrid environment for a commercial DTV software platform and evaluated it using real, on-air xlet applications. Our experimental results show that the proposed hybrid environment can improve the DTV Java performance by more than three times, compared to the JIT-only environment, with little change to other DTV behavior.