Using annotations to reduce dynamic optimization time

Dynamic compilation and optimization are widely used in heterogenous comput ing environments, in which an intermediate form of the code is compiled to native code during execution. An important tradeoff exists between the amou nt of time spent dynamically optimizing the program and the running time of the program. The time to perform dynamic optimizations can cause significa nt delays during execution and also prohibit performance gains that result from more complex optimization. In this research, we present an annotation framework that substantially red uces compilation overhead of Java programs. Annotations consist of analysis information collected off-line and are incorporated into Java programs. Th e annotations are then used by dynamic compilers to guide optimization. The annotations we present reduce compilation overhead incurred at all stages of compilation and optimization as well as enable complex optimizations to be performed dynamically. On average, our annotation optimizations reduce o ptimized compilation overhead by 78% and enable speedups of 7% on average f or the programs examined.