Just-in-time optimizations for high-performance Java programs

✍ Scribed by Cierniak, Michał; Li, Wei

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 93 KB
• Volume: 9
• Category: Article
• ISSN: 1040-3108
• DOI: 10.1002/(sici)1096-9128(199711)9:11<1063::aid-cpe344>3.0.co;2-g

✦ Synopsis

Our previous experience with an off-line Java optimizer has shown that some traditional algorithms used in compilers are too slow for a JIT compiler. In this paper we propose and implement faster ways of performing analyses needed for our optimizations. For instance, we have replaced reaching definitions with constant values and loop induction variables with loopdefined variables. As a result, our JIT compiler, Briki, is very fast, so that its running time is negligible even when the data sets used with our benchmarks result in execution times of only a few seconds. The impact for the same benchmarks running on more realistic problem sizes would be even smaller.

Currently the speedups resulting from applying our optimizations are between 10% and 20%, but when the JIT compiler performs standard optimizations which are absent in the current version of the JIT compiler used by us, the speedups should be similar to the ones observed for Fortran programs -up to 50%.