Intel Corporation

Alice Kwong

Michael Lai

Julie Wang

Kevin J Smith

Hugh R Kenner

William A Savage

James W O'Neill

A method of optimizing program code performance is disclosed. Applications written in the Java language can execute slowly. To speed up the execution time of a Java application certain slower executing methods within the application can be written in native code. When the slower executing methods are written in native code some of the advantages, such as automatic garbage collection, of the Java language are lost. Further, the resultant interface function calls between the Java methods and the native methods can result in inefficient code. The method optimizes programs written using both Java methods and native methods, i.e. mixed mode code, by analyzing a set of interface function calls from native methods to a Java Virtual Machine. Then selects a plurality of the interface function calls to either eliminate or move within the program code by analyzing either the bytecode and the intermediate language, or both, for either inefficient code constructs or inefficient code containing native interface function calls to perform garbage collection.

Optimization of garbage collection code in the context of raw native interface function calls in the java programming language

Compilers are tools that generate efficient mappings from programs to machines A Java &ldquo;Just In Time&rdquo; runs as part of an application, and as such, it must be fast and efficient in its use of memory. To achieve good performance and further optimize code generation, the present invention introduces a method for optimizing Java performance using precompiled code. The method of the present invention first monitors the performance of program code during program execution. Then a list of program functions for possible native code compilation is created. The list may be created based upon static and dynamic analysis of the computer program. A plurality of program functions from said list of program functions is selected for optimization and native compilation. The selected program functions are precompiled into native program functions. The present invention also allows the precompiled native code reverted so that a user could explore the performance tuning until satisfactory.

Method for optimizing Java performance using precompiled code

An improved register allocator, an improved instruction scheduler, an instruction combiner, and an improved loop unroller is provided to the code generator of a compiler of a computer system. Both the improved instruction scheduler and the improved loop unroller support a 'preliminary' and a 'final' mode of operation. Upon invocation, the improved register allocator determines and prioritizes regions of the program being compiled. Next, the improved register allocator, in cooperation with the improved instruction scheduler, the instruction combiner, and the improved loop unroller, determines the optimal partitioning for global and local registers for each region. Then, the improved register allocator allocates registers to each region based on the determined number of global registers for the region. After allocating registers for each region, the improved register allocator merges the regions together. The improved loop unroller and the improved instruction scheduler are then invoked successively in 'final' mode to unroll the various loops and schedule the instructions being generated.

Growing community of inventors

Los Altos, CA, United States of America

Alice Kwong