Performance Measurement of Interpreted Programs

In an interpreted execution there is an interdependence between the interpreter's execution and the interpreted application's execution; the implementation of the interpreter determines how the application is executed, and the application triggers certain activities in the interpreter. We present a representational model for describing performance data from an interpreted execution that explicitly represents the interaction between the interpreter and the application in terms of both the interpreter and application developer's view of the execution. We present results of a prototype implementation of a performance tool for interpreted Java programs that is based on our model. Our prototype uses two techniques, dynamic instrumentation and transformational instrumentation, to measure Java programs starting with unmodi ed Java .class les and an unmodi ed Java virtual machine. We use performance data from our tool to tune a Java program, and as a result, improve its performance by more than a factor of three.