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On April 30th, I am holding my public PhD defense.

Title

Three Pitfalls in Java Performance Evaluation.

Abstract

Executing a Java application is a complex matter when looking at what happens under the hood. The virtual machine (VM) runs the operations and takes care of class loading, compiling and optimising code, and garbage collection. Due to the interaction going on between the VM and the application and the non-determinism (e.g., due to time-based sampling) within the VM, no two executions will ever behave exactly alike. Performance analysis in this context should not be underestimated. In this dissertation, we uncover three pitfalls that have not been taken into consideration prior to this research.

First, we show that one should not extrapolate performance results from one VM to another, and that small input sets do not necessarily yield behaviour that is representative for large(r) input sets. Second, we demonstrate that prevalent data analysis is falling short of the mark in many cases and can results in erroneous conclusions when making performance comparisons. We propose a rigorous statistical approach that deals with the problems posed by non-determinism. We also add rigour to one particular experimental design, namely, replay compilation.Finally, we illustrate that Java applications exhibit phase behaviour at the method level. We exploit this feature to allow a programmer to gain insight in the performance of his application by allowing him to locate bottlenecks and thus optimise his program by removing them.

Venue

As the examination is a public event, everybody can attend. I do ask that you drop a note, or leave a comment if you will be attending. Otherwise, you and several other people might find themselves without drinks at the reception afterward. The event takes place in the Jozef Plateauzaal of the Faculty of Engineering , J. Plateaustraat 22, 9000 Gent and it starts at 14:00.