The performance of Java has been tremendously improved by the advance of the compilation technology. However, debugging a dynamic compiler is much harder than a static compiler. Recompiling the problematic method again to produce a diagnostic output does not necessarily work because the compilation of a method depends on the runtime information at the time of compilation.
In this paper, we propose a new approach, called replay JIT compilation, to reproduce the same compilation process remotely using two compilers: the state-saving compiler saves all the input to the JIT compiler in the production environment, and the replaying compiler reproduces the same compilation process later. We reduced the overhead to save the input by using the system dump and categorizing the input based on the constancy. In our preliminary experiment, the overhead of running the state-saving compiler was negligible, and the size of the additional memory area needed for saving input was only 10% of the compiler-generated code.
By: Kazunori Ogata, Tamiya Onodera, Kiyokuni Kawachiya, Hideaki Komatsu, Toshio Nakatani
Published in: RT0641 in 2007
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