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Flow and time analysis of jitting methods Disclosure Number: IPCOM000013392D
Original Publication Date: 2000-Mar-01
Included in the Prior Art Database: 2003-Jun-18

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When analyzing the performance of a java virtual machine, it is nice to have a way to identify where time is spent performing what type of operations and on behalf of what types of processing. In particular, it is helpful to know what time is spent interpreting method(s), what time is spent executing the jitted method(s), and what time is spent jitting the method(s). This knowledge may be used to help determine when to jit a method and in determining how much time to spend jitting a method is warranted. Also, summary statistics, such as, the total time spent interpreting, executing jitted methods, and jitting methods for a specific run would be helpful in this determination. Please note that it is not sufficient to simply take the difference between the end time and the start time to identify the time spent executing an interpreted method, executing a jitted method, or jitting a method. This is because other operations could take place, such as, process switches, timer interrupts, key board interrupts, etc. Also, other events could occur during the execution of a method. For example, it is possible that other operations or threads are executing code concurrently. The key to avoiding this problem is in the processing or analysis phase, which could be either real time or post processing. We define a methodology for attributing time spent in a method or process/thread (pid/tid) by identifying the current method or process/thread (pid/tid) as a node and applying base time to the node currently executing whenever a new event occurs. Nodes are either a pid/tid node or a child of a pid/tid node. New child nodes are defined to represent the jitting of a method.