This page contains
Previous inner-Thread tracing approaches
Method Invocations in JVM
In Java the current executed methods are represented as frames, that are stored on a stack. Each frame contains all information that an invocation tracer might need.
When a method is started, it's frame is put on the stack and when it is done the associated frame is removed from the stack. In this way, the current executed method is always on top of the stack.
Each thread has a private stack containing its frames.
This could be used for tracking the method invocations in Java.
Disadvantages:
But the stacks and it's frames not accessible from Java itself and it would be necessary to use an extension library written in C.
This is not acceptable, since it would go against the non-functional requirements and make the tracer platform dependent.
Java Stack Trace approach
TODO: Describe approach
Disadvantages:
- Slow (suboptimal implementation of getStackTrace())
- High memory consumption ( method calls can go very deep)
- There is a possibility that a JVM implementation does not provide this stack, since its not part of the JVM Specification
Own Stack Trace approach
TODO: Describe approach
Disadvantages:
- High memory consumption
- Slow (each method has to do a pop and push)
Method Signature approach
An additional parameter is passed to each method.
Disadvantages:
- High effort to change the native method signatures
Container approach
Method-ID approach
Quote:
"Another possibility to realize the invocation tracer is to add unique identifiers to all available sensors, so that every sensor gets an additional thread Id and a continuous node number in a call tree. This way, the process of building a complete Context Call Tree is divided in several parts: the sensors provide small pieces of information and some kind of tree builder has to provide a basic functionality to connect the gathered values and build a complete context tree out of this multiple node information."
---->Not sure if i understood it right --->
Each thread gets an unique ID and an continuous number for each method invocation done by this thread. This way each invocation can be associated with its thread.
Approach picket in the thesis for the prototype (mixed approach)
Each thread gets a stack, where current active methods are stored. Only monitored methods are considered for the stack.
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