Advanced Event Tracing

Principle

MicroEJ Core Engine allows method execution to be profiled. The following two new hooks functions are used for that:

LLMJVM_MONITOR_IMPL_on_invoke_method called at the start of the method invocation.
LLMJVM_MONITOR_IMPL_on_return_method called when returning from the invoked method.

Calling these functions each time a method is invoked will slow down the application execution, so these functions are not called by default when event tracing is enabled and started.

Note

This feature requires Architecture version 7.17.0 or higher and is only available on MicroEJ Core Engine, not on Simulator.

To activate them, you need to follow these steps:

Enable and start the trace see here
Tell the third-party linker program to redirect all calls to LLMJVM_invoke_method and LLMJVM_return_method symbols to respectively LLMJVM_invoke_method_with_trace and LLMJVM_return_method_with_trace symbols.

Platforms using GNU LD linker

Add the following options to the LD linker command line:

--require-defined=LLMJVM_invoke_method_with_trace
--defsym=LLMJVM_invoke_method=LLMJVM_invoke_method_with_trace
--require-defined=LLMJVM_return_method_with_trace
--defsym=LLMJVM_return_method=LLMJVM_return_method_with_trace

Platforms using IAR ILINK linker

Pass the following options to the ILINK linker program

--redirect LLMJVM_invoke_method=LLMJVM_invoke_method_with_trace
--redirect LLMJVM_return_method=LLMJVM_return_method_with_trace