Long time spent in simulink.c​ompiler.ge​tSimulatio​nOutput in postStepFcn that increases over time?

I have a model I am trying to run with Simulink Compiler with live plotting using the postStepFcn. I notice that the pace of my simulation is slow. When using the profiler I see most of the time is spent in simulink.compiler.getSimulationOutput. I notice this function returns all the data for the simulation up to the current point. For a long running simulation this could be a lot of data and the time will increase as the simulation goes forward. Are there any alternatives?

Fetch the partial simulation output during simulation run time - MATLAB simulink.compiler.getSimulationOutput (mathworks.com)

Answer 1

[MathWorks Support Team]

Solution 1: PostStepFcn decimation. Consider using the decimation option of the postStepFcn. This can significantly improve performance by running the postStepFcn at a slower rate.

Solution 2: Use setExternalOutputFcn instead of simulink.compiler.getSimulationOutput

Can be used in conjunction with solution 1. Consider turning off all logging and instead using the setExternalOutputFcn to get the output of the simulation. This function will only return the output at the current step which can be faster for long simulations.

Set callback to read external root outport block data after each simulation step - MATLAB simulink.compiler.setExternalOutputsFcn (mathworks.com)

If you need to save some amount of historical data, consider implementing a circular buffer that is written to in the ExternalOutputFcn. Attached is an example of how to implement a circular buffer. In the example, a figure is used instead of App Designer but the concept translates to App Designer apps.