I got my model to work on multiple cores with these docs:
https://www.mathworks.com/help/releases/R2017b/simulink/ug/configure-your-model.html
https://www.mathworks.com/help/releases/R2017b/simulink/ug/choose-a-target-architecture.html
There is a toolbox available in MATLAB for parallel computing called the "Parallel Computing Toolbox". You can try taking a look at it. https://de.mathworks.com/help/distcomp/index.html
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