Hi Oldrich,
The increase in CPU load when substituting manual code with generated code from the Simulink model can arise due to the inherent complexity and computational requirements of the generated code. The following steps can be taken to reduce the CPU load:
Simplifying the complex subsystems and removing unnecessary blocks will reduce the overall computational load. This can significantly decrease the CPU usage.
Some code generation settings can be helpful, like “Default parameter behavior”, which when set to “Inlined” can help reduce overhead by embedding parameter values directly in the code. This option can be found in the path: Configuration Parameters > Code Generation > Optimization > Default parameter Behavior. For more details on the “Inlined” parameter, please refer to this link - https://www.mathworks.com/help/rtw/ref/defaultparameterbehavior.html
Another option is to lower the “Loop unrolling threshold”, which can help improve execution speed by reducing the overhead of loop control. This option can be found in the path: Configuration Parameters > Optimization > Loop unrolling threshold. For more details on the “Loop unrolling threshold” parameter, please refer to this link - https://www.mathworks.com/help/rtw/ref/loopunrollingthreshold.html
Also ensure that the “Block reduction” option is checked under Configuration Parameters > Simulation Target > Advanced parameters > Block reduction. This removes redundant blocks during code generation. For more information on the “Block reduction” parameter, please refer to this link - https://www.mathworks.com/help/simulink/gui/blockreduction.html
Please refer to this MATLAB Answer by a staff member regarding handling CPU load for generated code - https://www.mathworks.com/matlabcentral/answers/1984294-how-to-use-more-cpu-in-simulink-for-a-power-system-simulation
Regarding your follow-up question, estimating the CPU load can be done using a software-in-the-loop (SIL), processor-in-the-loop (PIL), or XCP-based external mode simulation that produces execution-time metrics for your generated code. Please refer to this documentation link for a detailed description of the workflow involved in using these methods - https://www.mathworks.com/help/ecoder/ug/view-and-compare-code-execution-times.html
I hope this helps!
Raghava
