There is no meaningful solution for continuous time models. Continuous time models use ode solvers that can reject steps in order to stay within integration tolerance, so the required time can vary depending on the initial conditions and the prediction model. The prediction model can take variable step sizes so the time per change of the independent variable can change during execution.
For discrete time models if rapid acceleration is turned on then Simulink divides the work up into tasks according to required rate, and executes some tasks less often and executes some tasks in parallel. The portions of the model that are grouped together into tasks are not necessarily functionally related, they might just happen to be running at the same rate.
At the best of times there are items that have to be executed for every minor time step and items that are every major time step, so the work over time depends on where you are in major vs minor steps.
