You can easily compare how much faster a simulation runs with a DLL than using Notify At Simulation End. It displays how long it takes to run a simulation in simulated time and real time.
To compare performance
1. Choose Simulate > Simulation Properties; then click the Preferences tab.
2. Activate Notify At Simulation End and click OK.
3. Disconnect the DLL from the diagram.
4. Run the simulation.
5. Reconnect the DLL to the diagram and disconnect the corresponding compound block from the diagram.
6. Run the simulation.
7. Compare the real-time simulation results from the two simulation runs.