You can make use of the Profiler to know where the most number of method calls are present. The Profiler is in the "Debugger" section of the Ribbon bar. To try, click on Activate Profiler when you start the SImulation. After few moments, click on "Show Profile". You will get a report of the the top 50 most relevant methods as well as the top 50 call cycles in your model, including the time for each of the calls etc.
Based on this, you can reduce the Simulation time by reconfiguring the methods taking the most amount of time by decreasing for example, loops in your methods etc. For more Information, read the Documentation about the "Profiler" in the Step-by-step help. Hope this helps.