1. A method for optimizing utilization of a programmable logic element in an electronic control unit for vehicles, the programmable logic element comprising a soft CPU and/or an unused remaining area, the method comprising: generating a plurality of model variants that reproduce functionality of the control unit, the model variants differing in scope of computing operations to be executed by a soft CPU; generating a plurality of soft CPU configurations with differing configuration scope, which occupy an area corresponding to the configuration scope of the programmable logic element; executing processor-in-the-loop simulations for different combinations of the plurality of model variants and/or soft CPU configurations, the execution for each combination of model variant and soft CPU configuration includes: instantiation of the soft CPU corresponding to the soft CPU configuration on a programmable logic element located on a development circuit board that is connected to a computer, wherein a program code corresponding to the model variant is downloaded from the computer to the soft CPU; and/or execution of a simulation program, wherein a signal to be processed according to the model variant of the soft CPU is simulated and is transmitted through an appropriate interface from the computer to the soft CPU programmed on the programmable logic element; processing the input signal by the soft CPU; and acquiring and storing the profiling data of the soft CPU with regard to the processing of the input signal.