When I simulate the following model, the CPU time increases unexpectedly:

model WithoutChatter
  Real x;
initial equation
  x = 2;
equation
  der(x) = if noEvent(x>=1) then -1 else 1;
end WithoutChatter;

With the noEvent operator, the CPU time should not go up noticeably, like it is explained here, from where I copied the example code:
Modelica by Example

I am new to OpenModelica and just did a Windows installation. For the simulation I used default settings. The result is this.
CPU time increases