Run and debug on multiple simulators
Sometimes you may need to run or debug one application build on several simulators simultaneously, for example, when you want to check your layout in different iPhone's screen size. In this case, you just need to enable the parallel run in the run/debug configuration settings.
Allow parallel run
Select Edit Configurations from the run/debug configuraton selector on the toolbar.from the main menu or
Choose your configuration from the list.
Select the Allow parallel run checkbox and click OK.
When you launch an application on a simulator after enabling the parallel run, the green dots appear on the toolbar and in the Run or Debug tool window. This indicates that now your application can run on different simulators at the same time.
To launch another simulator, choose it from the run/debug configuration selector and click or .
The number of running devices is shown on the toolbar:
To stop one of the running applications, click ⌘F2 and select it form the list that opens. To stop them all, select Stop All.