Profiling does not have any effect on your application’s execution speed on hardware.

Downloading your image to the target can take a little longer than normal when you enable profiling. You may also notice a delay when you terminate execution while analysis report is being generated. The amount of time required to generate an analysis file depends on varying factors, such as the sample rate and whether or not you have enabled program trace. The Backlog field in the live update view gives you a good indication of how much longer is needed for the ARM Profiler to create an analysis file.