The difference between the word performance and the word function

Is the following logically and grammatically correct?


Performance refers to the demonstrations of one's ability, while function refers to the ability itself. Take the kidneys' function as an example: The function of kidneys refer to all the abilities that kidneys have, while the performance of kidneys refers to a functional demonstration of kidneys.

I don't think function and ability are the same thing. A person or thing may or may not be able to fulfill its function. One of the functions of the kidneys is to filter blood. But sometimes they fail to do it, which may kill the person or animal. Franz Reichelt's parachute's function was to allow him to survive falling from the Eiffel Tower. Its inability to do so was caught on film.