How to tell your boss you have too much work

You have a role at work you employ and you, like everyone else, want to rise up the corporate ladder. One of the key people you need to impress is your supervisor but there’s a catch. You don’t see eye-to-eye and cannot seem to agree on ratings of your performance - you think you’re doing a pretty good job, s/he does not. You constantly feel overwhelmed by your ever growing list of responsibilities but are afraid that if you voice these concerns you will be viewed as not up for promotion in future or a pay rise.