Provided no non-confidence motion succeeds  after prorogation the next federal may be even further away.  Under the original Westminster parliamentary rules provided no non-confidence motion succeeds a federal election would not be required until 2026, a full five years from the last election.  
 References: Section 50 of the Constitution Act, 1867, plus Section 4 of the Charter. Five years. Notice that the Constitution Act section trumps the fixed date legislation.