6.5. Section D.12: Other Optimizations and Determinism Rules

Q: D.12(7)

The overhead associated with obtaining a mutual-exclusive access to an entry-less protected object. This shall be measured in the following way:

For a protected object of the form:

protected Lock is
   procedure Set;
   function Read return Boolean;
private
   Flag : Boolean := False;
end Lock;
protected body Lock is
   procedure Set is
   begin
      Flag := True;
   end Set;
   function Read return Boolean
   Begin
      return Flag;
   end Read;
end Lock;

The execution time, in processor clock cycles, of a call to Set. This shall be measured between the point just before issuing the call, and the point just after the call completes. The function Read shall be called later to verify that Set was indeed called (and not optimized away). The calling task shall have sufficiently high priority as to not be preempted during the measurement period. The protected object shall have sufficiently high ceiling priority to allow the task to call Set.

For a multiprocessor, if supported, the metric shall be reported for the case where no contention (on the execution resource) exists from tasks executing on other processors.