Combine the dry ingredients (minus the olive oil) in a bowl and mix thoroughly.
Rub pork tenderloin with olive oil and sprinkle the seasoning evenly on all sides of the roast.
Place the beef tenderloin directly on the smoker rack away from direct heat.
Smoke for about 1 hour at 250°F until an internal temperature of 110°F.
Transfer roast to heated grill set to 500°+ and sear on all sides for a 5 minutes total. Check internal temperature of meat with thermometer to make sure the roast doesn't go over 120-125°F. (If no grill is available, sear in a pan atop the stove or broil in the oven)
Allow to rest for 10 minutes before slicing into 1" pieces. Roast should have risen to 130-135°F by time of carving. Serve with your favorite side dishes and enjoy!
Notes
It's better to pull the meat off the smoker early than late, tenderloin gets dry if overcooked.
Tenderloin can be seared in a pan atop the stove or in the oven on broil if a propane grill is not available.
Serve with a horseradish sauce and slice the roast into fairly thick pieces for the best presentation.