Trim the pork sirloin roast of any excess fat. If the roast is an uneven shape, use some kitchen twine to tie it into a more uniform shape, similar to a football.
In a small bowl mix together the garlic, rosemary, sea salt, black pepper and olive oil. Spread all over the pork tenderloin so that it is evenly coated. Place in the fridge to marinate for 4-6 hours.
Set the smoker to 275F using wood chips of choice. I used hickory wood.
Smoke the pork until it reaches an internal temperature of 165F, approximately 3 - 3 1/2 hours.
Remove the pork roast from the smoker and place in the fridge to chill.
Once chilled, use a meat slicer to cut the pork roast into thin lunchmeat slices.