What is the test for excessive physical force in violation of the Eighth Amendment?

In order to determine whether prison officials used excessive physical force in violation of the Eighth Amendment, the core inquiry is whether force was applied in a good faith effort to maintain or restore discipline, or maliciously and sadistically to cause harm. Hudson v. McMillan, 112 S.Ct. 995, 999 (1992). To decide whether use of force was wanton and unnecessary, the court must examine the necessity of the force, the relationship between necessity and amount of force used, the threat reasonably perceived by the responsible officials and any efforts made to temper the severity of a forceful response. Id.