A method and system for selectively enabling a cache-invalidate function supplement to a resource-synchronization instruction such as test-and-set. Some embodiments include a first processor, a first memory, at least a first cache between the first processor and the first memory, wherein the first cache caches data accessed by the first processor from the first memory, wherein the first processor executes: a resource-synchronization instruction, an instruction that enables a cache-invalidate function to be performed upon execution of the resource-synchronization instruction, and an instruction that disables the cache-invalidate function from being performed upon execution of the resource-synchronization instruction.