1. A processor comprising: a decoder to decode a load_check instruction; and an execution unit in response to the load_check instruction, to cause a user-configurable attribute stored in a cache line to be read from the cache line and compared with an expected value; said execution unit further in response to the load_check instruction, when the user-configurable attribute does not equal the expected value, to cause a light-weight yield to occur, wherein the user-configurable attribute is to indicate whether a thread of a multi-threaded program may access information stored in the cache line.