Intel Corporation
METHOD AND APPARATUS FOR SMART STORE OPERATIONS WITH CONDITIONAL OWNERSHIP REQUESTS

Abstract:

Method and apparatus implementing smart store operations with conditional ownership requests. One aspect includes a method implemented in a multi-core processor, the method comprises: receiving a conditional read for ownership (CondRFO) from a requester in response to an execution of an instruction to modify a target cache line (CL) with a new value, the CondRFO identifying the target CL and the new value; determining from a local cache a local CL corresponding to the target CL; determining a local value from the local CL; comparing the local value with the new value; setting a coherency state of the local CL to (S)hared when the local value is same as the new value; setting the coherency state of the local CL to (I)nvalid when the local value is different than the new value; and sending a response and a copy of the local CL to the requester. Other embodiments include an apparatus configured to perform the actions of the methods.