Patent ID: 7478201
Filing Date: 2009-01-13
Classification: G06F

Abstract:
1. A method of data processing in a data processing system, said method comprising: scrubbing logic in a local coherency domain issuing to at least one cache hierarchy in a remote coherency domain a domain query request, wherein said domain query request is a non-destructive probe of a coherency state associated with a target memory block by said at least one cache hierarchy, and wherein said domain query request does not request a copy of said target memory block and does not request coherency ownership of the target memory block to enable modification of the target memory block; receiving, in the local coherency domain, a coherency response to said domain query request, wherein said coherency response is based upon a response of said at least one cache hierarchy to said domain query request; in response to said coherency response indicating that said target memory block is not cached in said remote coherency domain, updating a domain indication in said local coherency domain to indicate that said target memory block is cached, if at all, only within said local coherency domain; and in response to said coherency response indicating that said target memory block is not cached in said remote coherency domain, at least one cache hierarchy in said local coherency domain updating its respective coherency state for said target memory block from a first state indicating that said memory block may be cached in said remote coherency domain to a second state indicating that said target memory block is cached, if at all, only within said local coherency domain.