DATA PROCESSING SYSTEM IMPLEMENTED HAVING A DISTRIBUTED CACHE

In a data processing system having a local first level cache which covers an address range of a backing store, a distributed second level cache has a plurality of distributed cache portions, each assigned as a home cache portion for a corresponding non-overlapping address sub-range of the address range of the backing store. Upon receipt of a read access request to a read-only address location of the backing store, the local first level cache is configured to, when the read-only address location misses in the local first level cache, send the read access request to a most local distributed cache portion of the plurality of distributed cache portions for the local first level cache to determine whether the read-only access location hits or misses in the most local distributed cache portion, in which the most local distributed cache portion is not the home cache portion for the read-only address location.