Patent ID: 7529889
Filing Date: 2009-05-05
Classification: G06F,Y02D

Abstract:
1. A data processing apparatus comprising: at least one processing unit for performing operations; a cache having a plurality of cache lines for storing data values for access by the at least one processing unit when performing said operations; the at least one processing unit providing a plurality of sources from which access requests are issued to the cache, each access request specifying an address of a data value the subject of that access request, and each access request further including a source identifier indicating which of said plurality of sources issued that access request; cache control logic, responsive to each access request, to cause a lookup procedure to be performed in said cache, a hit condition occurring if the lookup procedure identifies that the data value the subject of the access request is in the cache; a storage element configured to store, for each source, an indication as to whether a last access request from that source resulted in said hit condition; cache line identification logic configured, for each access request, to determine whether that access request is seeking to access a same cache line as the last access request issued by that source; said cache comprising a plurality of storage blocks in which said lookup procedure can be performed, the cache comprising a plurality of cache ways, said plurality of storage blocks comprising a plurality of way blocks for storing data values, each way block being associated with one of said cache ways; said cache control logic configured, for each access request, to identify from the source identifier the source of the access request; said cache control logic also configured, if the cache line identification logic determines that the access request is to the same cache line as the last access request issued by that source, and the storage element indicates that the last access request from that source resulted in said hit condition, to constrain said lookup procedure to only a subset of said way blocks.