| 摘要 |
In addition to an address tag, a coherency state and an LRU position, each cache directory entry includes historical processor access and snoop operation information for the corresponding cache line. The historical processor access and snoop operation information includes different subentries for each different processor which has accessed the corresponding cache line, with subentries being "pushed" along the stack when a new processor accesses the subject cache line. Each subentries contains the processor identifier for the corresponding-processor which accessed the cache line, a processor access history segment, and a snoop operation history segment. The processor access history segment contains one or more opcodes identifying the operations which were performed by the processor, and timestamps associated with each opcode. The snoop operation history segment contains, for each operation snooped by the respective processor, a processor identifier for the processor originating the snooped operation, an opcode identifying the snooped operation, and a timestamp identifying when the operation was snooped. This historical processor access and snoop operation information may then be utilized by the cache controller to influence victim selection, coherency state transitions, LRU state transitions, deallocation timing, and other cache management functions so that smaller caches are given the effectiveness of very large caches through more intelligent cache management.
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