Reverse directory for facilitating accesses involving a lower-level cache

摘要

One embodiment of the present invention provides a multiprocessor system that includes a number of processors with higher-level caches that perform memory accesses through a lower-level cache. This multiprocessor system also includes a reverse directory coupled to the lower-level cache, which includes entries corresponding to lines in the higher-level caches, wherein each entry identifies an associated entry in the lower-level cache. In one embodiment of the present invention, the higher-level cache is a set-associative cache, and storing the information within the reverse directory specifies a way location in the higher-level cache in which the line is to be stored. The system is configured to use this way information during a subsequent invalidation operation to invalidate the line in the higher-level cache without having to perform a lookup in the higher-level cache to determine the way location of the line in the higher-level cache.