Directory caches, and methods for operation thereof
AssigneeHewlett-Packard Development Company, L.P.
InventorsErin A. Handgen, Leith L. Johnson
Life of this patent
Estimating the term…
Abstract
A directory cache is provided with a plurality of directory entries configured to store information regarding copies of memory lines stored in a plurality of caches. The entries are divided into sets of N entries, with each set of N entries being addressable via an index. The directory cache is also provided with a cache controller. The cache controller retrieves a set of N entries associated with an index corresponding to a memory line, and if a tag portion of one of the retrieved entries corresponds to the memory line, the cache controller determines whether the one of the retrieved entries contains an indication that information regarding the memory line is stored in at least a second one of the retrieved entries.
Claims27
A directory cache, comprising:
- a plurality of directory entries configured to store information regarding copies of memory lines stored in a plurality of caches, the entries being divided into sets of N entries, with each set of N entries being addressable via an index;
- and
- a cache controller configured to, retrieve a set of N entries associated with an index corresponding to a memory line;
- and
- if a tag portion of one of the retrieved entries corresponds to the memory line, then determine whether the one of the retrieved entries contains an indication that information regarding the memory line is stored in at least a second one of the retrieved entries.
A directory cache, comprising:
- a plurality of directory entries configured to store information regarding copies of memory lines stored in a plurality of caches;
- and
- a cache controller configured to, if a copy of a memory line is stored in M or fewer of the caches, store information regarding the memory line in a single one of the directory entries, and if a copy of the memory line is stored in greater than M of the caches, then 1) store, in a first of the directory entries, A) information regarding the memory line, and B) an indication that additional information regarding the memory line is stored in at least a second one of the directory entries, and 2) store, in the second one of the directory entries, information indicative of plural ones of the caches in which the memory line is stored.
A method of operating a directory cache that stores information regarding copies of memory lines stored in a plurality of caches, the method comprising:
- indexing a directory cache, with at least part of an address corresponding to a memory line, to retrieve a set of N entries from the directory cache;
- and
- if a tag portion of one of the retrieved entries corresponds to the memory line, then determining whether the one of the retrieved entries contains an indication that information regarding the memory line is stored in at least a second one of the retrieved entries.
A method of operating a directory cache that stores information regarding copies of memory lines stored in a plurality of caches, the method comprising:
- if a copy of a memory line is stored in M or fewer of the caches, storing information regarding the memory line in a single directory entry of the directory cache;
- and
- if a copy of the memory line is stored in greater than M of the caches, then, storing, in a first of the directory entries, A) information regarding the memory line, and B) an indication that additional information regarding the memory line is stored in at least a second one of the directory entries;
- and
- storing, in the second one of the directory entries, information indicative of plural ones of the caches in which the memory line is stored.
Dependencies are inferred from the claim text.