EP0348628A2
Expired / Lapsed
EP
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Cache storage system
Assignee: International Business Machines Corp
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Filing: 1989-04-26
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Granted: —
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Expires: 2009-04-26
Abstract
Abstract Multi level cache storage system for a multiprocessor system in which each processor has a level one cache storage unit which interfaces with a level two cache unit and main storage unit shared by all processors. The multiprocessors share the level two cache according to a priority algorithm. When data in the level two cache is updated, corresponding data in level one caches is invalidated until it is updated.
Inventors
- 👤 Patrick Wayne Gallagher
- 👤 Steven Lee Gregor
- 👤 Stephen Michael Reeve
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 09:27
CPC Classifications
G; G06; G06F; G06F12/00; G06F12/02; G06F12/08; G06F12/0802; G06F12/0806; G06F12/0811; G06F12/0893; G06F12/0897
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
102 words
Cache storage system for a data processing system containing a main storage (L3) unit and a plurality of multiprocessors, characterized by a plurality of first level cache (L1) storage units, each of which is associated with one of said plurality of multiprocessors; by a second level cache storage unit shared by all of said cache storage unit and said main storage unit; by a central directory containing only said first level cache status information; and by control means for said second level cache unit including priority means for a handling multiple requests for storage service coming from said first level cache units.
Claim 2
Dependent Claim
102 words
Cache storage system for a data processing system containing a main storage (L3) unit and a plurality of multiprocessors, characterized by a plurality of first level cache (L1) storage units, each of which is associated with one of said plurality of multiprocessors; by a second level cache storage unit shared by all of said cache storage unit and said main storage unit; by a central directory containing only said first level cache status information; and by control means for said second level cache unit including priority means for a handling multiple requests for storage service coming from said first level cache units.
Claim 3
Dependent Claim
19 words
A system according to claim 1, characterized in that the priority means assigns priority on a round robin basis.
Claim 4
Dependent Claim
60 words
Cache storage system according to claim 1, characterized by a plurality of first level (L1) store-through cache storage units, each of which is individually associated with a single one of said multiprocessors, a storage subsystem having a second level (L2) store-in cache storage unit, and a main storage (L3) unit for storing data for all of said plurality of multiprocessors.
Claim 5
Dependent Claim
64 words
Cache storage system as set forth in claim 1, characterized by L2 cache directory means for identifying data stored in said L2 cache; by storage consistency means responsive to a modification of data in an L1 cache by its associated first multiprocessing unit for searching said L2 cache director any modifying the data therein to correspond to the modified data in said L1 cache.
Claim 6
Dependent Claim
73 words
Cache storage system according to claim 4, characterized in that the storage consistency means further includes means for inhibiting reacess to said modified data by said first multiprocessing unit until said other multiprocessing units have modified data in their associated L1 cache units to correspond to modified data in said L2 cache unit, a command buffer request queue for each of said multiprocessors, a store queue request queue for each of said multiprocessors.
Claim 7
Dependent Claim
72 words
Cache storage system as set forth in one of claims 1 or 4 or 5, characterized by an inpage completion request queue for each of said multiprocessors, by a storage queue request queue for each of said multiprocessors, by an inpage completion request queue for each of said multiprocessors, by an inpage completion request queue for each of said multiprocessors; and by a command buffer request queue for each of said multiprocessors.
Claim 8
Dependent Claim
60 words
Cache storage system according to claim 4, characterized in that the buffer subsystem includes a not-in-here status but for each line of said L2 cache unit and means responsive to a write command which places all new data in one of said lines and its associated not-in-here bit for inhibiting the inpage of data from said L3 main storage unit.
References Cited (Backward Citations)
No citation records indexed.
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