Oracle International Corporation

Intel Corporation

Joann Lam

Ramaswamy Sivaramakrishnan

Robert N Hasbun

Hoyeol Cho

Peter J Ruscito

David Smentek

Jinho Kwack

Connie Wai Mun Cheung

Serena Leung

Madhavi Kondapaneni

Asad Faizi

Claire Ni

A method and apparatus for snooping caches is disclosed. In one embodiment, a system includes a number of processing nodes and a cache shared by each of the processing nodes. The cache is partitioned such that each of the processing nodes utilizes only one assigned partition. If a query by a processing node to its assigned partition of the cache results in a miss, a cache controller may determine whether to snoop other partitions in search of the requested information. The determination may be made based on history of where requested information was obtained from responsive to previous misses in that partition.

Method and apparatus for history-based snooping of last level caches

Embodiments include systems and methods for improving power consumption characteristics of reverse directories in microprocessors. Some embodiments operate in context of multiprocessor semiconductors having cache hierarchies in which multiple higher-level caches share lower-level caches. Lower-level cache is coupled with reverse directories associated with respective ones of the higher-level caches. Each reverse directory can be segregated into two reverse sub-directories, one reverse sub-directory for relatively high-frequency accesses (e.g., updating 'valid' and/or 'private' information), and the other reverse sub-directories for relatively low-frequency accesses updating &#x201c;index&#x201d; and &#x201c;way&#x201d; information). During a write mode operation, when the reverse directories are updated, the write operation is performed only on the sub-directories having the entries invoked by the update, such that write operations can frequently consume only a fraction (e.g., halt) of the power of a conventional reverse directory write operation.

Power saving for reverse directory

A method including: receiving multiple local requests to access the cache line; inserting, into an address chain, multiple entries corresponding to the multiple local requests; identifying a first entry at a head of the address chain; initiating, in response to identifying the first entry and in response to the first entry corresponding to a request to own the cache line, a traversal of the address chain; setting, during the traversal of the address chain, a state element identified in a second entry; receiving a foreign request to access the cache line; inserting, in response to setting the state element, a third entry corresponding to the foreign request into the address chain after the second entry; and relinquishing, in response to inserting the third entry after the second entry in the address chain, the cache line to a foreign thread after executing the multiple local requests.

Request to own chaining in multi-socketed systems

A flash EEPROM memory array including a cache buffer for storing lines of data being written to all addresses in main memory; a plurality of holding buffers for storing lines of data from the cache buffer addressed to a particular block of addresses in main memory; a plurality of blocks of flash EEPROM main memory for storing lines of data from a holding buffer directed to a particular block of addresses in main memory; and control circuitry for writing lines of data addressed to a particular block of addresses in main memory from the cache buffer to a holding buffer when the cache buffer fills or a holding buffer limit is reached whichever occurs first, writing valid data from an addressed block of flash memory to lines of the holding buffer not holding valid data written from the cache buffer, erasing the addressed block of flash memory, and writing all of the lines in the holding buffer to the addressed block of flash memory.

Flash EEPROM main memory in a computer system

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San Francisco, CA, United States of America

Joann Lam