Oracle International Corporation

David Smentek

Ramaswamy Sivaramakrishnan

Paul N Loewenstein

Kathirgamar Aingaran

Serena Leung

Manling Yang

Sumti Jairath

Ali Vahidsafa

Serena Wing Yee Leung

Mark Luttrell

Thomas M Wicki

Stephen Phillips

Venkatram Krishnaswamy

Connie Wai Mun Cheung

Damien Walker

Thirumalai Swamy Suresh

Joann Lam

A cache memory that selectively enables and disables speculative reads from system memory is disclosed. The cache memory may include a plurality of partitions, and a plurality of registers. Each register may be configured to stored data indicative of a source of returned data for previous requests directed to a corresponding partition. Circuitry may be configured to receive a request for data to a given partition. The circuitry may be further configured to read contents of a register corresponding to the given partition, and initiate a speculative read dependent upon the contents of the register.

History based memory speculation for partitioned cache memories

A system is disclosed in which the system may include multiple bus switches, and multiple processors. Each processor may be coupled to each bus switch. Each processor may be configured to initiate a transfer of data to a given bus switch, and detect if a respective link to the given bus switch is inoperable. In response to detecting an inoperable link to a first bus switch, a given processor may be further configured to send a notification message to at least one other processor via at least a second bus switch and to remove routing information corresponding to the inoperable link from a first register. The at least one other processor may be configured to remove additional routing information corresponding to the inoperable link from a second register in response to receiving the notification message from the given processor.

Inter-processor bus link and switch chip failure recovery

A method and apparatus for performing non-temporal write combining using existing cache resources is disclosed. In one embodiment, a method includes executing a first thread on a processor core, the first thread including a first block initialization store (BIS) instruction. A cache query may be performed responsive to the BIS instruction, and if the query results in a cache miss, a cache line may be installed in a cache in an unordered dirty state in which it is exclusively owned by the first thread. The first BIS instruction and one or more additional BIS instructions may write data from the first processor core into the first cache line. After a cache coherence response is received, the state of the first cache line may be changed to an ordered dirty state in which it is no longer exclusive to the first thread.

Non-temporal write combining using cache resources

A method and system for allocating data streams that includes receiving, at an allocator, a data stream. The data stream includes a memory address and data associated with the memory address. The method also includes examining, by the allocator, the data stream to make a determination that the data stream is a soft allocating data stream, and then sending, from the allocator based on the determination, a plurality of write probes to a plurality of caches, wherein each write probe of the plurality of write probes includes at least part of the memory address. Additionally, the method includes receiving, at the allocator in response to a write probe of the plurality of write probes, a cache line present acknowledgement from a cache of the plurality of caches, and directing, by the allocator in response to the cache line present acknowledgement, the data of the data stream to the cache.

Cache probe request to optimize I/O directed caching

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

A method and system for dynamic flow control using credit sharing that includes allocating portions of credits to senders, wherein each of the credits is for communicating with a receiver; transmitting, by a first sender of the senders, a first message to the receiver using a first credit of a first portion of the credits; decrementing, in response to transmitting the first message, a credit balance of the first sender by one; and determining that the credit balance of the first sender is zero. The method also includes sending to a second sender of the senders, by the first sender, in response to the credit balance being zero, a first request for a second credit; receiving from the second sender, in response to the first request, a first response comprising the second credit; and transmitting, by the first sender, a second message to the receiver using the second credit.

Dynamic flow control using credit sharing

A method for removal of an offlining cache agent, including: initiating an offlining of the offlining cache agent from communicating with a plurality of participating cache agents while a first transaction is in progress; setting, based on initiating the offlining, an ignore response indicator corresponding to the offlining cache agent on each of the plurality of participating cache agents; offlining, based on setting the ignore response indicator, the offlining cache agent; and ignoring, based on setting the ignore response indicator, a first response to the transaction from the offlining cache agent.

Method and system for removal of a cache agent

A method for cache coherence, including: broadcasting, by a requester cache (RC) over a partially-ordered request network (RN), a peer-to-peer (P2P) request for a cacheline to a plurality of slave caches; receiving, by the RC and over the RN while the P2P request is pending, a forwarded request for the cacheline from a gateway; receiving, by the RC and after receiving the forwarded request, a plurality of responses to the P2P request from the plurality of slave caches; setting an intra-processor state of the cacheline in the RC, wherein the intra-processor state also specifies an inter-processor state of the cacheline; and issuing, by the RC, a response to the forwarded request after setting the intra-processor state and after the P2P request is complete; and modifying, by the RC, the intra-processor state in response to issuing the response to the forwarded request.

Broadcast cache coherence on partially-ordered network

Implementations of the present disclosure involve an apparatus and/or method for communicating between domains of a computing system, where at least one of the domains operates on a skipped clock signal. Communication from a skipped clock domain to a non-skipped clock domain, or free running domain, may include a valid signal component configured to indicate when a new data packet is available and one or more counters associated with the domains to count received data packets for acknowledgement or credit purposes. The free running domain may receive data packets from any number of skipped clock domains through the communication scheme described herein. Communication from a free running domain to a skipped clock domain may include delaying transmitted data packets to correspond with the cycles of the skipped clock signal to ensure that transmitted data packets arrive at the skipped clock domain to be properly read on a skipped clock cycle.

Growing community of inventors

Cupertino, CA, United States of America

David Smentek