A directory system directs cache line access requests from processors in a multi-processor system with a shared memory system through a cache line states directory. The cache line states directory stores a state value that identifies a cache line shared states word. The cache line shared states word identifies the processor that owns the cache line and the state of access of each processor that shares access to the cache line. A state value encoder encodes a cache line shared state word into a s...

Systems and methods for improving the performance of a multiprocessor system by enabling a first processor to initiate the retrieval of data and the storage of the data in the cache memory of a second processor. One embodiment comprises a system having a plurality of processors coupled to a bus, where each processor has a corresponding cache memory. The processors are configured so that a first one of the processors can issue a preload command directing a target processor to load data into the t...

A system control apparatus and method capable of increasing the possibility of recovery from a synchronization error in snooping between system controllers are provided. The system control apparatus has a local port that holds a memory access request received externally and reoutputs it in response to an error retry instruction. A broadcast output section broadcasts the memory access request. A broadcast input section receives the broadcast memory access request. A global port holds the received...

A method, system, computer system, and computer program product to support a distributed environment in which changes to data shared by multiple nodes are logged using private logs and managed by a coordinator. The coordinator recognizes invalidating operations and informs a reader when data need to be read again after an invalidating operation corrupted and/or caused the copy of the data read by the reader to be out-of-date. The coordinator can provide a location from which current valid data c...

A computer system has a plurality of processors in a multiprocessor system with each processor associated with a cache memory. The cache traffic is monitored by the respective processors to determine the load for each of the cache memories. Signals corresponding to the cache loads are generated and analyzed. A target processor is selected for a push data operation from a bus agent to the cache memory using the load information. The push operations to the caches are optimized based on the cache t...

A data processing system includes a plurality of snoopers coupled to an interconnect. In response to a memory access request transmitted on an interconnect by one of the snoopers receiving a Retry response, a determination is made whether or not the Retry response was caused by a target snooper that will service the memory access request. If not, the target snooper services the memory access request in spite of the Retry response. In a preferred embodiment in which the memory access request is a...

A non-uniform memory access (NUMA) computer system includes a node interconnect to which a remote node and a home node are coupled. The home node contains a home system memory, and the remote node includes at least one processing unit and a cache. In response to the cache deallocating an unmodified cache line that corresponds to data resident in the home system memory, a cache controller of the cache issues a deallocate operation on a local interconnect of the remote node. In one embodiment, the...

According to one embodiment, a method is disclosed. The method includes receiving a first request from a first node in a multi-node computer system to invalidate a first cache line at a second node. The method also includes receiving a second request from the second node to invalidate the first cache line at the first node and detecting the concurrent requests at conflict detection circuitry.

An information carrier medium containing software that, when executed by a processor, causes the processor to receive status information from circuit logic that collects the status information from caches associated with different processor cores. The software also causes the processor to provide the information to a user of the software. The status information indicates whether one of the caches comprises an entry associated with a virtual address.

An information carrier medium containing software that, when executed by a processor, causes the processor to receive information from caches on different cache levels. The caches comprise a plurality of cache line addresses, each cache line address associated with a corresponding name. The software causes the processor to display the information on a graphical user interface (GUI), the GUI cross-referencing each of the cache line addresses with a corresponding name.