Abstract: User-controlled targeted cache purging includes receiving a request to perform an operation to purge data from a cache, the request including an index identifier identifying an index associated with the cache. The index specifies a portion of the cache to be purged. The user-controlled targeted cache purging also includes purging the data from the cache, and providing notification of successful completion of the operation.

Abstract: A method of managing a temporary memory includes: receiving a request to transfer data from a source location to a destination location, the data transfer request associated with an operation to be performed, the operation selected from an input into an intermediate temporary memory and an output; checking a two-state indicator associated with the temporary memory, the two-state indicator having a first state indicating that an immediately preceding operation on the temporary memory was an input to the temporary memory and a second state indicating that the immediately preceding operation was an output from the temporary memory; and performing the operation responsive to one of: the operation being an input operation and the two-state indicator being in the second state, indicating that the immediately preceding operation was an output; and the operation being an output operation and the two-state indicator being in the first state, indicating that the immediately preceding operation was an input.

Abstract: A method of preventing lockout and stalling conditions in a multi-node system having a plurality of nodes which includes initiating a processor request to a shared level of cache in a requesting node, performing a fabric coherency establishment sequence on the plurality of nodes, issuing a speculative memory fetch request to a memory, detecting a conflict on one of the plurality of nodes and communicating the conflict back to the requesting node within the system, canceling the speculative memory fetch request issued, and repeating the fabric coherency establishment sequence in the system until the point of conflict is resolved, without issuing another speculative memory fetch request. The subsequent memory fetch request is only issued after determining the state of line within the system, after the successful completion of the multi-node fabric coherency establishment sequence.

Abstract: A two pipe pass method for least recently used (LRU) compartment capture in a multiprocessor system. The method includes receiving a fetch request via a requesting processor and accessing a cache directory based on the received fetch request, performing a first pipe pass by determining whether a fetch hit or a fetch miss has occurred in the cache directory, and determining an LRU compartment associated with a specified congruence class of the cache directory based on the fetch request received, when it is determined that a fetch miss has occurred, and performing a second pipe pass by using the LRU compartment determined and the specified congruence class to access the cache directory and to select an LRU address to be cast out of the cache directory.

Abstract: The method includes initiating a processor request to a cache in a requesting node and broadcasting the processor request to remote nodes when the processor request encounters a local cache miss, performing a directory search of each remote cache to determine a state of a target line's address and an ownership slate of a specified address, returning the state of the target line to the requesting node and forming a combined response, and broadcasting the combined response to each remote node. During a fetch operation, when the directory search indicates an IM or a Target Memory node on a remote node, data is sourced from the respective remote cache and forwarded to the requesting node while protecting the data, and during a store operation, the data is sourced from the requesting node and protected while being forwarded to the IM or the Target Memory node after coherency has been established.

Abstract: A method, system and computer program product for selectively purging entries in a cache of a computer system. The method includes determining a starting storage address and a length of the storage address range to be purged, determining preset values for a congruence class and a compartment of a cache directory, accessing the cache directory based on the preset value of the congruence class, and selecting an entry in the cache directory based on the preset value of the compartment, determining validity of the entry accessed by examining an ownership tag of the entry, comparing a line address of the entry with the starting storage address and a sum of the starting storage address and the length of the storage address range, and selectively purging the entry based on the comparison result.

Abstract: A method of preventing lockout and stalling conditions in a multi-node system having a plurality of nodes which includes initiating a processor request to a shared level of cache in a requesting node, performing a fabric coherency establishment sequence on the plurality of nodes, issuing a speculative memory fetch request to a memory, detecting a conflict on one of the plurality of nodes and communicating the conflict back to the requesting node within the system, canceling the speculative memory fetch request issued, and repeating the fabric coherency establishment sequence in the system until the point of conflict is resolved, without issuing another speculative memory fetch request. The subsequent memory fetch request is only issued after determining the state of line within the system, after the successful completion of the multi-node fabric coherency establishment sequence.