Abstract: A computer implemented method of embedded dynamic random access memory (EDRAM) macro disablement. The method includes isolating an EDRAM macro of a cache memory bank, the cache memory bank being divided into at least three rows of a plurality of EDRAM macros, the EDRAM macro being associated with one of the at least three rows. Each line of the EDRAM macro is iteratively tested, the testing including attempting at least one write operation at each line of the EDRAM macro. It is determined that an error occurred during the testing. Write perations for an entire row of EDRAM macros associated with the EDRAM macro are disabled based on the determining.

Abstract: A method and apparatus for eliminating, in a multi-nodes data handling system, contention for exclusivity of lines in cache memory through improved management of system buses, processor cross-invalidate stacks, and the system operations that can lead to these requested cache operations being rejected.

Abstract: Maintaining cache coherence in a multi-node, symmetric multiprocessing computer, the computer composed of a plurality of compute nodes, including, broadcasting upon a cache miss by a first compute node a request for a cache line; transmitting from each of the other compute nodes to all other nodes the state of the cache line on that node, including transmitting from any compute node having a correct copy to the first node the correct copy of the cache line; and updating by each node the state of the cache line in each node, in dependence upon one or more of the states of the cache line in all the nodes.

Abstract: Embedded dynamic random access memory (EDRAM) macro disablement in a cache memory includes isolating an EDRAM macro of a cache memory bank, the cache memory bank being divided into at least three rows of a plurality of EDRAM macros, the EDRAM macro being associated with one of the at least three rows, iteratively testing each line of the EDRAM macro, the testing including attempting at least one write operation at each line of the EDRAM macro, determining if an error occurred during the testing, and disabling write operations for an entire row of EDRAM macros associated with the EDRAM macro based on the determining.

Abstract: Managing concurrent serialized interrupt broadcast commands in a multi-node, symmetric multiprocessing computer including receiving, by a communications adapter in a compute node, a plurality of serialized interrupt broadcast commands; receiving, by the communications adapter, a plurality of interrupt tags for the plurality of serialized interrupt broadcast commands, each interrupt tag including an identification of an interrupt service order for a serialized interrupt broadcast command; assigning, by the communications adapter, to each serialized interrupt broadcast command its interrupt tag; and if an interrupt tag assigned to a serialized interrupt broadcast command has an interrupt service order that matches a value of a current operation tag that identifies the next serialized interrupt broadcast command to be exposed to the one or more processors, exposing, by the communications adapter, the serialized interrupt broadcast command to the one or more processors on the compute node to be serviced.

Abstract: Systems, methods and computer program products for data buffers partitioned from a cache array. An exemplary embodiment includes a method in a processor and for providing data buffers partitioned from a cache array, the method including clearing cache directories associated with the processor to an initial state, obtaining a selected directory state from a control register preloaded by the service processor, in response to the control register including the desired cache state, sending load commands with an address and data, loading cache lines and cache line directory entries into the cache and storing the specified data in the corresponding cache line.

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 state 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 mechanism for data buffering is provided. A portion of a cache is allocated as buffer regions, and another portion of the cache is designated as random access memory (RAM). One of the buffer regions is assigned to a processor. A data block is stored to the one of the buffer regions of the cache according an instruction of the processor. The data block is stored from the one of the buffer regions of the cache to the memory.

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: A method and apparatus for implementing a combined data/coherency cache for a shared memory multi-processor. The combined data/coherency cache includes a system cache with a number of entries. The method includes building a system cache directory with a number of entries equal to the number of entries of the system cache. The building includes designating a number of sub-entries for each entry which is determined by a number of sub-entries operable for performing system cache coherency functions. The building also includes providing a sub-entry logic designator for each entry, and mapping one of the sub-entries for each entry to the system cache via the sub-entry logic designator.

Abstract: Caching where portions of data are stored in slower main memory and are transferred to faster memory between one or more processors and the main memory. The cache is such that an individual cache system must communicate to other associated cache systems, or check with such cache systems, to determine if they contain a copy of a given cached location prior to or upon modification or appropriation of data at a given cached location. The cache further includes provisions for determining when the data stored in a particular memory location may be replaced.

Abstract: A method and apparatus are disclosed for performing maintenance operations in a system using address, data, and controls which are transported through the system, allowing for parallel and serial operations to co-exist without the parallel operations being slowed down by the serial ones. It also provides for use of common shifters, engines, and protocols as well as efficient conversion of ECC to parity and parity to ECC as needed in the system. The invention also provides for error detection and isolation, both locally and in the reported status. The invention provides for large maintenance address and data spaces (typically 64 bits address and 64 bits data per address supported).

Abstract: Main memory operation in a symmetric multiprocessing computer, the computer comprising one or more processors operatively coupled through a cache controller to at least one cache of main memory, the main memory shared among the processors, the computer further comprising input/output (‘I/O’) resources, including receiving, in the cache controller from an issuing resource, a memory instruction for a memory address, the memory instruction requiring writing data to main memory; locking by the cache controller the memory address against further memory operations for the memory address; advising the issuing resource of completion of the memory instruction before the memory instruction completes in main memory; issuing by the cache controller the memory instruction to main memory; and unlocking the memory address only after completion of the memory instruction in main memory.

Abstract: Tracking dynamic memory de-allocation using a single configuration table having a first register and a second register includes setting the first register as an active register, initiating a de-allocation of desired storage increments from a memory partition, setting the storage increments in the second register as invalid, purging all caches associated with the single configuration table, setting the second register as the active register and the first register as an inactive register, setting the desired storage increments in the first register as invalid, switching the active register from the second register to the first register to complete memory de-allocation using the single configuration table.

Abstract: Managing concurrent serialized interrupt broadcast commands in a multi-node, symmetric multiprocessing computer including receiving, by a communications adapter in a compute node, a plurality of serialized interrupt broadcast commands; receiving, by the communications adapter, a plurality of interrupt tags for the plurality of serialized interrupt broadcast commands, each interrupt tag including an identification of an interrupt service order for a serialized interrupt broadcast command; assigning, by the communications adapter, to each serialized interrupt broadcast command its interrupt tag; and if an interrupt tag assigned to a serialized interrupt broadcast command has an interrupt service order that matches a value of a current operation tag that identifies the next serialized interrupt broadcast command to be exposed to the one or more processors, exposing, by the communications adapter, the serialized interrupt broadcast command to the one or more processors on the compute node to be serviced.

Abstract: A mechanism for data buffering is provided. A portion of a cache is allocated as buffer regions, and another portion of the cache is designated as random access memory (RAM). One of the buffer regions is assigned to a processor. A data block is stored to the one of the buffer regions of the cache according an instruction of the processor. The data block is stored from the one of the buffer regions of the cache to the memory.

Abstract: A system and computer implemented method for isolating errors in a computer system is provided. The method includes receiving a direct memory access (DMA) command to access a computer memory, a read response, or an interrupt; associating the DMA command to access the computer memory, the read response, or the interrupt with a stream identified by a stream identification (ID); detecting a memory error caused by the DMA command in the stream, the memory error resulting in stale data in the computer memory; and isolating the memory error in the stream associated with the stream ID from other streams associated with other stream IDs upon detecting the memory error.

Abstract: Maintaining cache coherence in a multi-node, symmetric multiprocessing computer, the computer composed of a plurality of compute nodes, including, broadcasting upon a cache miss by the first compute node to other compute nodes a request for the cache line; if at least two of the compute nodes has a correct copy of the cache line, selecting which compute node is to transmit the correct copy of the cache line to the first node, and transmitting from the selected compute node to the first node the correct copy of the cache line; and updating by each node the state of the cache line in each node, in dependence upon one or more of the states of the cache line in all the nodes.

Abstract: Embedded dynamic random access memory (EDRAM) macro disablement in a cache memory includes isolating an EDRAM macro of a cache memory bank, the cache memory bank being divided into at least three rows of a plurality of EDRAM macros, the EDRAM macro being associated with one of the at least three rows, iteratively testing each line of the EDRAM macro, the testing including attempting at least one write operation at each line of the EDRAM macro, determining if an error occurred during the testing, and disabling write operations for an entire row of EDRAM macros associated with the EDRAM macro based on the determining.

Abstract: Maintaining cache coherence in a multi-node, symmetric multiprocessing computer, the computer composed of a plurality of compute nodes, including, broadcasting upon a cache miss by a first compute node a request for a cache line; transmitting from each of the other compute nodes to all other nodes the state of the cache line on that node, including transmitting from any compute node having a correct copy to the first node the correct copy of the cache line; and updating by each node the state of the cache line in each node, in dependence upon one or more of the states of the cache line in all the nodes.