Abstract: Embodiments are for processor cross-core cache line contention management. A computer-implemented method includes sending a cross-invalidate command to one or more caches based on receiving a cache state change request for a cache line in a symmetric multiprocessing system and determining a retry delay based on receiving a cross-invalidate reject response from at least one of the one or more caches. The computer-implemented method also includes waiting until a retry delay period associated with the retry delay has elapsed to resend the cross-invalidate command to the one or more caches and granting the cache state change request for the cache line based on receiving a cross-invalidate accept response from the one or more caches.

Abstract: A lower-level cache managing cross-core invalidation (XI) snapshots in a shared-memory multiprocessing system, wherein the management of XI snapshots reduces an amount of required snapshots while allowing shared lower-level caches, comprising: the lower-level cache maintaining respective response sync state for at least one processor in a plurality of processors signifying that a line may have been changed by another processor since last fetched by a requesting processor.

Abstract: Serialized broadcast command messaging in a distributed symmetric multiprocessing (SMP) system, including: sending a serial broadcast command from a home chip to a plurality of other chips comprising serial primary chip, wherein each chip of the plurality of other chips comprises a broadcast controller mapped to a home chip broadcast controller; assigning, by the serial primary chip, a tag to the serial broadcast command; sending, from the serial primary chip, to the home chip and a remainder of the plurality of other chips, the tag; and broadcasting, by the home chip and each chip of the plurality of other chips, the serial broadcast command in an order based on the tag of the serial broadcast command.

Abstract: A computer-implemented method is provided. The method includes determining whether a rejection of a request is required and determining whether the request is software forward progress (SFP)-likely or SFP-unlikely upon determining that the rejection of the request is required. The method also includes executing a first pseudo random decision to set or not set a requested state of the request in an event the request is SFP-likely or SFP-unlikely, respectively, and rejecting the request following execution of the second pseudo random decision.

Abstract: To facilitate an efficient processing of contended cache lines, a cache controller that is associated with a requestor receives a fetch request for data from the requestor. The fetch request is associated with a cache scope designation. If the data is in a high-level cache (e.g., L1 cache) associated with the requestor, the cache controller returns the requested data to the requestor. If the data is not in the high-level cache or if the data is not within the cache pool identified by the cache scope of search designation, and/or if obtaining the data is contentious, the controller returns a cache miss, undeliverable data, and request done instruction to the requestor. Such scheme allows or permits address contention events when the requestor deems such events are necessary and/or when important. As such, address contention events, performance, latencies, increased executions times, inefficient use of resources, may be diminished.

Abstract: Computation, placement, and accessing of error correcting codes (ECC) in a computer system data cache enabling partial reads and writes to each line of data in the cache. For storing multiple compressed blocks, received at differing time periods, in a single cache line, the ECC for the first compressed block is stored in the ECC field of the cache and the ECC for the second and subsequently received compressed blocks is appended to the compressed data. Additionally, an auxiliary ECC cache may be constructed for temporarily holding a partial ECC for a partial read/write, and a new ECC for the partial read/write is computed using the partial ECC.

Abstract: To facilitate an efficient processing of contended cache lines, a cache controller that is associated with a requestor receives a fetch request for data from the requestor. The fetch request is associated with a cache scope designation. If the data is in a high-level cache (e.g., L1 cache) associated with the requestor, the cache controller returns the requested data to the requestor. If the data is not in the high-level cache or if the data is not within the cache pool identified by the cache scope of search designation, and/or if obtaining the data is contentious, the controller returns a cache miss, undeliverable data, and request done instruction to the requestor. Such scheme allows or permits address contention events when the requestor deems such events are necessary and/or when important. As such, address contention events, performance, latencies, increased executions times, inefficient use of resources, may be diminished.

Abstract: A multi-purpose server cache directory in a computing environment is provided. One of a plurality of operation modes may be selectively enabled or disabled, by a cache directory, based on a computation phase, data type, and data pattern for caching data in a cache having a plurality of address tags in the cache directory greater than a number of data lines in a cache array.

Abstract: A method and a computer system for core recovery management are provided. A first operation signal is generated via a first hardware agent. The first operation signal indicates that the first hardware agent is processing an operation requested by a first processor core. The first processor core receives a first extend fence signal based on the generated first operation signal. As long as the first extend fence signal is received via the first processor core, the first processor core is kept in a fenced state for core recovery.

Abstract: A computer-implemented method is provided. The method includes determining whether a rejection of a request is required and determining whether the request is software forward progress (SFP)-likely or SFP-unlikely upon determining that the rejection of the request is required. The method also includes executing a first pseudo random decision to set or not set a requested state of the request in an event the request is SFP-likely or SFP-unlikely, respectively, and rejecting the request following execution of the second pseudo random decision.

Abstract: A central processing unit (CPU) system including a CPU core can include an adaptive cache compressor, which is capable of monitoring a miss profile of a cache. The adaptive cache compressor can compare the miss profile to a miss threshold. Based on this comparison, the adaptive cache compressor can determine whether to enable compression of the cache.

Abstract: A computer system includes a processor core and a memory system in signal communication with the processor core. The memory system includes a first cache and a second cache. The first cache is arranged at a first level of a hierarchy in the memory system and is configured to store a plurality of first-cache entries. The second cache is arranged at a second level of the hierarchy that is lower than the first level, and stores a plurality of second-cache entries. The first cache maintains a directory that contains information for each of the first-cache entries. The second cache maintains a shadow pointer directory (SPD) that includes one or more SPD entries that maps each of the first-cache entries to a corresponding second cache entry at a lower-level cache location.

Abstract: A cache compression predictor can be coupled to a central processing unit (CPU) CPU core. The CPU core can read a cache line from a cache. Upon the CPU core reading the cache line, the cache compression predictor can predict whether the cache line is a compressed cache line or an uncompressed cache line.

Abstract: Computation, placement, and accessing of error correcting codes (ECC) in a computer system data cache enabling partial reads and writes to each line of data in the cache. For storing multiple compressed blocks, received at differing time periods, in a single cache line, the ECC for the first compressed block is stored in the ECC field of the cache and the ECC for the second and subsequently received compressed blocks is appended to the compressed data. Additionally, an auxiliary ECC cache may be constructed for temporarily holding a partial ECC for a partial read/write, and a new ECC for the partial read/write is computed using the partial ECC.

Abstract: Embodiments are for special tracking pool enhancement for core L1 address invalidates. An invalidate request is designated to fill an entry in a queue in a local cache of a processor core, the queue including a first allocation associated with processing any type of invalidate request and a second allocation associated with processing an invalidate request not requiring a response in order for a controller to be made available, the entry being in the second allocation. Responsive to designating the invalidate request to fill the entry in the queue in the local cache, a state of the controller that made the invalidate request is changed to available based at least in part on the entry being in the second allocation.

Abstract: Embodiments are for special tracking pool enhancement for core L1 address invalidates. An invalidate request is designated to fill an entry in a queue in a local cache of a processor core, the queue including a first allocation associated with processing any type of invalidate request and a second allocation associated with processing an invalidate request not requiring a response in order for a controller to be made available, the entry being in the second allocation. Responsive to designating the invalidate request to fill the entry in the queue in the local cache, a state of the controller that made the invalidate request is changed to available based at least in part on the entry being in the second allocation.

Abstract: Aspects of the invention include computer-implemented methods, systems, and computer program products that assign a centralized event tag to each communication interface of a plurality of communication interfaces of a chip interconnected in a hierarchy through the communication interfaces to a plurality of chips in a multiprocessing system. A determination is performed of whether to accept or drop a message associated with an event received at one of the communication interfaces of the chip based on comparing a local centralized event tag with a received centralized event tag. The local centralized event tag is updated based on one or more advancing rules to maintain event synchronization between the chip and the plurality of chips.

Abstract: A multi-purpose server cache directory in a computing environment is provided. One of a plurality of operation modes may be selectively enabled or disabled, by a cache directory, based on a computation phase, data type, and data pattern for caching data in a cache having a plurality of address tags in the cache directory greater than a number of data lines in a cache array.

Abstract: Aspects of the invention include computer-implemented methods, systems, and computer program products that assign a centralized event tag to each communication interface of a plurality of communication interfaces of a chip interconnected in a hierarchy through the communication interfaces to a plurality of chips in a multiprocessing system. A determination is performed of whether to accept or drop a message associated with an event received at one of the communication interfaces of the chip based on comparing a local centralized event tag with a received centralized event tag. The local centralized event tag is updated based on one or more advancing rules to maintain event synchronization between the chip and the plurality of chips.

Abstract: Low latency in a non-uniform cache access (“NUCA”) cache in a computing environment is provided. A first compressed cache line is interleaved with a second compressed cache line into a single cache line of the NUCA cache, where data of the first compressed cache line is stored in one or more even sectors in the single cache line and stored in zero or more odd sectors in the single cache line after the data fills the one or more even sectors, and data of the second compressed cache line is stored in the one or more odd sectors in the single cache line and stored in zero or more even sectors in the single cache line after the data fills the one or more odd sectors.