Abstract: Statistical data is used to enable or disable snooping on a bus of a processor. A command is received via a first bus or a second bus communicably coupling processor cores and caches of chiplets on the processor. Cache logic on a chiplet determines whether or not a local cache on the chiplet can satisfy a request for data specified in the command. In response to determining that the local cache can satisfy the request for data, the cache logic updates statistical data maintained on the chiplet. The statistical data indicates a probability that the local cache can satisfy a future request for data. Based at least in part on the statistical data, the cache logic determines whether to enable or disable snooping on the second bus by the local cache.

Abstract: In response to receipt of a store-conditional (STCX) request of a processor core, the STCX request is buffered in an entry of a store queue for eventual service by a read-claim (RC) machine by reference to a cache array, and the STCX request is concurrently transmitted via a bypass path bypassing the store queue. In response to dispatch logic dispatching the STCX request transmitted via the bypass path to the RC machine for service by reference to the cache array, the entry of the STCX request in the store queue is updated to prohibit selection of the STCX request in the store queue for service. In response to the STCX request transmitted via the bypass path not being dispatched by the dispatch logic, the STCX is thereafter transmitted from the store queue to the dispatch logic and dispatched to the RC machine for service by reference to the cache array.

Abstract: In response to receipt of a store-conditional (STCX) request of a processor core, the STCX request is buffered in an entry of a store queue for eventual service by a read-claim (RC) machine by reference to a cache array, and the STCX request is concurrently transmitted via a bypass path bypassing the store queue. In response to dispatch logic dispatching the STCX request transmitted via the bypass path to the RC machine for service by reference to the cache array, the entry of the STCX request in the store queue is updated to prohibit selection of the STCX request in the store queue for service. In response to the STCX request transmitted via the bypass path not being dispatched by the dispatch logic, the STCX is thereafter transmitted from the store queue to the dispatch logic and dispatched to the RC machine for service by reference to the cache array.

Abstract: A technique for operating a data processing system includes determining whether a cache line that is to be victimized from a cache includes high availability (HA) data that has not been logged. In response determining that the cache line that is to be victimized from the cache includes HA data that has not been logged, an address for the HA data is written to an HA dirty address data structure, e.g., a dirty address table (DAT), in a first memory via a first non-blocking channel. The cache line that is victimized from the cache is written to a second memory via a second non-blocking channel.

Abstract: A technique for operating a data processing system includes determining whether a cache line that is to be victimized from a cache includes high availability (HA) data that has not been logged. In response determining that the cache line that is to be victimized from the cache includes HA data that has not been logged, an address for the HA data is written to an HA dirty address data structure, e.g., a dirty address table (DAT), in a first memory via a first non-blocking channel. The cache line that is victimized from the cache is written to a second memory via a second non-blocking channel.

Abstract: A technique for operating a high-availability (HA) data processing system includes, in response to receiving an HA logout indication at a cache, initiating a walk of the cache to locate cache lines in the cache that include HA data. In response to determining that a cache line includes HA data, an address of the cache line is logged in a first portion of a buffer in the cache. In response to the first portion of the buffer reaching a determined fill level, contents of the first portion of the buffer are logged to another memory. In response to all cache lines in the cache being walked, the cache walk is terminated.

Abstract: A technique for operating a high-availability (HA) data processing system includes, in response to receiving an HA logout indication at a cache, initiating a walk of the cache to locate cache lines in the cache that include HA data. In response to determining that a cache line includes HA data, an address of the cache line is logged in a first portion of a buffer in the cache. In response to the first portion of the buffer reaching a determined fill level, contents of the first portion of the buffer are logged to another memory. In response to all cache lines in the cache being walked, the cache walk is terminated.

Abstract: A multiprocessor data processing system includes a plurality of cache memories including a cache memory. The cache memory issues a read-type operation for a target cache line. While waiting for receipt of the target cache line, the cache memory monitors to detect a competing store-type operation for the target cache line. In response to receiving the target cache line, the cache memory installs the target cache line in the cache memory, and sets a coherency state of the target cache line installed in the cache memory based on whether the competing store-type operation is detected.

Abstract: A multiprocessor data processing system includes a plurality of cache memories including a cache memory. The cache memory issues a read-type operation for a target cache line. While waiting for receipt of the target cache line, the cache memory monitors to detect a competing store-type operation for the target cache line. In response to receiving the target cache line, the cache memory installs the target cache line in the cache memory, and sets a coherency state of the target cache line installed in the cache memory based on whether the competing store-type operation is detected.

Abstract: A multiprocessor data processing system includes a plurality of cache memories including a cache memory. The cache memory issues a read-type operation for a target cache line. While waiting for receipt of the target cache line, the cache memory monitors to detect a competing store-type operation for the target cache line. In response to receiving the target cache line, the cache memory installs the target cache line in the cache memory, and sets a coherency state of the target cache line installed in the cache memory based on whether the competing store-type operation is detected.

Abstract: A method and processor chip design for enabling a processor core to continue sending store operations speculatively to the store queue after the core receives indication that the store queue is full. The processor core is configured with speculative store logic that enables the processor core to continue issuing store operations while the store queue full signal is asserted. A copy of the speculatively issued store operation is placed within a speculative store buffer. The core waits for a signal from the store queue indicating the store operation was accepted into the store queue. When the speculatively-issued store operation is accepted within the store queue, the copy is discarded from the buffer. However, when the store operation is rejected, the speculative store logic re-issues the store operation ahead of normal store operations.

Abstract: A technique for triggering a system bus write command with user code includes identifying a specific store-type instruction in a user instruction sequence. The specific store-type instruction is converted into a specific request-type command, which is configured to include core permission controls (that are stored in core configuration registers of a processor core by a trusted kernel) and user created data (stored in a cache memory). Slave devices are configured through register space (that is only accessible by the trusted kernel) with respective slave permission controls. The specific request-type command is then transmitted from the cache memory, via a system bus. In this case, the slave devices that receive the specific request-type command process the specific request-type command when the core permission controls are the same as the respective slave permission controls. The trusted kernel may be included in a hypervisor or an operating system.

Abstract: An information handling system (IHS) includes a processor with a cache memory system. The processor includes a processor core with an L1 cache memory that couples to an L2 cache memory. The processor includes an arbitration mechanism that controls load and store requests to the L2 cache memory. The arbitration mechanism includes control logic that enables a load request to interrupt a store request that the L2 cache memory is currently servicing. The L2 cache memory includes dual data banks so that one bank may perform a load operation while the other bank performs a store operation. The cache system provides dual dispatch points into the data flow to the dual cache banks of the L2 cache memory.

Abstract: A computer implemented method, a processor chip, a data processing system, and computer program product in a data processing system process information in a store cache of a data processing system. The store cache receives a first entry that includes a first address indicating a first segment of a cache line. The store cache then receives a second entry including a second address indicating a second segment of the cache line. Responsive to the first segment not being equal to the second segment, the first entry is chained to the second entry.

Abstract: An information handling system (IHS) includes a processor with a cache memory system. The processor includes a processor core with an L1 cache memory that couples to an L2 cache memory. The processor includes an arbitration mechanism that controls load and store requests to the L2 cache memory. The arbitration mechanism includes control logic that enables a load request to interrupt a store request that the L2 cache memory is currently servicing. The L2 cache memory includes dual data banks so that one bank may perform a load operation while the other bank performs a store operation. The cache system provides a single dispatch point into the data flow to the dual cache banks of the L2 cache memory.

Abstract: A processing unit for a data processing system includes a processor core having one or more execution units for processing instructions and a register file for storing data accessed in processing of the instructions. The processing unit also includes a multi-level cache hierarchy coupled to and supporting the processor core. The multi-level cache hierarchy includes at least one upper level of cache memory having a lower access latency and at least one lower level of cache memory having a higher access latency. The lower level of cache memory, responsive to receipt of a memory access request that hits only a partial cache line in the lower level cache memory, sources the partial cache line to the at least one upper level cache memory to service the memory access request. The at least one upper level cache memory services the memory access request without caching the partial cache line.

Abstract: A processor includes at least one instruction execution unit that executes store instructions to obtain store operations and a store queue coupled to the instruction execution unit. The store queue includes a queue entry in which the store queue gathers multiple store operations during a store gathering window to obtain a data portion of a write transaction directed to lower level memory. In addition, the store queue includes dispatch logic that varies a size of the store gathering window to optimize store performance for different store behaviors and workloads.

Abstract: An information handling system (IHS) includes a processor with a cache memory system. The processor includes a processor core with an L1 cache memory that couples to an L2 cache memory. The processor includes an arbitration mechanism that controls load and store requests to the L2 cache memory. The arbitration mechanism includes control logic that enables a load request to interrupt a store request that the L2 cache memory is currently servicing. The L2 cache memory includes dual data banks so that one bank may perform a load operation while the other bank performs a store operation. The cache system provides dual dispatch points into the data flow to the dual cache banks of the L2 cache memory.

Abstract: An information handling system (IHS) includes a processor with a cache memory system. The processor includes a processor core with an L1 cache memory that couples to an L2 cache memory. The processor includes an arbitration mechanism that controls load and store requests to the L2 cache memory. The arbitration mechanism includes control logic that enables a load request to interrupt a store request that the L2 cache memory is currently servicing. The L2 cache memory includes dual data banks so that one bank may perform a load operation while the other bank performs a store operation. The cache system provides a single dispatch point into the data flow to the dual cache banks of the L2 cache memory.

Abstract: A processing unit for a data processing system includes a processor core having one or more execution units for processing instructions and a register file for storing data accessed in processing of the instructions. The processing unit also includes a multi-level cache hierarchy coupled to and supporting the processor core. The multi-level cache hierarchy includes at least one upper level of cache memory having a lower access latency and at least one lower level of cache memory having a higher access latency. The lower level of cache memory, responsive to receipt of a memory access request that hits only a partial cache line in the lower level cache memory, sources the partial cache line to the at least one upper level cache memory to service the memory access request. The at least one upper level cache memory services the memory access request without caching the partial cache line.