Abstract: Techniques for handling queuing of memory accesses prevent passing excessive requests that implicate a region of memory subject to a high latency memory operation, such as a memory refresh operation, memory scrubbing or an internal bus calibration event, to a re-order queue of a memory controller. The memory controller includes a queue for storing pending memory access requests, a re-order queue for receiving the requests, and a control logic implementing a queue controller that determines if there is a collision between a received request and an ongoing high-latency memory operation. If there is a collision, then transfer of the request to the re-order queue may be rejected outright, or a count of existing queued operations that collide with the high latency operation may be used to determine if queuing the new request will exceed a threshold number of such operations.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation operation in response to detecting a barrier instruction in the instruction sequence immediately preceding the store instruction in program order and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation in response to detecting a barrier instruction in the instruction sequence immediately preceding the store instruction in program order and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: According to a method of data processing, a memory controller receives a plurality of data prefetch requests from multiple processor cores in the data processing system, where the plurality of prefetch load requests include a data prefetch request issued by a particular processor core among the multiple processor cores. In response to receipt of the data prefetch request, the memory controller provides a coherency response indicating an excess number of data prefetch requests. In response to the coherency response, the particular processor core reduces a rate of issuance of data prefetch requests.

Abstract: A data structure includes a plurality of entries each corresponding to a different systemwide combined response of a data processing system. A particular entry includes identifiers of multiple possible actions that can be taken in response to a systemwide combined response. Master logic issues a memory access request on a system fabric of the data processing system. The master logic, responsive to receiving the systemwide combined response and a selection of one of the multiple possible actions from a source of the memory access request prior to receipt of the systemwide combined response, selects the particular entry based on the systemwide combined response and selects one of the multiple possible actions identified in the particular entry based on the received selection. The master logic services the memory access request in accordance with the systemwide combined response by performing the selected one of the multiple possible actions.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation operation in response to detecting, in the instruction sequence, a barrier instruction that precedes the store instruction in program order and that includes a field set to indicate the store operation should be accorded high priority and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates one or more store operations by executing one or more store instructions in an instruction sequence. The one or more store operations are marked as a high priority store operations in response to detecting, in the instruction sequence, a window opening instruction and a window closing instruction bounding the one or more store instructions and are not so marked otherwise. The one or more store operations are buffered in a store queue associated with a cache memory of the processor core. Handling of the one or more store operations in the store queue is expedited in response to the one or more store operations being marked as high priority store operations and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation operation in response to detecting a barrier instruction in the instruction sequence immediately preceding the store instruction in program order and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation operation in response to detecting a barrier instruction in the instruction sequence immediately preceding the store instruction in program order and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation in response to the store instruction being marked as high priority and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation operation in response to detecting, in the instruction sequence, a barrier instruction that precedes the store instruction in program order and that includes a field set to indicate the store operation should be accorded high priority and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates one or more store operations by executing one or more store instructions in an instruction sequence. The one or more store operations are marked as a high priority store operations in response to detecting, in the instruction sequence, a window opening instruction and a window closing instruction bounding the one or more store instructions and are not so marked otherwise. The one or more store operations are buffered in a store queue associated with a cache memory of the processor core. Handling of the one or more store operations in the store queue is expedited in response to the one or more store operations being marked as high priority store operations and not expedited otherwise.

Abstract: In at least some embodiments, a processor core generates a store operation by executing a store instruction in an instruction sequence. The store operation is marked as a high priority store operation in response to the store instruction being marked as high priority and is not so marked otherwise. The store operation is buffered in a store queue associated with a cache memory of the processor core. Handling of the store operation in the store queue is expedited in response to the store operation being marked as a high priority store operation and not expedited otherwise.

Abstract: A request to send a message from a first component, located on a first processor, to a second component, located on a second processor, is received. It is determined that the second processor can be communicated with via a first bidirectional communication path. It is determined that bandwidth is available on the first bidirectional communication path. It is determined that bandwidth is available on a second bidirectional communication path. In response to a determination that bandwidth is available on the second bidirectional communication path, a data path is created between the first component and the second bidirectional communication path and the request to send the message to the second component is granted. In response to a determination that bandwidth is not available on the first bidirectional communication path or on the second bidirectional communication path, the grant of the request to send the message to the second component is delayed.

Abstract: A processor core of a data processing system receives a push instruction of a sending thread that requests that a message payload identified by at least one operand of the push instruction be pushed to a mailbox of a receiving thread. In response to receiving the push instruction, the processor core executes the push instruction of the sending thread. In response to executing the push instruction, the processor core initiates transmission of the message payload to the mailbox of the receiving thread. In one embodiment, the processor core initiates transmission of the message payload by transmitting a co-processor request to a switch of the data processing system via an interconnect fabric.

Abstract: A processor core of a data processing system receives a push instruction of a sending thread that requests that a message payload identified by at least one operand of the push instruction be pushed to a mailbox of a receiving thread. In response to receiving the push instruction, the processor core executes the push instruction of the sending thread. In response to executing the push instruction, the processor core initiates transmission of the message payload to the mailbox of the receiving thread. In one embodiment, the processor core initiates transmission of the message payload by transmitting a co-processor request to a switch of the data processing system via an interconnect fabric.

Abstract: A request to send a first message from a first component to a second component is received at an arbiter. The first component is located in a first time zone and the second component is located in a second time zone. The arbiter determines that the second component is located in the second time zone. It is determined that the second time zone can be communicated with via one or more communications channels in a first direction. It is determined whether bandwidth is available on the one or more communications channels in the first direction. If bandwidth is available on the one or more communications channels in the first direction, a data path between the first component and the one or more communications channels in the first direction is created and the request is granted. Otherwise, the grant of the request is delayed.

Abstract: A request to send a first message from a first component to a second component is received at an arbiter. The first component is located in a first time zone and the second component is located in a second time zone. The arbiter determines that the second component is located in the second time zone. It is determined that the second time zone can be communicated with via one or more communications channels in a first direction. It is determined whether bandwidth is available on the one or more communications channels in the first direction. If bandwidth is available on the one or more communications channels in the first direction, a data path between the first component and the one or more communications channels in the first direction is created and the request is granted. Otherwise, the grant of the request is delayed.

Abstract: A data structure includes a plurality of entries each corresponding to a different systemwide combined response of a data processing system. A particular entry includes identifiers of multiple possible actions that can be taken in response to a systemwide combined response. Master logic issues a memory access request on a system fabric of the data processing system. The master logic, responsive to receiving the systemwide combined response and a selection of one of the multiple possible actions from a source of the memory access request prior to receipt of the systemwide combined response, selects the particular entry based on the systemwide combined response and selects one of the multiple possible actions identified in the particular entry based on the received selection. The master logic services the memory access request in accordance with the systemwide combined response by performing the selected one of the multiple possible actions.

Abstract: A technique for operating a memory system for a node includes interrogating, by a cache, an associated cache directory to determine whether a shared cache line to be installed in the cache is associated with an invalid global state in the cache. The invalid global state specifies that a version of the shared cache line has been intervened off-node. In response to the shared cache line being in the invalid global state the cache spawns a castout invalid global command for the shared cache line. The shared cache line is installed in the cache. A coherence state for the shared cache line is updated in the associated cache directory to indicate the shared cache line is shared.