Abstract: Embodiments of the present invention are directed to managing a shared high-level cache for dual clusters of fully connected integrated circuit multiprocessors. An example of a computer-implemented method includes: providing a drawer comprising a plurality of clusters, each of the plurality of clusters comprising a plurality of processors; providing a shared cache integrated circuit to manage a shared cache memory among the plurality of clusters; receiving, by the shared cache integrated circuit, an operation of one of a plurality of operation types from one of the plurality of processors; and processing, by the shared cache integrated circuit, the operation based at least in part on the operation type of the operation according to a set of rules for processing the operation type.

Abstract: Embodiments of the present invention are directed to managing a shared high-level cache for dual clusters of fully connected integrated circuit multiprocessors. An example of a computer-implemented method includes: providing a drawer comprising a plurality of clusters, each of the plurality of clusters comprising a plurality of processors; providing a shared cache integrated circuit to manage a shared cache memory among the plurality of clusters; receiving, by the shared cache integrated circuit, an operation of one of a plurality of operation types from one of the plurality of processors; and processing, by the shared cache integrated circuit, the operation based at least in part on the operation type of the operation according to a set of rules for processing the operation type.

Abstract: A cache coherency management facility to reduce latency in granting exclusive access to a cache in certain situations. A node requests exclusive access to a cache line of the cache. The node is in one region of nodes of a plurality of regions of nodes. The one region of nodes includes the node requesting exclusive access and another node of the computing environment, in which the node and the another node are local to one another as defined by a predetermined criteria. The node requesting exclusive access checks a locality cache coherency state of the another node, the locality cache coherency state being specific to the another node and indicating whether the another node has access to the cache line. Based on the checking indicating that the another node has access to the cache line, a determination is made that the node requesting exclusive access is to be granted exclusive access to the cache line.

Abstract: Embodiments of the present invention are directed to hot cache line arbitration. An example of a computer-implemented method for hot cache line arbitration includes receiving a request for exclusive access to a cache line from a requestor of a drawer in a processing system. The method further includes bringing the cache line to a local cache of the drawer. The method further includes invalidating copies of the cache line in the processing system. The method further includes loading a remote fetch address register (RFAR) controller on other drawers in the processing system, wherein the RFAR comprises a local pending flag and a remote pending flag.

Abstract: Embodiments of the present invention are directed to a computer-implemented method for ownership tracking updates across multiple simultaneous operations. A non-limiting example of the computer-implemented method includes receiving, by a cache directory control circuit, a message to update a cache directory entry. The method further includes, in response, updating, by the cache directory control circuit, the cache directory entry, and generating a reverse compare signal including an updated ownership vector of a memory line corresponding to the cache directory entry. The method further includes sending the reverse compare signal to a cache controller associated with the cache directory entry.

Abstract: Embodiments of the present invention are directed to a computer-implemented method for ownership tracking updates across multiple simultaneous operations. A non-limiting example of the computer-implemented method includes receiving, by a cache directory control circuit, a message to update a cache directory entry. The method further includes, in response, updating, by the cache directory control circuit, the cache directory entry, and generating a reverse compare signal including an updated ownership vector of a memory line corresponding to the cache directory entry. The method further includes sending the reverse compare signal to a cache controller associated with the cache directory entry.

Abstract: Embodiments include methods, systems and computer program products method for maintaining ordered memory access with parallel access data streams associated with a distributed shared memory system. The computer-implemented method includes performing, by a first cache, a key check, the key check being associated with a first ordered data store. A first memory node signals that the first memory node is ready to begin pipelining of a second ordered data store into the first memory node to an input/output (I/O) controller. A second cache returns a key response to the first cache indicating that the pipelining of the second ordered data store can proceed. The first memory node sends a ready signal indicating that the first memory node is ready to continue pipelining of the second ordered data store into the first memory node to the I/O controller, wherein the ready signal is triggered by receipt of the key response.

Abstract: Embodiments of the present invention are directed to hot cache line arbitration. An example of a computer-implemented method for hot cache line arbitration includes detecting, by a processing device, a hot cache line scenario. The computer-implemented method further includes tracking, by the processing device, hot cache line requests from requesters to determine subsequent satisfaction of the requests. The computer-implemented method further includes facilitating, by the processing device, servicing of the requests according to hierarchy of the requestors.

Abstract: Embodiments include methods, systems and computer program products method for maintaining ordered memory access with parallel access data streams associated with a distributed shared memory system. The computer-implemented method includes performing, by a first cache, a key check, the key check being associated with a first ordered data store. A first memory node signals that the first memory node is ready to begin pipelining of a second ordered data store into the first memory node to an input/output (I/O) controller. A second cache returns a key response to the first cache indicating that the pipelining of the second ordered data store can proceed. The first memory node sends a ready signal indicating that the first memory node is ready to continue pipelining of the second ordered data store into the first memory node to the I/O controller, wherein the ready signal is triggered by receipt of the key response.

Abstract: Embodiments of the present invention are directed to managing a shared high-level cache for dual clusters of fully connected integrated circuit multiprocessors. An example of a computer-implemented method includes: providing a drawer comprising a plurality of clusters, each of the plurality of clusters comprising a plurality of processors; providing a shared cache integrated circuit to manage a shared cache memory among the plurality of clusters; receiving, by the shared cache integrated circuit, an operation of one of a plurality of operation types from one of the plurality of processors; and processing, by the shared cache integrated circuit, the operation based at least in part on the operation type of the operation according to a set of rules for processing the operation type.

Abstract: Embodiments of the present invention are directed to managing a shared high-level cache for dual clusters of fully connected integrated circuit multiprocessors. An example of a computer-implemented method includes: providing a drawer comprising a plurality of clusters, each of the plurality of clusters comprising a plurality of processors; providing a shared cache integrated circuit to manage a shared cache memory among the plurality of clusters; receiving, by the shared cache integrated circuit, an operation of one of a plurality of operation types from one of the plurality of processors; and processing, by the shared cache integrated circuit, the operation based at least in part on the operation type of the operation according to a set of rules for processing the operation type.

Abstract: Embodiments of the present invention are directed to a computer-implemented method for ownership tracking updates across multiple simultaneous operations. A non-limiting example of the computer-implemented method includes receiving, by a cache directory control circuit, a message to update a cache directory entry. The method further includes, in response, updating, by the cache directory control circuit, the cache directory entry, and generating a reverse compare signal including an updated ownership vector of a memory line corresponding to the cache directory entry. The method further includes sending the reverse compare signal to a cache controller associated with the cache directory entry.

Abstract: Embodiments of the present invention are directed to a computer-implemented method for ownership tracking updates across multiple simultaneous operations. A non-limiting example of the computer-implemented method includes receiving, by a cache directory control circuit, a message to update a cache directory entry. The method further includes, in response, updating, by the cache directory control circuit, the cache directory entry, and generating a reverse compare signal including an updated ownership vector of a memory line corresponding to the cache directory entry. The method further includes sending the reverse compare signal to a cache controller associated with the cache directory entry.

Abstract: Embodiments of the present invention are directed to hot cache line arbitration. An example of a computer-implemented method for hot cache line arbitration includes receiving a request for exclusive access to a cache line from a requestor of a drawer in a processing system. The method further includes bringing the cache line to a local cache of the drawer. The method further includes invalidating copies of the cache line in the processing system. The method further includes loading a remote fetch address register (RFAR) controller on other drawers in the processing system, wherein the RFAR comprises a local pending flag and a remote pending flag.

Abstract: Embodiments of the present invention are directed to hot cache line arbitration. An example of a computer-implemented method for hot cache line arbitration includes detecting, by a processing device, a hot cache line scenario. The computer-implemented method further includes tracking, by the processing device, hot cache line requests from requesters to determine subsequent satisfaction of the requests. The computer-implemented method further includes facilitating, by the processing device, servicing of the requests according to hierarchy of the requestors.

Abstract: A cache coherency management facility to reduce latency in granting exclusive access to a cache in certain situations. A node requests exclusive access to a cache line of the cache. The node is in one region of nodes of a plurality of regions of nodes. The one region of nodes includes the node requesting exclusive access and another node of the computing environment, in which the node and the another node are local to one another as defined by a predetermined criteria. The node requesting exclusive access checks a locality cache coherency state of the another node, the locality cache coherency state being specific to the another node and indicating whether the another node has access to the cache line. Based on the checking indicating that the another node has access to the cache line, a determination is made that the node requesting exclusive access is to be granted exclusive access to the cache line.

Abstract: A cache coherency management facility to reduce latency in granting exclusive access to a cache in certain situations. A node requests exclusive access to a cache line of the cache. The node is in one region of nodes of a plurality of regions of nodes. The one region of nodes includes the node requesting exclusive access and another node of the computing environment, in which the node and the another node are local to one another as defined by a predetermined criteria. The node requesting exclusive access checks a locality cache coherency state of the another node, the locality cache coherency state being specific to the another node and indicating whether the another node has access to the cache line. Based on the checking indicating that the another node has access to the cache line, a determination is made that the node requesting exclusive access is to be granted exclusive access to the cache line.

Abstract: A cache coherency management facility to reduce latency in granting exclusive access to a cache in certain situations. A node requests exclusive access to a cache line of the cache. The node is in one region of nodes of a plurality of regions of nodes. The one region of nodes includes the node requesting exclusive access and another node of the computing environment, in which the node and the another node are local to one another as defined by a predetermined criteria. The node requesting exclusive access checks a locality cache coherency state of the another node, the locality cache coherency state being specific to the another node and indicating whether the another node has access to the cache line. Based on the checking indicating that the another node has access to the cache line, a determination is made that the node requesting exclusive access is to be granted exclusive access to the cache line.

Abstract: In one embodiment, a computer-implemented method includes detecting a cache miss for a cache line. A resource is reserved on each of one or more remote computing nodes, responsive to the cache miss. A request for a state of the cache line on the one or more remote computing nodes is broadcast to the one or more remote computing nodes, responsive to the cache miss. A resource credit is received from a first remote computing node of the one or more remote computing nodes, responsive to the request. The resource credit indicates that the first remote computing node will not participate in completing the request. The resource on the first remote computing node is released, responsive to receiving the resource credit from the first remote computing node.

Abstract: Embodiments relate to reestablishing synchronization across multiple channels in a memory system. One aspect is a computer implemented method that includes receiving an out-of-synchronization indication associated with at least one of a plurality of channels in the memory system. A memory control unit in communication with the channels performs a first stage of reestablishing synchronization that includes selectively stopping new traffic on the plurality of channels, waiting for a first time period to expire, resuming traffic on the plurality of channels based on the first time period expiring, and verifying that synchronization is reestablished for a second time period.