A directory processing method and apparatus are provided to resolve a problem that a directory occupies a relatively large quantity of caches in an existing directory processing solution. The method includes: receiving, by a first data node, a first request sent by a second data node; searching for, by the first data node, a matched directory entry in a directory of the first data node based on tag information and index information in a first physical address; creating, when no matched directory entry is found, a first directory entry of the directory based on the first request, where the first directory entry includes the tag information, first indication information, first pointer information, and first status information, the first pointer information is used to indicate that data in the memory address corresponding to the indication bit that is set to valid is read by the second data node.

A system includes a plurality of host processors and a plurality of HMC devices configured as a distributed shared memory for the host processors. An HMC device includes a plurality of integrated circuit memory die including at least a first memory die arranged on top of a second memory die and at least a portion of the memory of the memory die is mapped to include at least a portion of a memory coherence directory; and a logic base die including at least one memory controller configured to manage three-dimensional (3D) access to memory of the plurality of memory die by at least one second device, and logic circuitry configured to determine memory coherence state information for data stored in the memory of the plurality of memory die, communicate information regarding the access to memory, and include the memory coherence information in the communicated information.

In general, embodiments of the invention relate managing the interaction of applications with one or more file systems and/or data managed by the file systems. More specifically, embodiments of the invention relate to providing applications with access to an overlay file system (OFS) and then servicing OFS operations using a file system module and one or more underlay file systems (UFSes) that are not directly accessible to the applications.

Examples described herein relate to processor circuitry to issue a cache coherence message to a central processing unit (CPU) cluster by selection of a target cluster and issuance of the request to the target cluster, wherein the target cluster comprises the cluster or the target cluster is directly connected to the cluster. In some examples, the selected target cluster is associated with a minimum number of die boundary traversals. In some examples, the processor circuitry is to read an address range for the cluster to identify the target cluster using a single range check over memory regions including local and remote clusters. In some examples, issuance of the cache coherence message to a cluster is to cause the cache coherence message to traverse one or more die interconnections to reach the target cluster.

Systems, apparatuses, and methods for implementing a speculative probe mechanism are disclosed. A system includes at least multiple processing nodes, a probe filter, and a coherent slave. The coherent slave includes an early probe cache to cache recent lookups to the probe filter. The early probe cache includes entries for regions of memory, wherein a region includes a plurality of cache lines. The coherent slave performs parallel lookups to the probe filter and the early probe cache responsive to receiving a memory request. An early probe is sent to a first processing node responsive to determining that a lookup to the early probe cache hits on a first entry identifying the first processing node as an owner of a first region targeted by the memory request and responsive to determining that a confidence indicator of the first entry is greater than a threshold.

A cache coherency protection system provides for data redundancy by sharing a cache coherence memory pool for protection purposes. The system works consistently across all communication protocols, yields improved data availability with potentially less memory waster and makes data availability faster in node/director failure scenarios. According to various embodiments, the cache coherency protection system may include a writer/requester director that receives a write request from host, a protection target director that is a partner of the writer/request director and a directory.

A processing system includes a first set of one or more processing units including a first processing unit, a second set of one or more processing units including a second processing unit, and a memory having an address space shared by the first and second sets. The processing system further includes a distributed coherence directory subsystem having a first coherence directory to support a first subset of one or more address regions of the address space and a second coherence directory to support a second subset of one or more address regions of the address space. In some implementations, the first coherence directory is implemented in the system so as to have a lower access latency for the first set, whereas the second coherence directory is implemented in the system so as to have a lower access latency for the second set.

A method begins with a processing module of a dispersed storage network (DSN) receiving a first data object for storage in the DSN from a requesting entity based on an identifier associated with the first data object. The method continues with the processing module storing the first data object in the DSN, facilitating storage of the first data object in a cache memory using an address-based map and determining whether to transfer one or more data objects of a plurality of data objects from the cache memory. Based on a determination to transfer one or more data objects, the method continues by identifying a data object and another processing module to receive the data object, initiating a capacity query for the other processing module. The method continues with the processing module facilitating transfer of the second data object to the other processing module, receiving a transfer confirmation message; and facilitating updating the address-based map.

Data units are stored in private caches in nodes of a multiprocessor system, each node containing at feast one processor (CPU), at least one cache private to the node and at least one cache location buffer {CLB} private to the node. In each CLB location information values are stored, each location information value indicating a location associated with a respective data unit, wherein each location information value stored in a given CLB indicates the location to be either a location within the private cache disposed in the same node as the given CLB, to be a location in one of the other nodes, or to be a location in a main memory. Coherence of values of the data units is maintained using a cache coherence protocol The location information values stored in the CLBs are updated by the cache coherence protocol in accordance with movements of their respective data units.

A method and apparatus are provided for automatic routing of messages in a data processing system. An incoming message at an input/output (I/O) interface of the data processing system includes a message identifier and payload data. Match information, including an indicator or whether the message identifier of the incoming message matches an identifier of a request in a receive queue (RQ), is used to determine a destination for the incoming message. The incoming message is forwarded to the determined destination. Information, such as payload size and RQ position, may be used to determine allocation of the payload within a cache or cache hierarchy.