The present application is directed to a control circuit that provides a directory configured to maintain a plurality of entries, wherein each entry can indicate sharing of resources, such as cache lines, by a plurality of agents/hosts. Control circuit of the present invention can further provide consolidation of one or more entries having a first format to a single entry having a second format when resources corresponding to the one or more entries are shared by the agents. First format can include an address and a pointer representing one of the agents, and the second format can include a sharing vector indicative of more than one of the agents. In another aspect, the second format can utilize, incorporate, and/or represent multiple entries that may be indicative of one or more resources based on a position in the directory.

Synchronization events associated with cache coherence are monitored without using invalidations. A callback-read is issued to a memory address associated with the synchronization event, which callback-read either reads the last value written in the memory address or blocks until a next write takes place in the memory address and reads a newly written value.

Data units are stored in private caches in nodes of a multiprocessor system, each node containing at least one processor (CPU), at least one cache private to the node and at least one cache locations 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 for controlling access of a cache includes at least following steps: receiving a memory address; utilizing a hashing address logic to perform a programmable hash function upon at least a portion of the memory address to generate a hashing address; and determining an index of the cache based at least partly on the hashing address.

A method of controlling a cache is disclosed. The method comprises receiving a request to allocate a portion of memory to store data. The method also comprises directly mapping a portion of memory to an assigned contiguous portion of the cache memory when the request to allocate a portion of memory to store the data includes a cache residency request that the data continuously resides in cache memory. The method also comprises mapping the portion of memory to the cache memory using associative mapping when the request to allocate a portion of memory to store the data does not include a cache residency request that data continuously resides in the cache memory.

A caching system including a first sub-cache and a second sub-cache in parallel with the first sub-cache, wherein the second sub-cache includes a set of cache lines, line type bits configured to store an indication that a corresponding cache line of the set of cache lines is configured to store write-miss data, and an eviction controller configured to flush stored write-miss data based on the line type bits.

To reduce latency and bandwidth consumption in systems, systems and methods are provided for grouping multiple cache line request messages in a related and speculative manner. That is, multiple cache lines are likely to have the same state and ownership characteristics, and therefore, requests for multiple cache lines can be grouped. Information received in response can be directed to the requesting processor socket, and those speculatively received (not actually requested, but likely to be requested) can be maintained in queue or other memory until a request is received for that information, or until discarded to free up tracking space for new requests.

In an example, there is disclosed a host-fabric interface (HFI), including: an interconnect interface to communicatively couple the HFI to an interconnect; a network interface to communicatively couple the HFI to a network; network interface logic to provide communication between the interconnect and the network; a coprocessor configured to provide an offloaded function for the network; a memory; and a caching agent configured to: designate a region of the memory as a shared memory between the HFI and a core communicatively coupled to the HFI via the interconnect; receive a memory operation directed to the shared memory; and issue a memory instruction to the memory according to the memory operation.

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 programmable switch includes a plurality of ports for communication with devices on a network. Circuitry of the programmable switch is configured to receive a cache line request from a client on the network to obtain a cache line for performing an operation by the client. A port is identified for communicating with a memory device storing the cache line. The memory device is one of a plurality of memory devices used for a distributed cache. The circuitry is further configured to update a cache directory for the distributed cache based on the cache line request, and send the cache line request to the memory device using the identified port. In one aspect, it is determined whether the cache line request is for modifying the cache line.