A distributed storage system comprises a first module and a second module. The first module processes read requests for an address range, to send to the second module. The first module receives an address associated with a read request for a data page stored on the second module. A method searches a table on the first module for a content-based signature of the data page based on the address and provides the data page from a first module read cache if the content-based signature is in the read cache, where content-based signatures in the table are associated with the address range.

The present invention relates to a method of transmitting a message comprising an integrity check and a header, between two processing units via a shared memory, comprising steps of: —generation (501), by a first processing unit, of a first pseudorandom binary string; —encryption (502) of the message to be transmitted by applying an involutive transformation dependent on the first pseudorandom binary string generated; —transmission and storage (503) of the encrypted message in the shared memory; —generation (504), by the second processing unit, of a second pseudorandom binary string; —decryption of the message stored by applying an involutive transformation dependent on the second pseudorandom binary string, and by decrypting the header (505) of said message, by verifying the decrypted header (505), and as a function of the result of the verification, by decrypting the complete message (506); —verification (507) of the integrity of the decrypted message on the basis of its integrity check.

A distributed metadata cache for a distributed object store includes a plurality of cache entries, an active-cache-entry set and an unreferenced-cache-entry set. Each cache entry includes information relating to whether at least one input/output (IO) thread is referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread. Each cache entry in the active-cache-entry set includes information that indicates that at least one IO thread is actively referencing the cache entry. Each cache entry in the unreferenced-cache-entry set is eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread.

Techniques are disclosed relating to controlling cache replacement. In some embodiments, search control circuitry is configured to perform multiple searches of a data structure (e.g., page table walks) where searches traverse multiple links between elements of the data structure. In some embodiments, a traversal cache caches traversal information that is usable by searches to skip one or more links traversed by one or more prior searches. In some embodiments, tracking control circuitry stores tracking information in a first entry, where the tracking information indicates a location in the traversal cache at which prior traversal information for a first search is stored. In some embodiments, replacement control circuitry selects, based on the tracking information in the first entry of the tracking control circuitry, an entry in the traversal cache for new traversal information generated by the first search (which may include selecting the first entry to override a default replacement policy).

Techniques are provided for maintaining and recomputing reference counts in a persistent memory file system of a node. Primary reference counts are maintained for pages within persistent memory of the node. In response to receiving a first operation to link a page into a persistent memory file system of the persistent memory, a primary reference count of the page is incremented before linking the page into the persistent memory file system. In response to receiving a second operation to unlink the page from the persistent memory file system, the page is unlinked from the persistent memory file system before the primary reference count is decremented. Upon the node recovering from a crash, the persistent memory file system is traversed in order to update shadow reference counts for the pages with correct reference count values, which are used to overwrite the primary reference counts with the correct reference count values.

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.

Systems and methods are disclosed including a first memory device, a second memory device coupled to the first memory device, where the second memory device has a lower access latency than the first memory device and acts as a cache for the first memory device. A processing device operatively coupled to the first and second memory devices can track access statistics of segments of data stored at the second memory device, the segments having a first granularity, and determine to update, based on the access statistics, a segment of data stored at the second memory device from the first granularity to a second granularity. The processing device can further retrieve additional data associated with the segment of data from the first memory device and store the additional data at the second memory device to form a new segment having the second granularity.

A method for using a distributed memory device in a memory augmented neural network system includes receiving, by a controller, an input query to access data stored in the distributed memory device, the distributed memory device comprising a plurality of memory banks. The method further includes determining, by the controller, a memory bank selector that identifies a memory bank from the distributed memory device for memory access, wherein the memory bank selector is determined based on a type of workload associated with the input query. The method further includes computing, by the controller and by using content based access, a memory address in the identified memory bank. The method further includes generating, by the controller, an output in response to the input query by accessing the memory address.

A programmable switch includes ports, and circuitry to receive cache messages for a distributed cache from client devices. The cache messages are queued for sending to memory devices from the ports. Queue occupancy information is generated and sent to a controller that determines, based at least in part on the queue occupancy information, at least one of a cache message transmission rate for a client device, and one or more weights for the queues used by the programmable switch. In another aspect, the programmable switch extracts cache request information from a cache message. The cache request information indicates a cache usage and is sent to the controller, which determines, based at least in part on the extracted cache request information, at least one of a cache message transmission rate for a client device, and one or more weights for queues used in determining an order for sending cache messages.

A programmable switch includes at least one memory configured to store a cache directory for a distributed cache, and circuitry configured to receive a cache line request from a client device to obtain a cache line. The cache directory is updated based on the received cache line request, and the cache line request is sent to a memory device to obtain the requested cache line. An indication of the cache directory update is sent to a controller for the distributed cache to update a global cache directory. In one aspect, the controller sends at least one additional indication of the update to at least one other programmable switch to update at least one backup cache directory stored at the at least one other programmable switch.