An apparatus and method is provided, the apparatus comprising a processor pipeline to execute instructions, a cache structure to store information for reference by the processor pipeline when executing said instructions; and prefetch circuitry to issue prefetch requests to the cache structure to cause the cache structure to prefetch information into the cache structure in anticipation of a demand request for that information being issued to the cache structure by the processor pipeline. The processor pipeline is arranged to issue a trigger to the prefetch circuitry on detection of a given event that will result in a reduced level of demand requests being issued by the processor pipeline, and the prefetch circuitry is configured to control issuing of prefetch requests in dependence on reception of the trigger.

The invention discloses a data structure-aware prefetching method and device on a graphics processing unit. The method comprises the steps of acquiring information for a memory access request in which a monitoring processor checks a graph data structure and read data, using a data structure access mode defined by a breadth first search and graph data structure information to generate four corresponding vector prefetching requests and store into a prefetching request queue. The device comprises a data prefetching unit distributed into each processing unit, each data prefetching unit is respectively connected with an memory access monitor, a response FIFO and a primary cache of a load/store unit, and comprises an address space classifier, a runtime information table, prefetching request generation units and the prefetching request queue. According to the present invention, data required by graph traversal can be prefetched more accurately and efficiently using the breadth first search, thereby improving the performance of GPU to solve a graph computation problem.

Techniques are provided for adaptive look-ahead configuration for data prefetching. One method comprises, in response to a request for a data item in a storage system: obtaining a size of a look-ahead window for the request based on one of multiple available caching policies; and moving the requested data item and additional data items within the look-ahead window to the cache memory when the requested data item and/or the additional data items within the look-ahead window are not in the cache memory. The multiple available caching policies comprise a caching policy based on characteristics of an input/output workload of the storage system, or a portion thereof; and/or a caching policy based on an input/output workload of at least a portion of the storage system within a prior predefined time window. The look-ahead window size may be varied over time.

Disclosed is a computer-implemented method to increase the efficiency of a prefetch system. The method includes receiving a system call including an instruction address. The method includes determining a confidence score. The method further includes creating an entry, including the instruction address, an associated data address, and the confidence score. The method includes determining the instruction address is not present in a history table, where the history table includes a plurality of entries. The method further includes determining, in response to adding the first entry to the history table, a second entry is evicted from the history table. The method includes entering the second entry into a filter table in response to determining the second confidence score is a moderate confidence score, where the moderate confidence score is any confidence score that is greater than a predefined low threshold and less than a predefined high threshold.

The present invention discloses a method and a system for managing cache memory. The system comprising a processor is configured to receive datasets from one or more applications, segregate the received datasets into one or more data blocks, identify a checkpoint from previously created checkpoints stored in a virtual cache corresponding to the one or more data blocks, wherein the checkpoints are previously created based on frequency of repetition of each of the one or more data blocks and association between the each of the one or more data blocks, recall a sequence of previously stored data blocks from main memory based on the identified checkpoint, and send the sequence of previously stored data blocks to the one or more applications for execution, thereby managing cache memory.

The invention discloses a prefetch-adaptive intelligent cache replacement policy for high performance, in the presence of hardware prefetching, a prefetch request and a demand request are distinguished, a prefetch predictor based on an ISVM (Integer Support Vector Machine) is used for carrying out re-reference interval prediction on a cache line of prefetching access loading, and a demand predictor based on an ISVM is utilized to carry out re-reference interval prediction on a cache line of demand access loading. A PC of a current access load instruction and PCs of past load instructions in an access historical record are input, different ISVM predictors are designed for prefetch and demand requests, reuse prediction is performed on a loaded cache line by taking a request type as granularity, the accuracy of cache line reuse prediction in the presence of prefetching is improved, and performance benefits from hardware prefetching and cache replacement is better fused.

Virtual storage arrays consolidate branch data storage at data centers connected via wide area networks. Virtual storage arrays appear to storage clients as local data storage; however, virtual storage arrays actually store data at the data center. The virtual storage arrays overcomes bandwidth and latency limitations of the wide area network by predicting and prefetching storage blocks, which are then cached at the branch location. Virtual storage arrays leverage an understanding of the semantics and structure of high-level data structures associated with storage blocks to predict which storage blocks are likely to be requested by a storage client in the near future. Virtual storage arrays determine the association between requested storage blocks and corresponding high-level data structure entities to predict additional high-level data structure entities that are likely to be accessed. From this, the virtual storage array identifies the additional storage blocks for prefetching.

A method for transferring data may include writing, from a producing device, data to a storage device through an interconnect, determining a consumer device for the data, prefetching the data from the storage device, and transferring, based on the determining, the data to the consumer device through the interconnect. The method may further comprise receiving, at a prefetcher for the storage device, an indication of a relationship between the producing device and the consumer device, and determining the consumer device based on the indication. The method may further comprise placing the data in a stream at the storage device based on the relationship between the producing device and the consumer device. The indication may be provided by an application associated with the consumer device. Receiving the indication may include receiving the indication through a coherent memory protocol for the interconnect.

An electronic device includes a cache, a processing cluster having one or more processors, and prefetch throttling circuitry that determines a congestion level of the processing cluster based on an extent to which the data retrieval requests sent from the processors to the cache are not satisfied by the cache. Congestion criteria require that the congestion level of the cluster is above a cluster congestion threshold. In accordance with a determination that the congestion level of the cluster satisfies the congestion criteria, the prefetch throttling circuit causes one of the processors to limit prefetch requests to the cache to prefetch requests of at least a threshold quality. In accordance with a determination that the congestion level of the cluster does not satisfy the congestion criteria, the prefetch throttling circuit forgoes causing the processors to limit prefetch requests to the cache to prefetch requests of at least the threshold quality.

Memory pages of a local application program are prefetched from a memory of a remote host. A method of prefetching the memory pages from the remote memory includes detecting that a cache-line access made by a processor executing the local application program is an access to a cache line containing page table data of the local application program, identifying data pages that are referenced by the page table data, and fetching the identified data pages from the remote memory and storing the fetched data pages in a local memory.