50results about How to "Lower memory access latency" patented technology

A data processing system includes one or more processing cores, a system memory having multiple rows of data storage, and a memory controller that controls access to the system memory and performs supplier-based memory speculation. The memory controller includes a memory speculation table that stores historical information regarding prior memory accesses. In response to a memory access request, the memory controller directs an access to a selected row in the system memory to service the memory access request. The memory controller speculatively directs that the selected row will continue to be energized following the access based upon the historical information in the memory speculation table, so that access latency of an immediately subsequent memory access is reduced.

A control system for memory access includes a system memory access command buffer, a memory access command parallel processor, a DRAM command controller and a read data buffer. The system memory access command buffer stores plural system memory access commands. The memory access command parallel processor is connected to the system memory access command buffer for fetching and decoding the system memory access commands to plural DRAM access commands, storing the DRAM access commands in DRAM bank command FIFOs, and performing priority setting according to a DRAM bank priority table. The DRAM command controller is connected to the memory access command parallel processor and a DRAM for receiving the DRAM access commands, and sending control commands to the DRAM. The read data buffer is connected to the DRAM command controller and the system bus for storing the read data and rearranging a sequence of the read data.

A data processing system includes a system memory, one or more processing cores, and a memory controller that controls access to a system memory. The memory controller includes a memory speculation mechanism that stores historical information regarding prior memory accesses. In response to a memory access request, the memory controller speculatively initiates access to the system memory based upon the historical information in the memory speculation mechanism in advance of receipt of a coherency message indicating that the memory access request is to be serviced by reference to the system memory.

The application describes a data processor operable to process data, and comprising: a cache in which a storage location of a data item within said cache is identified by an address, said cache comprising a plurality of storage locations and said data processor comprising a cache directory operable to store a physical address indicator for each storage location comprising stored data; a hash value generator operable to generate a generated hash value from at least some of said bits of said address said generated hash value having fewer bits than said address; a buffer operable to store a plurality of hash values relating to said plurality of storage locations within said cache; wherein in response to a request to access said data item said data processor is operable to compare said generated hash value with at least some of said plurality of hash values stored within said buffer and in response to a match to indicate a indicated storage location of said data item; and said data processor is operable to access one of said physical address indicators stored within said cache directory corresponding to said indicated storage location and in response to said accessed physical address indicator not indicating said address said data processor is operable to invalidate said indicated storage location within said cache.

A system and method for increasing the throughput of a processor during cache misses. During the retrieval of the cache miss data, subsequent memory requests are generated and allowed to proceed to the cache. The data for the subsequent cache hits are stored in a bypass retry device. Also, the cache miss address and memory line data may be stored by the device when they are retrieved and they may be sent them to the cache for a cache line replacement. The bypass retry device determines the priority of sending data to the processor. The priority allows the data for memory requests to be provided to the processor in the same order as they were generated from the processor without delaying subsequent memory requests after a cache miss.

A multiprocessor system includes a plurality of data processing nodes. Each node has a processor coupled to a system memory, a cache memory, and a cache directory. The cache directory contains cache coherency information for a predetermined range of system memory addresses. An interconnection enables the nodes to exchange messages. A node initiating a function shipping request identifies an intermediate destination directory based on a list of the function's operands and sends a message indicating the function and its corresponding operands to the identified destination directory. The destination cache directory determines a target node based, at least in part, on its cache coherency status information to reduce memory access latency by selecting a target node where all or some of the operands are valid in the local cache memory. The destination directory then ships the function to the target node over the interconnection.

Logic such as a memory controller writes primary data from an incoming write request as well as corresponding replicated primary data (which is a copy of the primary data) to one or more different memory banks of random access memory in response to determining a memory access contention condition for the address (including a range of addresses) corresponding to the incoming write request. When the memory bank containing the primary data is busy servicing a write request, such as to another row of memory in the bank, a read request for the primary data is serviced by reading the replicated primary data from the different memory bank of the random access memory to service the incoming read request.