Abstract: A data processing system utilizing a descriptor ring to facilitate communication between one or more general purpose processors and one or more devices employs a system memory management unit for managing access by the devices to a main memory. The system memory management unit uses address translation data for translating memory addresses generated by the devices into addresses supplied to the main memory. Prefetching circuitry within the system memory management unit serves to detect pointers read from the descriptor ring and to prefetch address translation data into the translation lookaside buffer of the system memory management unit.

Abstract: An apparatus for processing data 2 includes a memory 4 having a plurality of memory regions 28 to 38. A mapping controller 56 applies a variable mapping to map memory addresses of access requests to different regions within the memory 4. The mapping controller varies the mapping applied in dependence upon both one or more memory behavioral parameters indicative of behavioral characteristics of the different regions and one or more access behavioral parameters indicative of behavioral characteristics of an access request to be mapped. The memory behavioral parameters may include the temperature of the regions and/or the refresh period of the regions. The access behavior able parameters may include the quality of service level, the access frequency, the access volume and/or the identity of the source of the access request.

Abstract: An apparatus for processing data 2 includes a memory 4 having a plurality of memory regions 28 to 38. A mapping controller 56 applies a variable mapping to map memory addresses of access requests to different regions within the memory 4. The mapping controller varies the mapping applied in dependence upon both one or more memory behavioral parameters indicative of behavioral characteristics of the different regions and one or more access behavioral parameters indicative of behavioral characteristics of an access request to be mapped. The memory behavioral parameters may include the temperature of the regions and/or the refresh period of the regions. The access behavior able parameters may include the quality of service level, the access frequency, the access volume and/or the identity of the source of the access request.