Memory hub and access method having internal prefetch buffers
First Claim
1. A memory module, comprising:
- a plurality of memory devices; and
a memory hub, comprising;
a link interface receiving memory requests for access to memory cells in at least one of the memory devices;
a memory device interface coupled to the memory devices, the memory device interface being operable to couple memory requests to the memory devices for access to memory cells in at least one of the memory devices and to receive read data responsive to at least some of the memory requests;
a history logic unit coupled to the link interface to receive memory requests from the link interface, the history logic being operable to predict addresses that are likely to be accessed in the memory devices based on the memory requests, the history logic unit generating prefetching suggestions indicative of the predicted addresses;
a memory sequencer coupled to the link interface, the memory device interface and the history logic unit, the memory sequencer being operable to couple memory requests to the memory device interface responsive to memory requests received from the link interface, the memory sequencer further being operable to generate and couple prefetching requests to the memory device interface responsive to prefetching suggestions received from the history logic unit;
a prefetch buffer coupled to the memory device interface for receiving and storing read data from memory cells being accessed responsive to the prefetching requests; and
a data read control unit coupled to the memory device interface, the link interface and the prefetch buffer, the data read control circuit being operable to determine from a read memory request received from the link interface if the read data are stored in the prefetch buffer, the control unit further being responsive to the read memory request to couple the read data from the prefetch buffer if the read data are stored in the prefetch buffer and to couple the read data from the memory device interface if the read data are stored in the memory devices.
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Accused Products
Abstract
A memory module includes a memory hub coupled to several memory devices. The memory hub includes history logic that predicts on the basis of read memory requests which addresses in the memory devices from which date are likely to be subsequently read. The history logic applies prefetch suggestions corresponding to the predicted addresses to a memory sequencer, which uses the prefetch suggestions to generate prefetch requests that are coupled to the memory devices. Data read from the memory devices responsive to the prefetch suggestions are stored in a prefetch buffer. Tag logic stores prefetch addresses corresponding to addresses from which data have been prefetched. The tag logic compares the memory request addresses to the prefetch addresses to determine if the requested read data are stored in the prefetch buffer. If so, the requested data are read from the prefetch buffer. Otherwise, the requested data are read from the memory devices.
163 Citations
2 Claims
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1. A memory module, comprising:
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a plurality of memory devices; and
a memory hub, comprising;
a link interface receiving memory requests for access to memory cells in at least one of the memory devices;
a memory device interface coupled to the memory devices, the memory device interface being operable to couple memory requests to the memory devices for access to memory cells in at least one of the memory devices and to receive read data responsive to at least some of the memory requests;
a history logic unit coupled to the link interface to receive memory requests from the link interface, the history logic being operable to predict addresses that are likely to be accessed in the memory devices based on the memory requests, the history logic unit generating prefetching suggestions indicative of the predicted addresses;
a memory sequencer coupled to the link interface, the memory device interface and the history logic unit, the memory sequencer being operable to couple memory requests to the memory device interface responsive to memory requests received from the link interface, the memory sequencer further being operable to generate and couple prefetching requests to the memory device interface responsive to prefetching suggestions received from the history logic unit;
a prefetch buffer coupled to the memory device interface for receiving and storing read data from memory cells being accessed responsive to the prefetching requests; and
a data read control unit coupled to the memory device interface, the link interface and the prefetch buffer, the data read control circuit being operable to determine from a read memory request received from the link interface if the read data are stored in the prefetch buffer, the control unit further being responsive to the read memory request to couple the read data from the prefetch buffer if the read data are stored in the prefetch buffer and to couple the read data from the memory device interface if the read data are stored in the memory devices.
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2-53. -53. (canceled)
Specification