Qualcomm Incorporated

Nikhil Narendradev Sharma

Thomas Philip Speier

Eric Francis Robinson

Garrett M Drapala

Joseph Gerald McDonald

Harold Wade Cain, Iii

Brian Stempel

David Scott Ray

Perry Willmann Remaklus, Jr

Niket Choudhary

An apparatus, method, and system for memory bandwidth aware data prefetching is presented. The method may comprise monitoring a number of request responses received in an interval at a current prefetch request generation rate, comparing the number of request responses received in the interval to at least a first threshold, and adjusting the current prefetch request generation rate to an updated prefetch request generation rate by selecting the updated prefetch request generation rate from a plurality of prefetch request generation rates, based on the comparison. The request responses may be NACK or RETRY responses. The method may further comprise either retaining a current prefetch request generation rate or selecting a maximum prefetch request generation rate as the updated prefetch request generation rate in response to an indication that prefetching is accurate.

Method, apparatus, and system for memory bandwidth aware data prefetching

Selective honoring of speculative memory-prefetch requests based on bandwidth constraint of a memory access path component(s) in a processor-based system. To reduce memory access latency, a CPU includes a request size in a memory read request of requested data to be read from memory and a request mode of the requested data as required or preferred. A memory access path component includes a memory read honor circuit configured to receive the memory read request and consult the request size and request mode of requested data in the memory read request. If the selective prefetch data honor circuit determines that bandwidth of the memory system is less than a defined bandwidth constraint threshold, then the memory read request is forwarded to be fulfilled, otherwise, the memory read request is downgraded to only include any requested required data.

Selectively honoring speculative memory prefetch requests based on bandwidth state of a memory access path component(s) in a processor-based system

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Nikhil Narendradev Sharma