| 摘要 |
Speculative pre-fetching and pre-flushing of additional cache lines minimize cache miss latency and coherency check latency of an out of order instruction execution processor. A pre-fetch/pre-flush slot (DPRESLOT) is provided in a memory queue (MQUEUE) of the out-of-order execution processor. The DPRESLOT monitors the transactions between a system interface, e.g., the system bus, and an address reorder buffer slot (ARBSLOT) and/or between the system interface and a cache coherency check slot (CCCSLOT). When a cache miss is detected, the DPRESLOT causes one or more cache lines in addition to the data line, which caused the current cache miss, to be pre-fetched from the memory hierarchy into the cache memory (DCACHE) in anticipation that the additional data would be required in the near future. When a cache write back is detected as a result of a cache coherency check, the DPRESLOT causes one or more cache lines, in addition to the data line currently being written back, to be pre-flushed out to the memory hierarchy from the respective cache memory (DCACHE) of the processor that owns the line, in anticipation that the additional data would be required by the requesting processor in the near future. A logic included in the DPRESLOT prevents a cache miss request for the additional data when another request has already been made for the data.
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