Memory controller that dynamically predicts page misses

摘要

A memory controller dynamically predicts whether a next memory cycle which is not yet available will result in a page miss or page hit condition. RAS lines are selectively precharged if the next memory cycle is predicted to be a page miss. The memory controller keeps track of various combinations of types of cycles when a type of memory cycle is followed by a type of non-memory pending cycle. For each such combination, the memory controller determines the percentage of combinations which result in a page hit on the next memory cycle. Using this history, the memory controller selectively precharges the RAS lines when a certain combination of types of cycles indicates a percentage of hits is below a predicted threshold. If a number of page hits exceeds the predicted threshold, precharging is not performed.