A method and memory controller for adaptive row management within a memory
subsystem provides metrics for evaluating row access behavior and
dynamically adjusting the row management policy of the memory subsystem
in conformity with measured metrics to reduce the average latency of the
memory subsystem. Counters provided within the memory controller track
the number of consecutive row accesses and optionally the number of total
accesses over a measurement interval. The number of counted consecutive
row accesses can be used to control the closing of rows for subsequent
accesses, reducing memory latency. The count may be validated using a
second counter or storage for improved accuracy and alternatively the row
close count may be set via program or logic control in conformity with a
count of consecutive row hits in ratio with a total access count. The
control of row closure may be performed by a mode selection between
always closing a row (non-page mode) or always holding a row open (page
mode) or by intelligently closing rows after a count interval (row hold
count) determined from the consecutive row access measurements. The logic
and counters may be incorporated within the memory controller or within
the memory devices and the controller/memory devices may provide I/O
ports or memory locations for reading the count values and/or setting a
row management mode or row hold count.