Method and apparatus to prefetch sequential pages in a multi-stream environment

Abstract

The present invention is system and method for determining information that is to be prefetched in a multi-stream environment which can detect sequential streams from among the aggregate reference stream and yet requires relatively little memory to operate, which is uniquely adapted for use in a multi-stream environment, in which multiple data accessing streams are performing sequential accesses to information independently of each other. A reference address referencing stored information is received. A matching run is found. A count corresponding to the run is updated. If the count exceeds a predetermined threshold, an amount of information to prefetch is determined. If a predetermined fraction of the determined amount of information to prefetch must still be retrieved, the determined amount of information is retrieved. A matching run may be found by searching a stack comprising a plurality of entries to find an entry corresponding to the reference address. Each of the plurality of entries may be associated with a maximum accessed address, a forward range, and a backward range, and the searching step may comprise searching the plurality of stack entries in one direction starting at an end of the stack and determining whether the reference address is between (maximum accessed address−backward range) and (maximum accessed address+forward range) for each stack entry until a matching stack entry is found.