The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 1994
Filed:
Aug. 30, 1991
Mark L Palmer, Hollis, NH (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
Prefetches to a cache memory subsystem are made from predictions which are based on access patterns stored by context. An access pattern is generated from prior accesses of a data processing system processing in a like context. During a training sequence, an actual trace of memory accesses is processed to generate unit patterns which serve in making future predictions and to identify statistics such as pattern accuracy for each unit pattern. In a replacement list, prefetched objects are included at the head of the list. Within a prefetch, objects are listed by order of expected time of access, with alternatives at predicted times of access. When an object is used, it is moved to the head of the list and any prefetched alternatives to that object, indicated by like time marks, are moved to the tail of the list. Alternatives may be listed according to degree of match of a current access pattern and a stored access pattern and by prior accuracy of the unit pattern. A server includes a demand access queue which preempts fetches of objects identified by a prefetch queue.