Method of varying the amount of data prefetched to a cache memory in dependence on the history of data requests
US5146578A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 12, 1991 |
| Grant date | Sep 8, 1992 |
| Priority date | — |
| Expiry date | Apr 12, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/6026
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of dynamically prefetching data for a cache memory is controlled by the past history of data requests. If the previous fetch and current fetch request are not sequential, no data is prefetched. If the previous fetch and current fetch request are sequential and less than all of the current fetch request is already in the cache, two blocks of data sequentially beyond the current fetch request are prefetched. If the previous two blocks fetched and current fetch request are sequential and less than all of the current fetch request is already in the cache, four blocks of data sequentially beyond the current fetch request are prefetched. If the previous three blocks fetched and the current fetch request are sequential and less than all of the current fetch request is already in the cache, eight blocks of data sequentially beyond the current fetch request are preferred. The prefetch algorithm is limited at eight blocks. Each additional sequential request less than all of which is already in the cache will cause eight blocks to be prefetched.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.