Multi-threaded read ahead prediction by pattern recognition
US6070230A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1997 |
| Grant date | May 30, 2000 |
| Priority date | — |
| Expiry date | Dec 29, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/6026
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The inventive prediction mechanism constructs a time ordered state space of the file accesses, and then searches the state space looking for file accesses that form either sequential or stride patterns. A cache is maintained to store information about existing patterns. The mechanism will review the cache to determine if a new access request is a continuation of an existing pattern before searching the entire state space for a new pattern. If the request is either a continuation of an existing pattern or forms a new pattern, then a read ahead is issued for the next block in the pattern. The cache and the state space are updated as each request arrives. The mechanism uses a trigger array to prevent the re-issuing of predictions. The mechanism also has a strength feature which is an indication how many times the pattern has been continued, and can be used by the operating system in deciding how many read aheads should be issued.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.