Data processing system, cache, and method of cache management including an O state for memory-consistent cache lines
US6397303B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1999 |
| Grant date | May 28, 2002 |
| Priority date | — |
| Expiry date | Jun 24, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0811
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multiprocessor data processing system includes an interconnect, a plurality of processing units coupled to the interconnect, and at least one system memory and a plurality of caches coupled to the plurality of processing units. A cache suitable for use in such a data processing system includes data storage containing multiple granules of data and a number of state fields associated with the granules of data. Each state field has a plurality of possible states including an O state indicating that an associated granule is consistent with corresponding data in the memory and has unknown coherency with respect to peer caches in the data processing system. Thus, a cache is permitted to store memory-consistent, but possibly non-coherent data in order to offer processing units in the data processing system lower latency to an image of system memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.