High performance symmetric multiprocessing systems via super-coherent data mechanisms
US6785774B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 2001 |
| Grant date | Aug 31, 2004 |
| Priority date | — |
| Expiry date | Oct 3, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0831
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multiprocessor data processing system comprising a plurality of processing units, a plurality of caches, that is each affiliated with one of the processing units, and processing logic that, responsive to a receipt of a first system bus response to a coherency operation, causes the requesting processor to execute operations utilizing super-coherent data. The data processing system further includes logic eventually returning to coherent operations with other processing units responsive to an occurrence of a pre-determined condition. The coherency protocol of the data processing system includes a first coherency state that indicates that modification of data within a shared cache line of a second cache of a second processor has been snooped on a system bus of the data processing system. When the cache line is in the first coherency state, subsequent requests for the cache line is issued as a Z1 read on a system bus and one of two responses are received. If the response to the Z1 read indicates that the first processor should utilize local data currently available within the cache line, the first coherency state is changed to a second coherency state that indicates to the first proce…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.