Directory-based data transfer protocol for multiprocessor system
US7404045B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 2005 |
| Grant date | Jul 22, 2008 |
| Priority date | — |
| Expiry date | Aug 19, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0817
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A system for maintaining data coherency in a multiprocessor system includes a first processor having a cache and a directory, a second processor having a directory, and at least one additional processor having a directory and separate from the first and second processors. The first processor is configured to determine if a data line is not found in the cache of the first processor and forward a request for the data line to the second processor. The second processor is configured to forward the data line from the second processor to the first processor, update the directory of the second processor to reflect the data line being forwarded to the first processor, and forward a directory update message to the at least one additional processor to reflect the data line being forwarded to the first processor. An entry in the directories includes a memory address, a most recent data holder, and a line state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.