System and method for handling direct memory accesses
US7620779B1 · kind B1 · utility
Inventors
Key dates
| Filing date | May 22, 2006 |
| Grant date | Nov 17, 2009 |
| Priority date | — |
| Expiry date | Dec 20, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0831
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and systems for efficiently processing direct memory access requests coherently. An external agent requests data from the memory system of a computer system at a target address. A snoop cache determines if the target address is within an address range known to be safe for external access. If the snoop cache determines that the target address is safe, it signals the external agent to proceed with the direct memory access. If the snoop cache does not determine if the target address is safe, then the snoop cache forwards the request on to the processor. After the processor resolves any coherency problems between itself and the memory system, the processor signals the external agent to proceed with the direct memory access. The snoop cache can determine safe address ranges from such processor activity. The snoop cache invalidates its safe address ranges by observing traffic between the processor and the memory system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.