Method and apparatus for ensuring data consistency between an i/o channel and a processor
US6108721A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1998 |
| Grant date | Aug 22, 2000 |
| Priority date | — |
| Expiry date | Jun 29, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/28
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a method and apparatus that ensures data consistency between an I/O channel and a processor, system software issues an instruction which causes the issuance of a transaction when notification of a DMA completion is received. The transaction instructs the I/O channel to enforce coherency and then responds back only after coherency has been ensured. Specifically, a DMA.sub.-- SYNC transaction is broadcast to all I/O channels in the system. Responsive thereto, each I/O channel writes back to memory any modified lines in its cache that might contain DMA data for a DMA sequence that was reported by the system as completed. The I/O channels have a reporting means to indicate when this transaction is completed, so that the DMA.sub.-- SYNC transaction does not have to complete in pipeline order. Thus, the I/O channel can issue new transactions before responding to the DMA.sub.-- SYNC transaction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.