Method and apparatus for a coherence transformer with limited memory for connecting computer system coherence domains
US5829034A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 1, 1996 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Jul 1, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/622
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A coherence transformer for allowing a computer node and one or more external devices to share memory blocks having local physical addresses at a memory module of the computer node. The coherence transformer includes logic for ascertaining whether a memory access request from the external device for a memory block should be responded to using a snoop-only approach or an Mtag-only approach. The snoop-only approach requires a tag in a snoop tag array of the coherence transformer be available to track the memory block for an entire duration that the memory block is cached by the external device. The Mtag-only approach only temporarily stores the memory block until a global state associated with the memory block can be written back into the memory module of the computer node. The snoop tag array allows the coherence transformer to snoop the bus of the computer node to intervene and respond to memory access requests pertaining to a memory block externally cached and tracked by the snoop tag array.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.