Coherence control by data invalidation in selected processor caches without broadcasting to processor caches not having the data
US5265232A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1991 |
| Grant date | Nov 23, 1993 |
| Priority date | — |
| Expiry date | Apr 3, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0811
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A coherence directory and its methods of operation are disclosed for private processor caches in a multiple processor system to control data coherence in the system. It provides cross-invalidate (XI) controls for the assignment of exclusive and public ownership to data units in the processor caches, including required cross-invalidation of data units among the processor caches to obtain data coherence in the system in an efficient manner. The coherence directory can be used in a multiple processor system with or without any shared second level (L2) cache, shared or private. When a shared L2 cache is used to improve system access time, the coherence directory can also be used as the second level directory for the shared L2 cache and eliminate the need for any additional L2 directory(s).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.