“SLIME” cache coherency system for agents with multi-layer caches
US6378048B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1998 |
| Grant date | Apr 23, 2002 |
| Priority date | — |
| Expiry date | Nov 12, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0811
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A cache coherency method, a data eviction method, and a multi-level cache system are disclosed. A copy of data may take one of five states including a shared state, a lazy state, an invalid state, a modified state, and an exclusive state. Based upon the names of these states, the disclosed methods and systems may be labeled “SLIME.” The method of cache coherency may include storing a copy of data in a cache and storing state information identifying the copy as being stored in one of the five above-mentioned states. In response to a snoop request related to the data, marking a status field indicative of the state of the data to represent that the data is shared without regard to the data's dirty status. The data eviction method includes storing data in a cache, storing a status field in association with the data, the status field having a first sub-field to indicate whether the data is dirty and a second sub-field to indicate whether the data is shared, when the data is to be evicted from the cache, testing the first sub-field field to determine whether the data is dirty and, if so, writing the data to another cache before evicting the data from the cache. The multi-laye…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.