Caching mechanism for remote read-only data in a cache coherent non-uniform memory access (CCNUMA) architecture
US6766360B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 2000 |
| Grant date | Jul 20, 2004 |
| Priority date | — |
| Expiry date | Jun 13, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/2542
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer network system for manipulating requests for shared data includes a plurality of groups and each group has a plurality of nodes and each node has a plurality of processors. The system further comprises a request outstanding buffer (ROB) for recording data requests, a remote access cache (RAC) for caching the results of prior memory requests which are remote to a requesting node, and a directory for recording a global state of a cache line in the system. The RAC supports only two states, Shared and Invalid, and caches only clean remote data. If the directory state is Modified/Exclusive, the line is indicated to not be in the RAC. The behavior of the RAC is described for two important cases: initial RAC does not have the line caches and initial RAC has the line cached. The requested data is supplied to the requesting node from the RAC when the RAC's line is cached and when the RAC's line is not cached, the requested data is supplied from the remote home node and the requested data is installed in the RAC. In the case when the data is not present in the RAC, the request to the remote home node is overlapped with the RAC access to minimize remote memory access latency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.