Shared memory multiprocessing system employing mixed broadcast snooping and directory based coherency protocols
US7032078B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 2002 |
| Grant date | Apr 18, 2006 |
| Priority date | — |
| Expiry date | May 13, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/0817
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multiprocessor computer system to selectively transmit address transactions using a broadcast mode or a point-to-point mode. Either a directory-based coherency protocol or a broadcast snooping coherency protocol is implemented to maintain coherency. A node is formed by a group of clients which share a common address and data network. The address network determines whether a transaction is conveyed in broadcast mode or point-to-point mode. The address network includes a table with entries which indicate transmission modes corresponding to different regions of the address space within the node. Upon receiving a coherence request transaction, the address network may access the table to determine the transmission mode which corresponds to the received transaction. Network congestion may be monitored and transmission modes adjusted accordingly. When network utilization is high, the number of transactions which are broadcast may be reduced. Alternatively, when network utilization is low, the number of broadcasts may be increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.