Precise synchronization mechanism for SMP system buses using tagged snoop operations to avoid retries
US6029204A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Mar 13, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F9/52
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method of synchronizing an initiating processing unit in a multi-processor computer system with other processing units in the system, by assigning a unique tag for each processing unit, and issuing synchronization messages which include the unique tag of an initiating processing unit. The processing units each have a snoop queue for receiving snoop operations and corresponding tags associated with instructions issued by an initiating processing unit, and the processors examine their respective snoop queues to determine whether any snoop operation in those queues has a tag which is the unique tag of the initiating processing unit. A retry message is sent to the initiating processing unit from any of the other processing units which determine that a snoop operation in a snoop queue has a tag which is the unique tag of the initiating processing unit. In response to the retry message, the initiating processing unit re-issues the synchronization message, and the other processors re-examine their respective snoop queues, in response to the re-issuing of the synchronization message, to determine whether any snoop operation in those queues still has a tag which is the unique tag of the i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.