Method for operating a multiprocessor system for therein establishing a global binary assertion and a multiprocessor apparatus comprising synchronization means for such establishing, in particular for effecting a garbage collection operation
US4961137A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1987 |
| Grant date | Oct 2, 1990 |
| Priority date | — |
| Expiry date | Apr 17, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99957
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus is described for establishing a global binary assertion in a multiprocessor environment. The local objects have a three-value status variable: -active, disquiet-, -passive, quiet-, and -passive, disquiet- being the three values. First all local objects are made active. During execution, locally the assertion may hold, and thereupon a transition from active to -passive, quiet- is signalled to a global synchronizer process. Thereafter, cross-requests from a non-local object may reactivate a quiet object to the state -passive, disquiet-. The synchronizer process counts the transitions from active to -passive, quiet- and thus can detect when all objects are quiet. The local operations may represent a garbage collection system, wherein originally root items are colored grey and all other items white. In a marking phase, all grey items are successively accessed. After verifying any other item referred to by such grey item, and if white, discoloring it to grey, the original item is discolored to black. If locally no grey items are left, the local collector process goes to the state -passive, quiet-. Cross-processor references may awake it to either verifying a local…
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