公开(公告)号：DE3775332D1

公开(公告)日：1992-01-30

申请号：DE3775332

申请日：1987-08-18

Applicant: IBM

Inventor： HENNESSY JAMES PATRICK ,  OSISEK DAMIAN LEO ,  SEIGH II

IPC: G06F9/46 ,  G06F9/52

Abstract: In a multi-processing computer system, serialising references to shared data objects, such as pages, tables, and the like, that permits the system processors to reference objects on a shared access basis without obtaining a shared lock. A point of execution of the control program is monitored that is common to all processors in the system, which occurs regularly in the processors' execution and across which no references to any data object can be maintained by any process, except references using locks. A system reference point is established, which occurs after each process in the system has passed the monitored point of execution at least once since the last such system reference point. Operations requiring exclusive access, such as modification or destruction of the data object, are performed by, first, obtaining a conventional exclusive lock, then preventing any subsequent references to the data object, waiting until two of the system reference points have occurred, and, finally, performing the operation. Significant reductions in overhead can be achieved thereby.