A decentralized virtual memory scheme implemented on an emulated multiprocessor

A decentralized scheme for virtual memory management on MIMD (multiple-instruction-multiple-data) multiprocessors with shared memory has been developed. Control and data structures are kept local to the processing elements (PE), which reduces the global traffic and makes a high degree of parallelism possible. Each of the PEs in the target architecture consists of a processor and part of the shared memory and is connected to the others by a common bus. The traditional approach, based on replication or sharing of data structures is not suitable in this case when the number of PEs is of the magnitude of 100. This is due to the excessive global traffic caused by consistency or mutual exclusion protocols. A variant of the Dennings working set page replacement algorithm is used, in which each process owns a page list. Shared pages are not present in more than one list, and it is shown that this will not increase the page fault rate in most cases