Granularity of parallel memories

Abstract

Consider algorithms which are designed for shared memory models of parallel computation in which processors are allowed to have fairly unrestricted access patterns to the shared memory. General fast simulations of such algorithms by parallel machines in which the shared memory is organized in modules where only one cell of each module can be accessed at a time are proposed. The paper provides a comprehensive study of the problem. The solution involves three stages: (a) Before a simulation, distribute randomly the memory addresses among the memory modules. (b) Keep several copies of each address and assign memory requests of processors to the "right'; copies at any time. (c) Satisfy these assigned memory requests according to specifications of the parallel machine.