Hashing Strategies for Simulating Shared Memory on Distributed Memory Machines

We survey shared memory simulations on distributed memory machines (DMMs), that use universal hashing to distribute the shared memory cells over the memory modules of the DMM. We measure their quality in terms of delay, time-processor eeciency, memory contention (how many requests have to be satissed by one memory module per simulated step) and simplicity. Further we take into consideration diierent access connict rules to the modules of the DMM, in particular the c-Collision rule motivated by the idea of communicating between processors and modules using an optical crossbar. It turns out that simulations with very small delay require more than one hash function. Further, simple simulations on DMMs with the c-Collision rule are only known if more than one hash function is allowed.