A single cached copy data coherence scheme for multiprocessor systems

Abstract

We present and evaluate a snoopy cache memory protocol, the Single Cache Copy Data Coherence (SCCDC), for multiprocessors that allows only a single cache to hold a given share-d data at any time. The simulations presented here indicate that despite its simplicity, the scheme has the potential for good performance comparable with more complex snoopy cache schemes. We have also shown in related work [8] that the existence of only a single copy of data in cache allows efficient access control to shared data by minimizing the overh-ead caused by critical sections. Thus, with low implementation cost, and the efficient support for important operating system functions, the SCCDC scheme appears attractive for multi-user, multi-thread environments where the actual shared rate is modest, and mostly caused by synchronization mechanisms.