Trace-Driven Simulation Of Data-Alignment And Other Factors Affecting Update And Invalidate Based Coherent Memory

The exploitation of locality of reference in shared memory multiprocessors is one of the most important problems in parallel processing today. Locality can be managed in several levels: hardware, operating system, runtime environment of the compiler, user level. In this paper we investigate the problem of exploiting locality at the operating system level and its interactions with the compiler and the architecture. Our main conclusion, based on trace-driven simulations of real applications, is that exploitation of locality is effective only if all three levels cooperate. The compiler should do sophisticated data alignment, the operating system should perform on-line caching and page replication, while the architecture should provide simple but effective hardware mechanisms that assist the operating system in avoiding unnecessary movement of data. Institute of Computer Science, F.O.R.T.H. E-mail fmarkatos,chronakig@csi.forth.gr or fmarkatos,chronakig@ariadne.bitnet 1 Introduction Th..