Dynamic decentralized cache schemes for mimd parallel processors

This paper presents two cache schemes for a shared-memory shared bus multiprocessor. Both schemes feature decentralized consistency control and dynamic type classification of the datum cached (i.e. read-only, local, or shared). It is shown how to exploit these features to minimize the shared bus traffic. The broadcasting ability of the shared bus is used not only to signal an event but also to distribute data. In addition, by introducing a new synchronization construct, i.e. the Test-and-Test-and-Set instruction, many of the traditional. parallell processing “hot spots” or bottlenecks are eliminated. Sketches of formal correctness proofs for the proposed schemes are also presented. It appears that moderately large parallel processors can be designed by employing the principles presented in this paper.