Datenverbindungsverfahren und Vorrichtung für Multiprozessor-Computersysteme mit gemeinsamem Speicher

摘要

In a shared memory multiprocessing computer system 20, multiple processors 22 - 24 can cache copies of a shared data block in their local cache memories 44 - 46 and independently modify their cached copies. The cached copies are later merged in a global memory 32, 33 with the shared data block. With each cached copy, a bitmask (56, 88, 220) (Figs. 2, 3, 5) consisting of a plurality of flags (60 - 64, 90 - 92, 240 - 244) associated with elements (70 - 74, 80 - 82, 230 - 234) of the cached copy also is stored in the local memory. A local memory controller 40 - 42 tracks which elements of the cached copies are modified by setting the bitmask flags associated with such elements. When merging, only modified elements of the cached copies are stored in the originating data block as indicated by the bitmask flags. The elements may be words, bytes or bits. Data reduction operations may be performed on data in the global memory. <IMAGE>