发明名称 HYBRID CACHE CONTROL
摘要 In a cache storage system a sharing (SH) flag is provided with each line representation in the cache directory to uniquely indicate for each cache line whether it is to be handled as a store-in-cache (SIC) line when its SH flag is in non-sharing state, and as a store-through (ST) cache line when its SH flag is in sharing state. At any time the hybrid cache can have some lines operating as ST lines, and other lines as SIC lines. Such cache storage systems are used as private caches in a multiprocessor (MP) system. <??>A newly fetched line (resulting from a cache miss) has its SH flag set to non-sharing (SIC) state in its location determined by cache replacement selection circuits, unless the SH flag for the requested line is dynamically set to sharing (ST) state if a cross-interrogation (XI) hit in another cache is found by cross-interrogation (XI) controls, which interrogates all other cache directories in the MP for every store or fetch cache miss and for every store cache hit of a ST line (having SH=1). <??>A XI hit signals that a conflicting copy of the line has been found in another cache. In the conflicting cache line is changed from its corresponding main storage (MS) line, the cache line is castout to MS. The sharing (SH) flag for the conflicting line is set to sharing state for a fetch miss, but the conflicting line is invalidated for a store miss.
申请公布号 DE3278863(D1) 申请公布日期 1988.09.08
申请号 DE19823278863 申请日期 1982.11.16
申请人 INTERNATIONAL BUSINESS MACHINES CORPORATION 发明人 FLETCHER, ROBERT PERCY
分类号 G06F12/08;(IPC1-7):G06F12/08 主分类号 G06F12/08
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