Cross-Interrogate Line Buffers
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
A major source of multiprocessor degradation is the cross-interrogation of one processor's cache by the other. The following reduces the penalty for a cross-interrogation. Analysis has shown that a technique based on the least recently used (LRU) status of cache lines subject to cross-interrogation identifies these lines as the subject of re-cross-interrogation by the original processor. The penalty experienced by a processor whose line is cross-interrogated can be reduced if the line can merely be invalidated and a current copy is provided by the proposed cross-interrogate (XI) line buffer. Fig. 1 shows a 2-way multiprocessor (MP) which maintains XI buffers for a subset of cache lines.