Cache coherence protocol for a multiple bus multiprocessor system

摘要

A computer system maintains a list of tags (called a Global Ownership Tag List (GOTL)) for all the cache lines in the system that are owned by a cache. The GOTL is used for cache coherence. There may be one central GOTL. Alternatively, the GOTL may be distributed, so that every device that can request a copy of memory data maintains a local copy of the GOTL. The GOTL can be limited to a relatively small size. For a limited size list, a tag may need to be evicted to make room for a new tag. A line associated with an evicted tag must be written back to memory.