Coherence Circuitry for Memory Domain Access

The patent implements a feedback mechanism where the coherence circuitry monitors cache write operations and generates appropriate memory maintenance commands (such as invalidate or update commands) to keep main memory and other caches synchronized. This feedback loop ensures that when data is written to cache, the coherence system detects this change and propagates the update or invalidation information to other caches and main memory, thus maintaining data coherency while allowing fast writeback cache operations.

The patent introduces coherence circuitry as an intermediary component between the cache system and main memory. This intermediary monitors cache operations, translates cache writes into appropriate memory maintenance commands, and coordinates updates across multiple caches and main memory. The intermediary handles the complexity of coherency management separately, allowing the cache to operate at high speed while the intermediary ensures data consistency across the system.

The patent segments the coherency management function into a dedicated coherence circuitry component separate from the processors and caches. Each processor and cache can operate independently in parallel, while the coherence circuitry is divided into multiple coherence domains that can handle coherency requests from different processors simultaneously. This segmentation allows parallel processing to proceed without bottlenecking on coherency management, as the coherence system is also parallelized and distributed.

The coherence circuitry acts as an intermediary that mediates between multiple processors and caches, handling coherency protocols without requiring the processors themselves to manage coherency complexity. The intermediary translates processor memory requests into cache-coherent operations, managing the complex state transitions and protocol handshaking required for multi-processor coherency while keeping the processor logic simple and focused on computation.