CPUtoCPU

CPUtoCPU is a term used to describe direct communication channels and protocols that enable two or more central processing units (CPUs) to exchange data, coordinate execution, and maintain cache coherence without relying solely on standard memory buses. It encompasses hardware interconnects, protocol stacks, and software interfaces that support low-latency messaging and synchronized operation in multi-processor systems.

In practice, CPUtoCPU implementations use high-speed interconnects—such as point-to-point links or scalable networks—to carry data payloads, control messages, and synchronization signals between CPUs. A typical CPUtoCPU stack includes addressing, flow control, error detection, and, where appropriate, cache-coherence messaging to keep private caches consistent across processors.

Architecturally, CPUtoCPU can be realized in various topologies, including direct dual-socket links or scalable fabrics that connect many CPUs. Efficient implementations provide low latency, high bandwidth, and predictable timing, while managing contention and memory coherence in a way that complements existing memory hierarchies and interconnects. Software support ranges from operating systems and schedulers that pin tasks to CPU domains to libraries and runtimes that expose explicit messaging or shared-memory semantics to applications.

Performance characteristics depend on interconnect design, protocol overhead, and the degree of coherence required. Benefits include reduced latency for tightly coupled parallel workloads and improved scalability in symmetric multiprocessing environments; drawbacks can include complexity, cost, and potential interference with memory traffic.

Common use cases include high-performance computing, real-time control systems, and virtualized environments that demand rapid CPU coordination. See also interconnect fabrics, cache coherence, NUMA, and symmetric multiprocessing.