Snoop Control Unit (SCU)

https://en.wikipedia.org/wiki/Bus_snooping

Saw this term on a random thread at NVIDIA.

A coherency controller (snooper) in a cache (a snoopy cache) monitors or snoops the bus transactions, and its goal is to maintain a Cache Coherency in distributed shared memory systems.

Bus Snooping

Bus snooping is a technique used in multiprocessor systems to keep the caches consistent. When a processor writes data to a memory location, the snooping mechanism checks if that location is also stored in other processor caches. If so, it updates or invalidates the corresponding entries to maintain coherence.