> This has an advantage compared to a multi-threaded CPU-based cache, because it avoids performance overheads associated with multiple threads having to synchronize with each other to realize they are about to start a stampede.

The switch presumably also has multiple cores which still need to do this work, no? Or is the claim that moving this synchronization to the router behind a network hop saves CPU cycles on the app server?

The relevant part of the switch hardware described by the OrbitCache paper doesn't have typical processor cores. Instead it is an "RMT" pipeline.

I wrote a brief description of RMT here: https://danglingpointers.substack.com/p/scaling-ip-lookup-to...