Details
Major Description
The RPC server listener loops accepting connections, distributing the new connections to socket readers, and then conditionally & periodically performs a scan for idle connections. The idle scan choses a random index range to scan in a synchronized linked list.
With 20k+ connections, walking the range of indices in the linked list is extremely expensive. During the sweep, other threads (socket responder and readers) that want to close connections are blocked, and no new connections are being accepted.