Agent Substrate is a secure agent execution runtime designed to run millions of sandboxes with high density, supporting sub-500ms resume operations and native zero-trust isolation. Built on Kubernetes, it multiplexes idle agent applications onto shared workers and supports multiple sandbox technologies including microVMs and gVisor. The system enables framework-agnostic deployment of AI agents and stateful applications with persistent state across suspend/resume cycles.
epoll and kqueue are kernel APIs that enable efficient I/O multiplexing by registering interest in file descriptors once rather than repeatedly polling them, making high-concurrency servers feasible by reducing CPU overhead from O(n) scanning to O(activity).