Linux epoll remains the backbone of high-performance network servers, yet many developers only scratch the surface of its API. This deep dive examines how epoll works under the hood—from the eventpoll structure and ready list to the subtle differences between edge-triggered and level-triggered modes. We also look at real-world usage patterns, including how to avoid thundering herds, manage file descriptor lifecycles, and tune performance for millions of concurrent connections. While the original article is in Chinese, the concepts translate directly to any language's networking stack. For engineers building chat servers, game backends, or API gateways, understanding epoll's internals can prevent subtle bugs and unlock significant performance gains. This guide distills the key insights without copying the source code, offering a practical reference for both learning and production debugging.
Explore Linux epoll from kernel internals to practical event-loop patterns, covering edge vs level triggering, performance trade-offs, and common pitfalls.