Epoll vs. Io_uring in Linux
4 hours ago
- #Linux
- #Performance
- #Asynchronous I/O
- The article discusses transitioning from epoll to io_uring for asynchronous I/O handling in Linux, driven by performance improvements in a reverse proxy project.
- Epoll requires multiple syscalls per I/O event (e.g., epoll_ctl, epoll_wait, read/write), leading to context switch overhead, especially under high connection loads.
- io_uring uses shared memory ring buffers for submissions and completions, reducing syscall overhead to batches or nearly zero with SQPOLL, shifting work to the kernel.
- Key io_uring features include zero-copy I/O via buffer registration and SEND_ZC for networks, though SQPOLL may consume CPU with a polling kernel thread.
- The author recommends io_uring over epoll for modern Linux systems (kernel v5.1+), citing architectural advantages and performance gains.