Many existing userland network daemons suffer from a performance curve that severely degrades under overload conditions to the point of collapse. The design of AIO was such that it should maintain a steady response rate when faced with a multitude of outstanding connections. With AIO for Linux becoming ready for more widespread use, the real world performance characteristics of the design and its shortcomings needs to be examined. What follows is an attempt to characterise the behaviour of async poll and read under various conditions, contrasting with poll(), and /dev/epoll.

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