Epoll

lastmod 2019-10-06created 2014-05-1310 edits

epoll is a Linux kernel system call, a scalable I/O event notification mechanism, first introduced in Linux kernel 2.5.44.[1] It is meant to replace the older POSIX select(2) and poll(2) system calls, to achieve better performance in more demanding applications, where the number of watched file descriptors is large (unlike the older system calls, which operate in O(n) time, epoll operates in O(1) time[2]). epoll is similar to FreeBSD's kqueue, in that it operates on a configurable kernel object, exposed to user space as a file descriptor of its own.

See also

• Input/Output
• kqueue
• IOCP
• Overlapped IO
• libevent
• Context switch

Favorite site

• Wikipedia (en) article on epoll
• Joinc: epoll - based on kernel 2.4
• epoll explained in C
• GpgStudy - Is epoll really that great?
• epoll translation
• Advanced I/O model: the epoll() function
• [Recommended] (C) epoll explained ¹
• Basic concepts and usage of Epoll

References