Epoll's Handle-Centric Design vs. Kqueue's Filter-Centric Design (2021)

4 hours ago

The article discusses the technical debt associated with BSD's kqueue compared to Linux's epoll.
Originally, IRCDs used select for polling sockets, which had scalability issues due to design defects.
The poll syscall was introduced as a more efficient alternative to select, addressing some scalability issues.
kqueue was introduced in FreeBSD in 2000 as a kernel-assisted event notification system, supporting various event filters.
epoll was introduced in Linux in 2002, offering a composable design that monitors kernel handles.
The key difference between kqueue and epoll is that kqueue operates on event filters, while epoll focuses on kernel handles.
epoll's composable design allows it to monitor any kernel resource without modification, making it more flexible.
FreeBSD has started adopting Linux-like features, such as eventfd, indicating a potential shift in kqueue's design.

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