sleepy_penguin - Linux I/O events for Ruby

sleepy_penguin provides access to newer, Linux-only system calls to wait on events from traditionally non-I/O sources. Bindings to the eventfd, timerfd, inotify, and epoll interfaces are provided. Experimental support for kqueue on FreeBSD (and likely OpenBSD/NetBSD) is also provided.


  • Thread-safe blocking operations for all versions of Matz Ruby

  • IO-like objects are backwards-compatible with

  • High-level Epoll interface is fork-safe and GC-safe

  • Unlike portable event frameworks, the Linux-only epoll interfaces allow using edge-triggered or one-shot notifications for possibly improved performance. Likewise, the kqueue interface supports one-shot notifiactions, too.

  • Fully-documented and user-friendly API


If you're using a packaged Ruby distribution, make sure you have a C compiler and the matching Ruby development libraries and headers.

If you use RubyGems:

gem install sleepy_penguin

Otherwise grab the latest tarball from:

Unpack it, and run “ruby setup.rb”


You can get the latest source via git from the following locations: (mirror)

You may browse the code from the web and download the latest snapshot tarballs here:

Inline patches (from “git format-patch”) to the mailing list are preferred because they allow code review and comments in the reply to the patch.

We will adhere to mostly the same conventions for patch submissions as git itself. See the Documentation/SubmittingPatches document distributed with git on on patch submission guidelines to follow. Just don't email the git mailing list or maintainer with sleepy_penguin patches.


All feedback (bug reports, user/development discussion, patches, pull requests) go to the mailing list: [email protected]

  • Mailing list archives:

  • Also available over NNTP: nntp://