# Rev 0.3.1: a libev-based event framework, now with better filesystem monitoring **URL:** \ **Category:** Ruby\ **Created:** [October 15, 2009, 6:15am UTC](https://www.ruby-forum.com/t/rev-0-3-1-a-libev-based-event-framework-now-with-better-filesystem-monitoring/177335 "2009-10-15T06:15:57Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![murfhy](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/d26b3c/32.png) [@murfhy](https://www.ruby-forum.com/u/murfhy)\ **Post date:** [October 15, 2009, 6:15am UTC](https://www.ruby-forum.com/t/rev-0-3-1-a-libev-based-event-framework-now-with-better-filesystem-monitoring/177335/1 "2009-10-15T06:15:57Z")
rev 0.3.1 is largely a maintenance/bugfix release, but it comes with a new feature: configurable filesystem polling intervals. The previous version introduced Rev::StatWatcher, a simple observer that notifies you if stat() for a given path changes. Thanks to rev’s libev-based core, rev can do this while monitoring for events on any Ruby IO object, and all in a single thread. On Linux, filesystem monitoring uses inotify, a high-performance interface which receives event notifications directly from the kernel. On all other platforms, libev monitors the filesystem using stat() polling. The previous version did not allow you to configure this polling interval, and used a “default” of approximately 5 seconds intended to maximize performace. This is unacceptable in some cases where you want filesystem monitoring closer to realtime. 0.3.1 lets you create new filesystem watchers with a prespecified polling interval: Rev::StatWatcher.new("./path/to/interesting/file", 0.5) This will check the status of the given path every 0.5 seconds rather than every 5 seconds. Values below 0.1 are not particularly meaningful. On Linux the polling interval is ignored and events are received as soon as inotify reports them.