# Announcing Rev: a high performance event library for Ruby 1.9 **URL:** \ **Category:** Ruby\ **Created:** [December 26, 2007, 5:47am UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178 "2007-12-26T05:47:44Z")\ **Posts on this page:** 7\ **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:** [December 26, 2007, 5:47am UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/1 "2007-12-26T05:47:44Z")
Hello everyone, I’ve just made my initial public release of Rev, a high performance event library for Ruby 1.9 built on top of libev. Events are monitored with advanced system calls including epoll on Linux, kqueues on BSD, and event ports on Solaris. You can read more about libev here: [http://software.schmorp.de/pkg/libev.html](http://software.schmorp.de/pkg/libev.html) The release has not yet reached the gem mirrors, so you can grab it here for the time being: [http://rev.rubyforge.org/releases/gems/rev-0.1.0.gem](http://rev.rubyforge.org/releases/gems/rev-0.1.0.gem) Rev gives you the ability to monitor Ruby IO objects for readability and/or writability. It also lets you configure either one-shot or periodic timers. Future plans include wrappers for monitoring signals as well as filesystem events. Rev makes use of a number of new Ruby 1.9 features, namely the ability to do blocking calls inside of native threads using the rb\_thread\_blocking\_region() function. The entire event loop is written with scalability in mind, with nearly constant time overhead compared to the number of events being monitored, at least on Linux, FreeBSD, or Solaris. In addition to a C extension which provides Ruby bindings to libev, Rev also provides asynchronous observer-like wrappers for Ruby’s core socket classes using the new Ruby 1.9 \*\_nonblock methods. It also provides asynchronous DNS resolution for the purpose of making outgoing connections. You can view the RDoc here: [http://rev.rubyforge.org/](http://rev.rubyforge.org/) Enjoy! ---
**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:** [December 28, 2007, 10:06pm UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/2 "2007-12-28T22:06:17Z")
- Tony A. (removed\_email\_address@domain.invalid) wrote: > I’ve just made my initial public release of Rev, a high performance > event library for Ruby 1.9 built on top of libev. Events are monitored > with advanced system calls including epoll on Linux, kqueues on BSD, > and event ports on Solaris. Yum, thanks 🙂 Buffered writing seems to be broken; the buffer is sliced incorrectly, so it spins writing the last few KB, and the Watcher doesn’t have an enabled? method so that fails if it ever reaches it. Patch: [http://voi.aagh.net/rev-0.1.0\_lib-rev-buffered\_io.rb.diff](http://voi.aagh.net/rev-0.1.0_lib-rev-buffered_io.rb.diff) Few other issues: spurious closed connections - if I do one big write I’m ok, but splitting a 500k buffer into 4k writes almost always results in a closed stream IOError on the second write, and a ECONNRESET on the reading side. Servers don’t serve much; they serve one client and exit even in the exception-free case, including the example echo server. Multiple clients will be served if they manage to connect before the rest close, but once the listen queue’s empty Rev::Loop#run returns. This is tested with FreeBSD 6.2, using kqueue, select and poll. ---
**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:** [December 29, 2007, 12:19am UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/3 "2007-12-29T00:19:25Z")
On Dec 28, 2007 2:05 PM, Thomas H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Buffered writing seems to be broken; the buffer is sliced incorrectly, > so it spins writing the last few KB Heh, I caught that one earlier today and a fix is checked in. Thanks for pointing it out. > and the Watcher doesn’t have an enabled? method so that fails if it ever > reaches it. Patch: > > [http://voi.aagh.net/rev-0.1.0\_lib-rev-buffered\_io.rb.diff](http://voi.aagh.net/rev-0.1.0_lib-rev-buffered_io.rb.diff) Thanks, I’ll get that addressed as well. You might notice the painful lack of tests… I’d like to use RSpec but that’s unfortunately broken by 1.9changes at the moment. Perhaps I could use Rubinius’s minispec if that’s working on 1.9, but my guess is I’ll have to end up using Test::Unit for the time being. > Few other issues: spurious closed connections - if I do one big write > I’m ok, but splitting a 500k buffer into 4k writes almost always results > in a closed stream IOError on the second write, and a ECONNRESET on the > reading side. I may have a fix for that shortly… I’ll ping you off list if I do > Servers don’t serve much; they serve one client and exit even in the > exception-free case, including the example echo server. Multiple > clients will be served if they manage to connect before the rest close, > but once the listen queue’s empty Rev::Loop#run returns. > This is tested with FreeBSD 6.2, using kqueue, select and poll. Bizzare. I don’t presently have a FreeBSD system, although I plan on installing FreeBSD later tonight actually, so I can test there. I’m using kqueue on MacOS X and have not experienced that problem, nor have I experienced the problem with Linux/epoll. I’m curious how that’s even happening as the listen socket should be open and the Rev::Listener object should still be attached to the loop. ---
**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:** [December 29, 2007, 7:13pm UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/4 "2007-12-29T19:13:59Z")
On Dec 28, 2007 6:21 PM, Thomas H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > mspec seems to work. After changing target in mspec/scripts/mspec.rb > from shotgun/rubinius to ruby19, I can do: > > -% ruby19 bin/mspec spec/core/fixnum/\* > Started > …F… (etc) Nice, I’ll get that installed… I just tried on my laptop which is running Ubuntu; behavior’s identical > to FreeBSD with epoll and select. > Further testing shows this doesn’t happen if I use small writes, so it > seems to be related to buffering. I can’t see any immediately obvious > reason why, though. Running off the svn trunk version of Rev I get: rev/lib/rev/buffered\_io.rb:44:in `write_nonblock': Resource temporarily unavailable (Errno::EAGAIN) rev/lib/rev/buffered_io.rb:44:in `write’ Which should be relatively trivial to fix. That exception can probably be safely swallowed, although that may not be the greatest thing from a performance perspective. If you try the version of Rev in trunk do you get the same thing? ---
**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:** [December 29, 2007, 8:58pm UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/5 "2007-12-29T20:58:55Z")
On Dec 29, 2007 11:13 AM, Tony A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Running off the svn trunk version of Rev I get: > > rev/lib/rev/buffered\_io.rb:44:in `write_nonblock': Resource temporarily unavailable (Errno::EAGAIN) rev/lib/rev/buffered_io.rb:44:in `write’ > > Which should be relatively trivial to fix. That exception can probably be > safely swallowed, although that may not be the greatest thing from a > performance perspective. Yeah, that’s a bit of a snag. Do you know how to do a nonblocking write that swallows that exception and gets the return value from write(2)? ---
**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:** [December 29, 2007, 2:22am UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/6 "2007-12-29T02:22:14Z")
- Tony A. (removed\_email\_address@domain.invalid) wrote: > Thanks, I’ll get that addressed as well. You might notice the painful > lack of tests… I’d like to use RSpec but that’s unfortunately broken > by 1.9changes at the moment. Perhaps I could use Rubinius’s minispec > if that’s working on 1.9, but my guess is I’ll have to end up using > Test::Unit for the time being. mspec seems to work. After changing target in mspec/scripts/mspec.rb from shotgun/rubinius to ruby19, I can do: -% ruby19 bin/mspec spec/core/fixnum/\* Started …F… (etc) > > Few other issues: spurious closed connections […] > > I may have a fix for that shortly… I’ll ping you off list if I do Thanks. > > Servers don’t serve much; they serve one client and exit even in the > > exception-free case, including the example echo server. Multiple > > clients will be served if they manage to connect before the rest > > close, but once the listen queue’s empty Rev::Loop#run returns. > > Bizzare. I don’t presently have a FreeBSD system, although I plan on > installing FreeBSD later tonight actually, so I can test there. I just tried on my laptop which is running Ubuntu; behavior’s identical to FreeBSD with epoll and select. Also, :backend =\> :kqueue makes it crash horribly there 😉 > I’m using kqueue on MacOS X and have not experienced that problem, nor > have I experienced the problem with Linux/epoll. > > I’m curious how that’s even happening as the listen socket should be > open and the Rev::Listener object should still be attached to the > loop. Further testing shows this doesn’t happen if I use small writes, so it seems to be related to buffering. I can’t see any immediately obvious reason why, though. ---
**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:** [January 1, 2008, 9:01pm UTC](https://www.ruby-forum.com/t/announcing-rev-a-high-performance-event-library-for-ruby-1-9/124178/7 "2008-01-01T21:01:59Z")
On Dec 29, 2007 12:57 PM, Tony A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Yeah, that’s a bit of a snag. Do you know how to do a nonblocking write > that swallows that exception and gets the return value from write(2)? I released Rev 0.1.1 (should be available through the gem servers now) which resolves these problems, and also bundles an asynchronous HTTP client. Give it a try and let me know if it fixes your problems.