Hi Gelin, Apparently in the twisted 10.2 / python 2.7 combination in which the bug occurs only rarely (every couple of weeks) I am still using twisted’s epoll: epollreactor.py: from twisted.python import _epoll From: twisted-python-bounces@twistedmatrix.com [mailto:twisted-python-bounces@twistedmatrix.com] On Behalf Of Gelin Yan Sent: Tuesday, May 28, 2013 9:09 PM To: Twisted general discussion Subject: Re: [Twisted-Python] any progress for Ticket #6346, #6378? On Wed, May 29, 2013 at 10:37 AM, Alec Matusis wrote: Hi Gelin,

As I know there are two epoll implementations in twisted, one that from twisted itself and another one comes from standard library since py 2.6. I was slightly incorrect in my email: the combination where it happens infrequently is actually Twisted 10.2 with python 2.7.3 (not Twisted 10.1 as I wrote). How can I check whether twisted is using Python’s epoll or its own in this combination? And how can I switch between epoll implementations in my app?

Alec From: Gelin Yan [mailto:dynamicgl@gmail.com] Sent: Tuesday, May 28, 2013 6:42 PM To: Alec Matusis Subject: Re: [Twisted-Python] any progress for Ticket #6346, #6378? On Wed, May 29, 2013 at 8:31 AM, Alec Matusis wrote:

  By reading these comments, It looks like recent version of twisted may suffer from this problem. So what version of twisted should  I use? Do I need to keep using 10.1? This problem is very frequent on Linux with Python 2.7 / Twisted 12 combination (we had to quickly roll back- cannot operate with that combo).

It never happened with Python 2.6 / Twisted 10 (as in years). It happens very infrequently with Python 2.7 / Twisted 10.1 (as 1x in weeks) Right now I have a server in this state on Python 2.7 / Twisted 10.1. It refuses 30% of new connections, spewing this error: 2013-05-28 17:28:25-0700 [twisted.internet.protocol.ServerFactory] Unhandled Error         Traceback (most recent call last):           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/python/log.py", line 69, in callWithContext             return context.call({ILogContext: newCtx}, func, *args, **kw)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/python/context.py", line 59, in callWithContext             return self.currentContext().callWithContext(ctx, func, *args, **kw)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/python/context.py", line 37, in callWithContext             return func(*args,**kw)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/epollreactor.py", line 217, in _doReadOrWrite             why = selectable.doRead()         --- <exception caught here> ---           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/tcp.py", line 938, in doRead             transport = self.transport(skt, protocol, addr, self, s, self.reactor)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/tcp.py", line 752, in __init__             self.startReading()           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/abstract.py", line 365, in startReading             self.reactor.addReader(self)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/epollreactor.py", line 100, in addReader             self._add(reader, self._reads, self._writes, self._selectables, _epoll.IN, _epoll.OUT)           File "/usr/local/encap/Python-2.7.3/lib/python2.7/site-packages/Twisted-10.2.0-py 2.7-linux-x86_64.egg/twisted/internet/epollreactor.py", line 88, in _add             self._poller._control(cmd, fd, flags)           File "_epoll.pyx", line 125, in _epoll.epoll._control         exceptions.IOError: [Errno 2] No such file or directory If I restart the server, it will be stable for a couple of weeks, until some event triggers this problem again. We hope that this problem is fixed before we are really forced to migrate to newer Python, otherwise there's no real upgrade path for us using Twisted. From: twisted-python-bounces@twistedmatrix.com [mailto:twisted-python-bounces@twistedmatrix.com] On Behalf Of Gelin Yan Sent: Saturday, May 25, 2013 7:51 AM To: Twisted general discussion Subject: Re: [Twisted-Python] any progress for Ticket #6346, #6378? On Sat, May 25, 2013 at 3:22 AM, wrote: On 04:21 pm, dynamicgl@gmail.com wrote:

Hi All

   I am quite concerned about these two tickets due to recently I may port one of my systems to Ubuntu. Perhaps you can help out with the tickets, then!  As hopefully you've noticed, one of them is currently up for review.  This means a developer believes a fix for the problem has been created and is just waiting for someone else to look it over and agree that it should be applied to

Hi Gelin, I don't have anything extra to add about the status of those two tickets (I think you meant #6373 rather than #6378, by the way) - which is exactly why I'm replying. Twisted development doesn't take place in secret.  The issue tracker should always reflect the latest state of the development process.  If an issue has had no comments and a branch no commits for a couple months, then it's almost certainly because no one has worked on the issue for a couple months. So you generally don't need to ask if there has been any progress, because progress will always be reflected in ticket history or in version control. trunk.  If this happens, then the fix will be available in the next release of Twisted, 13.1.0, which will probably happen in just a few weeks. For more details about how the review process works, please take a look at this wiki page:     http://twistedmatrix.com/trac/wiki/ReviewProcess Jean-Paul

  By reading these comments, It looks like recent version of twisted may suffer from this problem. So what version of twisted should  I use? Do I need to keep using 10.1?

 I always use the latest version on windows.

Regards

gelin yan

Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python Hi exarkun     I noticed "review" tag has been removed for a while so does it imply this ticket is still pending?     I am not quite familiar how epoll works on linux so my help probably can be neglected. I event can't sure how to reproduce this bug.    By the way, Is it possible to use the "old" epoll implementation instead of the built in epoll from python with the latest version? It looks like this old one works quite well.  Thanks Regards gelin yan  Hi Alec    Thanks for your info. As I know there are two epoll implementations in twisted, one that from twisted itself and another one comes from standard library since py 2.6. If I was correct, since 10.2, twisted has been used the standard epoll if applicable. I am curious which one did you use? Have you tried py 2.7 & epoll from twisted itself? Regards gelin yan Hi Alec   there is a link: http://twistedmatrix.com/trac/browser/tags/releases/twisted-13.0.0/twi sted/internet/epollreactor.py I strip the related part and paste here: try:   from select import epoll except ImportError:   from twisted.python import _epoll in the latest trunk  there is only  from select import epoll. I am not sure which one you are using. epoll has been available in standard library since Py 2.6. Twisted has been used its own epoll wrapper for years until recently. Regards gelin yan

Can you please not quote the whole email in your reply? I have to scroll through pages and pages of text to reach the section you wrote. I realize GMail hides it by default, but I am not using GMail. -Itamar