[Twisted-Python] Strange behaviour for epoll reactor

[Jean-Paul Calderone]

On Tue, 11 Dec 2007 15:06:45 +0200, Mustafa Sakalsiz <sakalsiz at gmail.com> wrote:
>We have a twisted application uses the epoll reactor. Sometimes it
>wastes %100 cpu. It has also some threads for single isolated
>functions (using deferToThred). First we suspected that threads don't
>end and goes to an infinite loop. Because application still accepts
>connections and executes the requested functions. Then I ran the
>following ps command
>
>ps h -Leo pid,pcpu,args,lwp
>
>Looking at the output, the main thread seemed to be wasting the whole
>cpu time. Later on I attached the process to the strace and saw the
>output below. I don't how does it happen or when does it happen. It is
>not regular nor repeatable, but this is the strace output when it gets
>into loop. I send to the list, because it may be useful for someone.
>
>Now we switched back to the select reactor.
>
>P.S.: We use perspective broker on the server side and qt4reactor for
>the client.

This sounds like this issue:

  http://twistedmatrix.com/trac/ticket/2809

This is fixed in current trunk at HEAD and the fix will be included in the
next release of Twisted.

Jean-Paul