bug#20927: 24.5; Cygwin Emacs completely blocks for 5+ seconds

[Sebastien Vauban <sva-news-D0wtAvR13HarG/iDocfnWg@public.gmane.org>]

Ken Brown <kbrown-HmMyXyqgL2CVc3sceRu5cw@public.gmane.org> writes:
> On 6/29/2015 9:21 AM, Sebastien Vauban wrote:
>> When:
>>
>> 1. Starting Cygwin Emacs,
>> 2. Opening whichever local file (`org-mode/lisp/org.el', in my case),
>>     and
>> 3. Keeping constantly our index on the Down arrow key to make the buffer
>>     scroll indefinitely,
>>
>> Emacs blocks (after 30 seconds scroll or so) for 5 entire seconds, and
>> then revives...
>
> I can't reproduce this on my system.  I held my finger on the down arrow for
> about 2 minutes.

Weird... I can reproduce that quite easily, and Emacs pauses almost on
the same lines each time.

If you're interested, I can make a video of it.

>> I've tracked down this problem in Cygwin Emacs, and it's due to this
>> line:
>>
>> --8<---------------cut here---------------start------------->8---
>>    (global-auto-revert-mode 1)           ; Auto refresh buffers.
>> --8<---------------cut here---------------end--------------->8---
>>
>> When it's commented, Cygwin Emacs behaves normally.
>>
>> Note the above line does NOT cause any trouble in Windows Emacs...
>
> One difference is that Cygwin Emacs uses gfilenotify, based on GLib.  I recall
> a discussion some time ago (either on emacs-devel or in a bug report) about
> problems with gfilenotify, but I don't remember if the problems were resolved.

That seems to still be the problem -- see next post.