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

[Sebastien Vauban]

Eli Zaretskii <eliz@gnu.org> writes:
>> From: Sebastien Vauban <sva-news@mygooglest.com>
>> Cc: 20927@debbugs.gnu.org
>> Date: Tue, 30 Jun 2015 10:30:02 +0200
>> 
>> >> 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.
>> >
>> > Probably because you use glib's notifications,
>> 
>> If you say so (I'm not even aware of what that is)...
>
> It's a library which implements file notifications.
>
>> Would you advice me to put:
>> 
>> --8<---------------cut here---------------start------------->8---
>>   ;; Don't use file notification functions.
>>   (setq auto-revert-use-notify nil)
>> --8<---------------cut here---------------end--------------->8---
>> 
>> just for Cygwin Emacs (where the problem was visible)
>
> Since Ken cannot reproduce this in his Emacs, I'd suggest to try and
> figure out why you are hit by this problem, while he is not.

That stays a mystery.

> For starters, does the problem happen in "emacs -Q"?

I guess not. I should try to get a recipe for reproducing it from
emacs -Q, that's right.

> If so, I suggest to compare the versions of glib you and Ken use.

I use his Cygwin Emacs package (now, 24.5.2). Dunno about glib versions.

>> or for both Windows and Cygwin Emacs?
>
> No, the native Windows build of Emacs doesn't use glib (it can be
> built like that, but when I tried this, file notifications simply
> didn't work at all).  It uses a native Windows API for receiving file
> notifications.  So this is definitely not needed in the native Windows
> build.

Thanks for this precision.