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Date: Mon, 11 Jun 2012 11:10:58 -0400
From: Ken Brown <kbrown AT cornell DOT edu>
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Subject: Re: Performance problems with emacs-X11 in current cygwin
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On 6/11/2012 7:39 AM, Ken Brown wrote:
> On 6/10/2012 10:54 PM, Yaakov (Cygwin/X) wrote:
>> On 2012-06-10 19:45, Ken Brown wrote:
>>> The bisection shows that the first problematic commit is this one:
>>>
>>> http://git.gnome.org/browse/glib/commit/?h=glib-2-32&id=7eae486179e2799c369ed9ffcea663bf9161ce79
>>>
>>>
>>>
>>>
>>> Author: Ryan Lortie <desrt AT desrt DOT ca>
>>> Date: Wed Aug 31 22:07:02 2011 -0400
>>>
>>> GMain: simplify logic for g_wakeup_acknowledge()
>>>
>>> Instead of messing around with context->poll_waiting, just look at the
>>> GPollFD to see if the GWakeup needs to be acknowledged.
>>>
>>> In case anyone else wants to confirm this, you can get my glib builds by
>>> running
>>>
>>> setup.exe -K http://sanibeltranquility.com/cygwin/kbrown.gpg
>>>
>>> and adding http://sanibeltranquility.com/cygwin to the list of mirrors.
>>> The problematic version is
>>>
>>> libglib2.0_0-2.30.90_7eae4861-1
>>>
>>> and the preceding version (without the problem) is
>>>
>>> libglib2.0_0-2.30.90_87880df-1
>>>
>>> I've tested the latter with emacs-23, emacs-24, and gvim.
>>
>> Thanks for doing this. Is this still only a problem with XP? If so, it
>> is most likely a bug in Cygwin itself.
>
> It's a problem with XP but not with Windows 7. No one has reported
> testing other systems.
>
> Do you understand the code well enough to make a test case to help cgf
> and Corinna debug it, assuming it's a Cygwin bug?

BTW, there's no easy way to revert the problematic commit, in view of 
this commit, which came on the next day:

http://git.gnome.org/browse/glib/commit/?h=glib-2-32&id=1c8c408c51c85230356cc95c06f2e1bd3f376624

The commentary that goes with that commit gives some explanations of 
what's supposed to happen.  It doesn't mean much to me, because of my 
ignorance of how glib works.  But maybe it will give you an idea where 
to look.

Ken


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