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Date: Wed, 13 Jun 2012 14:40:28 -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 6/10/2012 8:45 PM, 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.

I think this commit contains a typo: "events" should be "revents". 
(context->wake_up_rec.events is always nonzero at this point in the 
code, so it makes no sense to test that.)  As a result, 
g_wakeup_acknowledge() is being called much more often than necessary. 
I think this could easily explain the performance problems that have 
been reported, but I won't have a chance to test this on my (slow) XP 
system for a while, and possibly not until tomorrow.

Ken

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