Re: Performance problems with emacs-X11 in current cygwin

[Ken Brown <kbrown at cornell dot edu>]

On 6/14/2012 3:18 PM, Ryan Johnson wrote:
> On 13/06/2012 5:40 PM, Christopher Faylor wrote:
> > On Wed, Jun 13, 2012 at 05:07:17PM -0400, Ken Brown wrote:
> > > On 6/13/2012 2:40 PM, Ken Brown wrote:
> > > > 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@desrt.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.
> > > I've confirmed that fixing the typo solves the problem on my XP system.
> > > I suspect that this issue is not specific to XP after all and has more
> > > to do with the slowness of the machine, so that the performance problem
> > > is more noticeable. In any case, it's clearly a glib bug.
> > >
> > > I've filed a bug report upstream:
> > >
> > > https://bugzilla.gnome.org/show_bug.cgi?id=678052
> > What incredible perseverence you've shown in tracking this down. Bravo!
> ++
>
> Amazing. This is one of the nastier kinds of bugs I've seen anybody
> track down...

Thanks.  I actually enjoyed learning some new things, though it was 
frustrating at times.

Ken


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