should we use QT_NO_GLIB=1 like kwin?

[Milian Wolff]

On Wednesday 06 October 2010 23:03:30 Aleix Pol wrote:
> On Wed, Oct 6, 2010 at 10:51 PM, Milian Wolff <mail at milianw.de> wrote:
> > Hey all,
> > 
> > since I spent some time today to investigate the excessive wakeups of
> > KDevelop
> > while it's supposedly doing *nothing* I got a suggestion by pinotree in
> > #kde-devel:
> > 
> > He proposed to use QT_NO_GLIB for KDevelop. Indeed that removes most
> > calls to
> > poll() when comparing a strace -tt -p $(pidof kdevelop).
> > 
> > See e.g. here how to implement:
> > 
> > 
> > http://websvn.kde.org/trunk/KDE/kdebase/workspace/kwin/main.cpp?revision=
> > 1177865&view=markup search for QT_NO_GLIB.
> > 
> > It's very easy and for kwin it also fixed high CPU usage bugs. Didn't we
> > have
> > some like these as well?
> > 
> > Anyhow, the draw back would be: It's not possible to use gstreamer or
> > phonon
> > in KDevelop anymore as these require that glib eventloop. I personally
> > don't
> > see a reason (now) for using phonon in KDevelop. In the far future one
> > might
> > want to play screencasts or other media in embedded documentation...
> > 
> > So what do you guys think: Should we try it out? Or leave it as-is?
> > 
> > Bye

> As I said on the IRC I wouldn't be against it but I'd like to make it sure
> that we _need_ that to work properly. Isn't there a reason for these poll
> calls for instance? If you open a small app and leave it open it doesn't
> take CPU constantly, at least...

Ah indeed, I didn't make that clear in my first mail:

1) according to powertop the wakeups are not noticeably less with QT_NO_GLIB
2) there are still quite a few stats etc. going on according to strace which 
I'll investigate sooner or later.

It's just that pinotree (someone whom I trust code-wise) suggested it and that 
kwin already uses it... I hoped for a freebee...
-- 
Milian Wolff
mail at milianw.de
http://milianw.de
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