XCreatePixmapCursor stats a lot of files...

[Lubos Lunak]

On Tuesday 02 of October 2007, BJörn Lindqvist wrote:
> On 10/2/07, Lubos Lunak <l.lunak at suse.cz> wrote:
> > On út 2. října 2007, Glynn Clements wrote:
> > > No, it's a bug, insofar as it contradicts the documentation of
> > > XCreatePixmapCursor() as well as existing behaviour. Also, it appears
> > > that there is no way to override it and *force* Xlib to do what it's
> > > told.
> >
> > ...
> >
> > > >  The fact that the cursor theming is pretty inefficient is a
> > > > different matter though :(.
> > >
> > > The inefficiency isn't the problem. The fact that it's happening at
> > > all is the problem. If the client tells Xlib to use a specific pixmap
> > > and mask as the cursor, Xlib should damn well do what it's told, not
> > > ignore the client and use some other cursor.
> >
> >  So you actually got some other cursor than you asked for? I shouldn't
> > think
>
> It should be pretty easy to inject a different cursor by writing
> appropriate data to
> /usr/share/pixmaps/Human/cursors/00000000000000000000000000000000 for
> example for the strace I posted.

 Which is exactly the intention I'd say. If somebody wants that.

> > so, I'd expect that in your specific case it did exactly what you
> > expected, minus some hidden inefficiency which, as you say, isn't a
> > problem for you.
>
> Which apps are helped by this feature?

 Yours, if you use XCreatePixmapCursor? Or any other apps which still use it?

> AFAICT, no GNOME apps use it. 
> Why can't those apps that rely on this behavior be fixed? Surely,
> calling XCreatePixmapCursor() and expect to get a themed cursor cannot
> be the canonical way to do it, can it?
>
> And the inefficiency is a real problem for me. 150 ms on a decent
> laptop easily becomes seconds on low-end hardware if you have other
> processes and disk activity running. What if your home directory is
> mounted on a NFS share when XCreatePixmapCursor() goes looking in
> ~/.icons? Even more overhead.

 Welcome to the world of current Linux desktop :-/ - is this the only problem 
you have with performance? You're presumably going to have this performance 
impact anyway because of searching for standard X cursors.

-- 
Lubos Lunak
KDE developer
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