Re: Multi-threaded UI Freezes on GDK Call

["Michael R. Head" <burner suppressingfire org>]

On Tue, 2007-12-18 at 17:14 -0500, Michael R. Head wrote:
> On Tue, 2007-12-18 at 16:45 -0500, Michael McCann wrote:
> > I've got a multithreaded GTK application. One thread runs gtk_main():
> >
> > gtk_threads_enter();
> > gtk_main();
> > gtk_threads_leave();
>
> I assume you meant
>
>
>     g_threads_init();
>     gdk_threads_init();
>     gtk_init();
>     
>     gdk_threads_enter();
>     gtk_main();
>     gdk_threads_leave();
>
> right?

> > The other thread is an infinite loop that sleeps for one second on each 
> > loop. Every x seconds, the infinite loop calls a function, which makes 
> > some GDK calls. At the beginning of this function, gdk_threads_enter() 
> > is called; at the end, gdk_flush() and gdk_threads_leave() is called.
> >
> > Whenever this function is called, the UI freezes and CPU usage jumps to 
> > 100% for about one second (no other applications freeze, of course). 
> > I've tried calling gdk_threads_leave()/enter() before and after each GDK 
> > call to no avail. I run g_thread_init() and gdk_threads_init() at the 
> > beginning of my program.

Does your special function take time to do its job? If so, then that
would be why. For example:

...
while(1) {
gdk_threads_enter();
sleep(1)
gdk_threads_leave();
sleep(10)
};
...

you'd freeze your app for a second every 10 seconds.


> > In the function, gdk_screen_get_default(), gdk_screen_get_root_window(), 
> > gdk_pixbuf_get_from_drawable(), and gdk_pixbuf_save_to_bufferv() are 
> > called.
> >
> > I'm using NetBSD on a P4 1.2GHz. What am I doing wrong? I've asked this 
> > question on IRC (irc.gnome.org, #gtk+) but noone seems to know the problem.
> > _______________________________________________
-- 
Michael R. Head <burner suppressingfire org>
http://www.suppressingfire.org/~burner/
http://suppressingfire.livejournal.com