On Tue, Aug 02, 2005 at 07:47:32AM -0400, Owen Taylor wrote: > On Sun, 2005-07-31 at 15:44 -0600, Pat Mahoney wrote: > > (not subscribed; please CC replies) > > > > I'm trying to find a way to provide my mainloop with asynchronous data > > from a thread. I have read this: > > > > http://mail.gnome.org/archives/gtk-app-devel-list/2004-July/msg00181.html > > > > which describes how to use a GAsyncQueue and GSource to watch the queue > > for available data (and to have the thread wake up the mainloop when data > > is available). A callback is run in the context of gtk_main when > > data is available. It works perfectly except for one show-stopper > > problem: > > Note that using a custom GSource here is perhaps overcomplicated. The > simplest method is: > > g_idle_add (function_to_call_in_main_thread, data_to_pass_to_function); > > (Or use g_idle_add_full() if you want to prioritize the callback higher > than the default idle priority.)
Yes, that is simplest. In my case, the CPU usage jumps to 100% (though the app is still responsive). My particular app is reading frames from one or more webcams (select() doesn't work with video4linux devices, so this must be done in a seperate thread or process). The camera_thread is triggered by the mainloop to snap a picture which it pushes onto a GAsyncQueue. My callback on_camera_frame_available() checks the queue and returns immediately if there is no data. Similarly, the GSourceFuncs check the queue. However, by using the GSource, the check is performed about 2-3 times per frame (using printf() to watch that, so timing may be skewed), while the g_idle_add() method runs my callback continually, and so the GAsyncQueue is constantly being checked for data, sucking down the CPU. -- Pat Mahoney <[EMAIL PROTECTED]> _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
