On Mon, Jun 23, 2008 at 07:11:40PM +0200, Eirik Byrkjeflot Anonsen wrote: > Keith Packard <keithp@xxxxxxxxxx> writes: > >> I believe it was a performance hack for web pages with several layers > >> of partial transparency. At the time we had an evil test case which > >> saw great speed-up with this hack. If the shm stuff isn't available, > >> I'm sure we'll revert to ordinary rendering (that's basically what the > >> "error" message is about). So nothing should break. > > > > Please let us know precisely what performance problem you're working > > around so we can fix it. > > > > Drawing lots of images with alpha-blending on top of each other was > slow :) > > This was several years ago, and I wasn't the one doing it. So I'm not > too sure I remember the details correctly. By the sound of it, I've experienced similar issues with various flavors of driver and traced it back to multiple layers of overlapping transparency displayed withing Mozilla. https://bugs.freedesktop.org/show_bug.cgi?id=12671 may be relevant (and contains a simple test case from me). http://lists.freedesktop.org/archives/xorg/2008-March/033956.html is the thread I started on the issue. (Michal - I just noticed that that you responded to my update on that bug back in March. I'll try to have a run at getting that data this week, as well as testing the power of 2 idea.) -- Ross Vandegrift ross@xxxxxxxxxxx "The good Christian should beware of mathematicians, and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of Hell." --St. Augustine, De Genesi ad Litteram, Book II, xviii, 37 _______________________________________________ xorg mailing list xorg@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/xorg