This is a little bit mind-bending, but I've found the problem, at least on my precise desktop using Intel Sandy Bridge graphics...
1. I disable all the fancy new opengl rendering options so compiz should use regional redraws, so useFbo is always false. 2. On startup, I get a couple of frames with (mask & COMPOSITE_SCREEN_DAMAGE_ALL_MASK) so doubleBuffer.render is called with fullscreen==true. This calls: GLXDoubleBuffer::swap() --> copyFrontToBack() because useFbo was false --> glCopyPixels(). 3. After startup, all frames use GLXDoubleBuffer::blit() --> GL::copySubBuffer(), which is now slow. To make rendering fast again, all I have to do is break the sequence in #2. Either: (a) Force fullscreen=false; or (b) Comment out copyFrontToBack(); or (c) Comment out glCopyPixels() So the problem, on my desktop where I've done all my performance comparisons, is that calling glCopyPixels just once or twice on startup will forever make GL::copySubBuffer take a slow rendering path thereafter. If I ensure glCopyPixels is never touched on startup then Mesa stays in fast mode for GL::copySubBuffer. -- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/1037411 Title: [regression][GLES] Benchmark results are 15-40% lower with the gles2 code (compiz 0.9.8.0) To manage notifications about this bug go to: https://bugs.launchpad.net/compiz/+bug/1037411/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : [email protected] Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp
