Determining if GPU switching works?

I have a 8,3 MacBook Pro with an onboard Radeon 6700M GPU alongside the integrated Intel Sandy Bridge GPU. I recently upgraded to FGLRX 8.930/12.1, and Catalyst Control Center seemed to look the same, there weren't any different options as opposed to 8.920/11.12. However, [here](http://linux-hybrid-graphics.blogspot.com/2012/01/improved-support-for-amd-hybrid.html) it mentions that someone tested things out and was able to determine that with FGLRX on the same card as me, they were able to determine that GPU switching was, in fact, working. Unfortunately, the blog doesn't allow comments, so I can't ask this question there. Is there a way for me to determine if GPU switching is working or not between ATI and Intel cards? How can I know if it's working or not? Again, there doesn't seem to be anything in CCC that tells me whether it's enabled or not. There's "PowerPlay," but that seems to be more of a setting for battery-saving in general and doesn't make any mention of GPU switching. How can I test if GPU-switching/hybrid graphics is enabled and working on my Ubuntu 11.10 machine?