this works like primusrun for nvidia? with bumblebee?
No, this is only power management (ie, turns off the discrete GPU when it's not in use). This does not actually perform the act of GPU offloading. For that you want one of the following:
1. When using fglrx (catalyst) you can use the common-amd branch of bumblebee. there are some tweaks to primus that will make it work (check the primus github)
2. When using radeon (xf86-video-ati) you can use PRIME offloading with Xorg 1.14
As I understand it the PXP power management as mentioned here is *only* for the open source drivers -- the official catalyst drivers have their own built-in power management. I am not sure when/where these options will be implemented, maybe someone else in this thread who knows a bit more can enlighten us.