Phoronix: The Cost Of ATI Kernel Mode-Setting On Fedora 12

One of the articles on Phoronix last week was entitled Intel Linux Graphics Shine With Fedora 12, which showed off the nice state of Intel graphics on this latest Red Hat release when it came to kernel mode-setting and its 3D stack with it working well "out of the box" and offering some nice performance gains over the earlier Fedora 10 and Fedora 11 releases. While the Intel stack may be improved in Constantine, the ATI support has taken a hit, as users were quick to point out in response to last week's article. In particular, when using the ATI kernel mode-setting driver in Fedora 12 (which is the default for pre-R600 hardware), there is a large performance discrepancy compared to using the traditional user-space mode-setting for ATI Radeon hardware. Today we are looking at what exactly the performance cost is for using ATI KMS in this new release.