The Big RadeonSI Performance Patch To Land In Linux 3.13
The patch for the Radeon HD 7000 series graphics processors and newer sharply improves the OpenGL performance for some workloads. The open-source AMD Linux driver finally correctly sets up the render back-ends for the hardware. It turns out the open-source driver was only enabling the render back-end on the first shader engine for modern Radeon GPUs rather than eabling all the render back-ends.
With this simple fix, the performance improved sharply for some workloads. The RadeonSI performance went up by 6x for Marek with the Unigine Sanctuary benchmark as an example.
At the time the patch was published we didn't know if it would go into the current Linux 3.13 kernel or be held off until the Linux 3.14 merge window, but it's just been called for landing in 3.13. This performance boosting patch is technically a fix and Red Hat's David Airlie went ahead today to send in a batch of Radeon DRM fixes for Linux 3.13.
There's a handful of open-source AMD Radeon kernel driver patches and among them is a fix for a UVD check, Sea Islands / Hawaii fixes, and some other minor work. Assuming Linus is okay with the pull request, it will be part of Linux 3.13-rc7 when released this forthcoming weekend. The stable release of Linux 3.13 is expected mid-January. New RadeonSI benchmarks will come on the Linux 3.13 kernel when I'm back from Russia.