AMD Kaveri: Gallium3D vs. Catalyst Drivers
Now having looked at the Windows 8.1 vs. Ubuntu Linux performance, carried out an initial GPU comparison, and compared several Intel/AMD processors, our latest performance investigation with AMD's A10-7850K "Kaveri" APU is looking at the Radeon R7 Graphics performance on Ubuntu Linux when using the open-source "RadeonSI" Gallium3D driver and then using the closed-source AMD Catalyst driver.
All the published AMD Kaveri Linux benchmarks up to this point have been with the AMD Catalyst Linux graphics driver. As outlined in my original AMD Kaveri Linux article, the open-source Linux GPU driver support for this GCN-based APU isn't quite baked at this point.
Out of the box on Ubuntu 13.10 the A10-7850K had kernel mode-setting but no 2D/3D hardware acceleration nor even a proper X.Org DDX driver. When I tried out the Git code from Mesa in preparation for my launch-day Kaveri article, it produced a segmentation fault and wasn't in good standing. However, after trying out the driver packages from the Oibaf PPA, the situation was better.
With the Oibaf Personal Package Archive providing the Mesa packages built specifically for Ubuntu 13.10, the AMD Kaveri APU seemed happy. There was OpenGL (3D) acceleration and 2D acceleration working via GLAMOR: see some early GLAMOR 2D vs. Catalyst benchmarks. My initial Oibaf driver package testing for this article was done on Linux 3.12 but when running some benchmarks the display would no longer receive a signal. When upgrading to the Linux 3.13 kernel, these display issues went away and it was stable for all of the benchmarking.
Long story short, it was possible to get the A10-7850K working with the open-source RadeonSI Gallium3D driver when using the Linux 3.13 Git kernel paired with the updated X.Org/Mesa packages from the Oibaf PPA on Ubuntu 13.10.
To see how the current open-source Kaveri graphics performance is from Ubuntu, I compared its Linux 3.13 + Mesa 10.1-devel OpenGL performance against the same system but when using the Catalyst driver (fglrx 13.30.1; and having to down-grad to the Linux 3.12 kernel due to the binary driver's kernel compatibility issue). For this preview of the open-source vs. closed-source GPU driver performance of Kaveri was a range of Linux games and tech demos run via the Phoronix Test Suite. Swap buffers wait was disabled, as always, for the xf86-video-ati DDX during the benchmarking process.