RadeonSI Gallium3D Is Improving, But Still Long Shot From Catalyst

While NVIDIA's binary driver is much faster and better than AMD's Catalyst, on the open-source driver side is where AMD has been shining. While their RadeonSI Gallium3D driver for Radeon HD 7000 series GPUs and newer is not nearly as well off as their pre-HD 7000 series (R600g) Gallium3D driver, they are making progress. In this article are benchmarks showing the "out of the box" performance on Ubuntu 13.10 with the modern open-source driver, benchmarks with the latest kernel and Mesa and LLVM, and then the AMD Catalyst driver. A range of modern Radeon HD 7000 and R9 graphics processors were used for this open-source versus closed-source driver testing.

A few days ago I shared some new RadeonSI benchmarks showing major improvements with the Linux 3.13 kernel thanks to Radeon Dynamic Power Management being enabled by default and the kernel having an important performance fix. Aside from the Radeon DRM kernel driver improvements there's been a lot of activity in recent months on the RadeonSI Gallium3D driver and with that there's improvements to the AMD GPU LLVM compiler back-end that is now in good shape with LLVM 3.4.

While the open-source driver is constantly being improved for the Radeon HD 7000/8000 and Rx 200 series graphics processors, the Catalyst driver is still much faster, feature complete, and has better OpenGL support. With the Mesa 10.1-devel stack used in this round of testing there's still only OpenGL 3.1 support where as Catalyst ships OpenGL 4.2 support for the modern GPUs. You can read dozens of other Phoronix articles about missing or incomplete features of the open-source Radeon driver.

In this article benchmarks were done from Radeon HD 7850, Radeon HD 7950, and R9 270X graphics cards. The comparison was limited due to hardware I had available and works on the current RadeonSI stack (the Radeon R9 290 is still in poor shape with the latest code). The software configurations used for testing included:

- The "out of the box" open-source AMD Linux driver in Ubuntu 13.10. This includes the Linux 3.11 kernel, xf86-video-ati 7.2.0, Mesa 9.2.1, and LLVM 3.3. This driver configuration for RadeonSI hardware only yields OpenGL 2.1 support.

- Ubuntu 13.10 with upgrading to Mesa 10.1-devel and other latest open-source packages via the Oibaf PPA.

- The Ubuntu 13.10 upgraded stack against the Oibaf PPA and then moving from the Linux 3.11 kernel to Linux 3.13 Git.

- Lastly was Ubuntu 13.10 running with the AMD Catalyst binary graphics driver (fglrx 13.10.10 / OpenGL 4.2.12337).

Similar tests were also done with the mature "R600g" Gallium3D driver and compared to Catalyst. Those older Radeon GPU results will be published on Phoronix in the days ahead. Swap buffers wait was disabled for the xf86-video-ati DDX during all of the benchmarking.

If you appreciate all of this frequent Linux graphics card and driver testing done exclusively at Phoronix, please consider subscribing to Phoronix Premium or making a PayPal tip. Premium subscribers are able to read entire articles (such as this one) on a single page and view the site without advertisements. If not a subscriber, at the very least please do not use AdBlock when reading Phoronix.com as it deprives much-needed revenue from the site that is expensive and very time consuming to operate; frequently I am still working 80+ hour weeks on Phoronix. Special thanks for making this article possible include the Cisco welcome screen ad campaign running for US readers the next few days on Phoronix and also to Phoronix reader Aaron Watry for sponsoring this round of AMD Radeon Linux testing.

The three AMD Radeon GCN graphics cards with the four tested software/driver configurations were all done from an Intel Core i7 4770K "Haswell" system. All benchmarking was handled via the Phoronix Test Suite.