It's been a while since last looking on the anti-aliasing performance of the R600 Gallium3D driver so for this article we have some fresh MSAA benchmarks of the driver from Mesa 10.1-devel and using a Cayman-based high-end AMD Radeon graphics card.
The purpose of this testing is to just provide some new benchmarks of what users of the open-source Radeon Gallium3D driver can expect when enabling Multi-Sample Anti-Aliasing. MSAA can be enabled either via from the game/application itself or for easy testing purposes can be controlled on recent Mesa releases from the GALLIUM_MSAA environment variable or the functionally-identical __GL_FSAA_MODE environment variable.
In general the Mesa support for MSAA -- and anti-aliasing in general -- has lagged behind the closed-source drivers. The binary AMD / NVIDIA drivers support more forms of anti-aliasing and generally with better performance. The R600 Gallium3D driver just supports two, four, and six samples for MSAA right now. The other anti-aliasing alternative inside of Mesa is Morphological Anti-Aliasing.
The R600g MSAA benchmarks were done from an AMD A10-6800K APU setup with a Radeon HD 6950 graphics card. On the software side was Ubuntu 13.10 x86_64 with the Linux 3.13 Git kernel and a recent Mesa 10.1-devel Git snapshot from the Oibaf PPA. All OpenGL MSAA benchmarking on the open-source AMD Linux driver was done -- as always -- via the Phoronix Test Suite software.