MSAA RadeonSI Gallium3D Performance Preview

For those curious about the performance overhead of enabling multi-sample anti-aliasing (MSAA) with the RadeonSI Gallium3D driver, here are a few benchmarks showing the performance overhead at various MSAA levels with the latest open-source AMD Linux driver.

Like with the R600 Gallium3D driver, exposing MSAA via the RadeonSI Gallium3D driver can simply be done by setting the GALLIUM_MSAA environment variable with a value (currently up to 6), regardless of whether the application/game exposes an MSAA setting. Unfortunately, none of the other advanced anti-aliasing modes or settings offered by the Catalyst driver are currently available with the open-source driver.

Additionally, the RadeonSI MSAA doesn't work everywhere... In my tests, when using the RadeonSI MSAA the screen became totally corrupted when running any Source Engine game like Counter-Strike: Source and Team Fortress 2.

This testing was done with a Radeon R9 270X graphics card running Ubuntu 14.10 but with upgrades to the Linux 3.17 Git kernel. Mesa 10.2.6 and xf86-video-ati 7.4.0 was the user-space Radeon graphics components currently provided by Ubuntu 14.10 Utopic Unicorn. All benchmarks were handled by the Phoronix Test Suite.