Phoronix published a review on the How To Make Counter-Strike: Global Offensive Run Much Faster On AMD Catalyst For Linux

A quote from the article:

Should you be using a Radeon graphics card with the AMD Catalyst Linux driver and are disappointed by the poor performance, there is a very easy workaround for gaining much better performance under Linux... In some cases a simple tweak will yield around 40% better performance!

Like Catalyst for Windows, Catalyst for Linux also makes use of application profiles for managing any per-game optimizations or workarounds for addressing driver bugs, etc. On Windows, AMD routinely even puts out hot-fix releases or special drivers that are "optimized" for major new AAA game releases. Most often these application profiles just result in the game/application running a few percent faster or to just workaround incorrect visuals. The concept of per-game/app profiles by graphics drivers is nothing new and is even similarly supported by the open-source Mesa drivers in rare cases when needing to workaround buggy software, override the exposure of certain OpenGL/GLSL capabilities, etc. Application profiles have been within the Catalyst Linux driver for years, but unlike Windows, these profiles aren't apparently maintained worth squat and is part of the reason why at least some Steam games struggle under Linux with Catalyst.

 How To Make Counter-Strike: Global Offensive Run Much Faster On AMD Catalyst For Linux @ Phoronix