Slashdot Mirror

← Back to Stories (view on slashdot.org)

AMD Catalyst Linux Driver Performs Wildly Different Based On Program's Name

Posted by Soulskill on from the a-rose-by-any-other-name-would-still-render-as-fast dept.

An anonymous reader writes: In past years the AMD Catalyst Linux driver has yielded better performance if naming the executable "doom3.x86" or "compiz" (among other choices), but these days this application profile concept is made more absurd with more games coming to Linux but AMD not maintaining well their Linux application profile database. The latest example is by getting ~40% better performance by renaming Counter-Strike: Global Offensive on Linux. If renaming the "csgo_linux" binary to "hl2_linux" for Half-Life 2 within Steam, the frame-rates suddenly increase across the board, this is with the latest Catalyst 15.7 Linux driver while CS:GO has been on Linux for nearly one year. Should driver developers re-evaluate their optimization practices for Linux?

5 of 114 comments (clear)

  1. Speed v.s. reliability by Z00L00K · · Score: 5, Interesting

    Speed increases may be sacrificing some reliability or cutting some corners. In a FPS game it may be worth it to reduce number of bits in the graphics to increase the frame rate in fast moving images but if you work on photo editing then you want precision rather than speed.

    Maybe looking at the name of the executable was an easy way around that.

    --
    If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
    1. Re:Speed v.s. reliability by jrumney · · Score: 5, Interesting

      So they have a whitelist to deal with this problem rather than an API call. The cynic in me wonders how much AMD charges to have your game listed on that whitelist.

    2. Re:Speed v.s. reliability by ckatko · · Score: 4, Interesting

      You mean like how in nVidia's control panel (and surely AMD has one) I already have per-application graphics settings for things like anti-aliasing, and negative LOD bias? Surely, if this was "laziness" they could have just used that existing infrastructure?

    3. Re:Speed v.s. reliability by Kjella · · Score: 4, Interesting

      Most of the time the information would be roughly as useful as a C compiler telling you what loops it will unroll. Game-specific optimizations basically means "take the whole rendering pipeline, make optimized shaders like ASM, reorder, parallelize, cut excess calculations, use conditional simplified algorithms and whatnot to achieve essentially the same output". It's not surprising that most of these tricks will work on a game built by the same engine, but it doesn't extend to the general case. So it wouldn't really be very useful, instead of "photo" or "fps" the profiles would basically be one per game.

      I remember at some point the AMD open source developers said that they didn't have manpower to optimize for different workloads, so they were going with a simple structure using only one algorithm. They guesstimated that they could typically get 70% performance, simply because past a certain point making some things run better would make other things run worse. At the time they were more busy making it work at all though, but it might have been based on experience from Catalyst. Remember there's a pretty big gap between DirectX/OpenGL and actual hardware, at least before DX12/Vulkan/Mantle.

      --
      Live today, because you never know what tomorrow brings
  2. Re:However... by Anonymous Coward · · Score: 4, Interesting

    I didn't notice any visible difference, or rendering errors.

    Then again, our renderer is pretty ancient technology by many standards, although in some aspects at par with Doom3 / Source engine. All of these are based on the same-ish code (Quake1) originally and in many aspects OpenGL stuff is very similiar in all three, so I'm not surprised that optimizations carry over. I would expect Xonotic to get some boost too :)