Announcement

Collapse
No announcement yet.

RadeonSI's New SDMA Texture Copy Code Lands In Mesa

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • RadeonSI's New SDMA Texture Copy Code Lands In Mesa

    Phoronix: RadeonSI's New SDMA Texture Copy Code Lands In Mesa

    There is more exciting open-source AMD work to share today, a week before the feature freeze for the next version of Mesa...

    Phoronix, Linux Hardware Reviews, Linux hardware benchmarks, Linux server benchmarks, Linux benchmarking, Desktop Linux, Linux performance, Open Source graphics, Linux How To, Ubuntu benchmarks, Ubuntu hardware, Phoronix Test Suite

  • #2
    Progress progress progress

    Comment


    • #3
      One of the biggest issues of AMD drivers (both open and closed source) is texturing performance. Improvements here are very much needed.

      Comment


      • #4
        Originally posted by phoronix View Post
        SDMA in this context is short for System DMA (Direct Memory Access) and is a new asynchronous DMA engine originally added to Radeon GPUs with GCN 1.1 Sea Islands.
        It is not a "new engine" (btw. there are 2 per GPU), when it has been in products that hit the market 3 years ago, imho.

        I wonder if they even use this feature for OGL and D3D<12 in their Windows drivers. It is a feature hyped a bit when talking about Vulkan and D3D12 with their multiple queues (copy, compute, gfx queues) that could be worked on in parallel (buzzword "asynchronous compute").
        I thought this was only usable with the new APIs and explicit usage with thise distinct queues...

        Comment


        • #5
          SDMA has been used in the Windows drivers for a long time, but just for things like buffer upload/downloads when the OS / memory manager decides a buffer should be somewhere else (often because the memory that buffer occupies is needed for another buffer).

          With the new APIs they can start to be used directly by the applications / game engines, and "best guess" moves by OS / memory manager can be replaced with "optimized for this app" moves by the application.
          Test signature

          Comment


          • #6
            Originally posted by phoronix View Post
            [...], a week before the feature freeze for the next version of Mesa...
            The intended freeze date is either 20th or Intel gen8+ getting 4.2, whatever is later.

            Comment


            • #7
              Is this even used for iGPUs? I would have imagined, since there you can map memory as you wish, it wouldn't be necessary, right?

              Comment


              • #8
                Originally posted by CrystalGamma View Post
                Is this even used for iGPUs? I would have imagined, since there you can map memory as you wish, it wouldn't be necessary, right?
                As stated in the text, it is. However, it may cause degradation as the DMAs don't support delta color compression, therefore have more data to transfer which is significant when using an APU with low system memory bandwidth.

                Originally posted by atomsymbol
                With current Mesa 11.3.0-git drivers, the performance of for example Tomb Raider doesn't depend on the "Texture quality" in-game setting.
                It is unusual that the texture settings have a bigger impact on performance, as long as the VRAM is sufficient.
                However, I imagine this may help open world games that heavily rely on streaming and reduce streaming hiccups there...

                Comment

                Working...
                X