OpenGL mapping to GPU HW low-level details (and OpenCL)

OpenGL OpenGL: Advanced Coding
1

I’m looking for information (relevant posts, journal publications, developer guides, textbooks, open source reference implementations?..) which discuss HW details of various elements of the OpenGL programming model, such as

  1. shaders - how does the shader compile to machine-specific code, and how are shaders scheduled on the GPU (and is it different for a vertex vs fragment vs compute shader etc)?
  2. buffers/textures - how and where do OpenGL buffers, textures get placed in GPU memory and accessed from within shader code, how is the GPU memory hierarchy (registers, L1/L2/… caches, local, global device memory regions) utilized in these processes?
  3. HW fixed-function details - how is a tri-linear interp unit designed and operate? where are textures really placed in memory (and how/why is access faster for this than for “general” buffer memory… more parallel access banks, memory locality, different memory arch (SDRAM, DDR1/2/3/4, etc)) ?
  4. Also interested in how OpenGL implementation for shaders/compute-shaders differs from OpenCL compute kernels in terms of GPU HW utilization.

I realize a lot of these details for current HW is proprietary guarded IP, but even older “obsolete” HW which could give basic insight will be useful. Intel has the open-source Beignet and NEO driver projects which provide some of this information for OpenCL API. I haven’t looked at the Mesa project yet, but wonder how relevant that will be as SW-implementation.

I teach 2 EE Master’s classes at UW on GPU-Compute (OpenCL-based) and Scientific Visualization (OpenGL-based), and this information would be very useful for the curriculum and students.

VR,
Dr. Colin Reinhardt
University of Washington, Electrical and Computer Engineering Dept.

1 Like
2

Some of this information AMD have posted on their GPU Open site. (Not allowed to include links a search for GPU Open AMD should do you)

But as you also said, some of it is guarded IP or just contained inside the drivers system (like (1)) and will/can be different between vendors and even driver versions.

1 Like
3

This upcomming talk at GDC might also be of interest:
“GDC 2020 source to isa a trip down the shader compiler pipeline presented by amd 873405”