How to use glmark2-drm on a Raspberry Pi to test an external GPU

 Run on a Raspberry Pi with an external graphics card glmark2 (an OpenGL 2.0 and ES 2.0 benchmark tool).

glmark2 isn't available in any Pi repositories, so you have to build it from source:

sudo apt install -y meson libjpeg-dev libdrm-dev libgbm-dev libudev-dev
git clone https://github.com/glmark2/glmark2.git
cd glmark2
meson setup build -Dflavors=drm-gl,drm-glesv2
ninja -C build
sudo ninja -C build install

Only for drm, so it can run fullscreen without requiring an X/Wayland environment. To use the whole suite, follow these steps:

glmark2-drm

You may use glmark2-drm -b jellyfish to perform a specific benchmark.

pi@radeon10:~ $ glmark2-drm -b buffer
=======================================================
    glmark2 2021.12
=======================================================
    OpenGL Information
    GL_VENDOR:      X.Org
    GL_RENDERER:    AMD CEDAR (DRM 2.50.0 / 5.10.17-v8+, LLVM 11.0.1)
    GL_VERSION:     3.1 Mesa 20.3.5
    Surface Config: buf=32 r=8 g=8 b=8 a=8 depth=24 stencil=0
    Surface Size:   1920x1080 fullscreen
=======================================================
[buffer] <default>: FPS: 29 FrameTime: 34.483 ms
=======================================================
                                  glmark2 Score: 29 
=======================================================

It's not the finest performing configuration in the world on a Raspberry Pi 4 with an AMD Radeon 5450—half the tests aren't running yet—but it's a useful tool to evaluate whether you still need to enhance the drivers:)