stress_weston is an open source project designed to create very specific GPU workloads using OpenGL on top of the Weston compositor. These workloads can be used to test the performance of systems. Due to the very specific nature of the workloads it can generate, it is very useful for testing GPU preemption capabilities as outlined in the ACRN hypervisor project. See more information about GPU preemption at https://projectacrn.github.io/
There preemption details are in Developer Guides -> High-Level Design Guides -> Emulated Devices -> GVT-g GPU Virtualization
This app consists of 4 highly configurable test scenes/workloads useful for evaluating pre-emption performance and inducing specific kinds of workloads to test the performace of a system.
A makefile is provided with the distribution. It should work on most Yocto or Clear linux installations. The sample compiles against:
- Weston compositor
- Weston IAS package
- GLM - OpenGL Math Library v0.9.8.4 Make sure you have those packages or bundles installed. GLM is a source-only component and therefore must be located in an appropriately named directory (./glm) in your source folder.
The following steps will build stress-weston on Clear Linux:
$ sudo swupd bundle-add os-clr-on-clr software-defined-cockpit-dev devpkg-glm
$ wget https://cdn.download.clearlinux.org/releases/current/clear/x86_64/os/Packages/glm-dev-0.9.9.2-3.x86_64.rpm
$ git clone https://github.com/intel/stress-weston
$ cd stress-weston
$ make
Optional manual installation of glm:
$ sudo rpm -i glm-dev-0.9.9.2-3.x86_64.rpm --force --nodeps
By default, if you provide no command line parameters, stress_weston will read the params.txt file in the local directory.
If you give a filename after the executable like this:
stress_weston myparams.txt
It will read and use the 'myparams.txt' file for settings. This is handy for keeping and switching between parameters files quickly.
The parameters file controls the startup parameters of the tests. You MUST follow the format specified in the params.txt sample file. Don't re-arrange parameters or delete/add any lines. Each parameter needs to be on its own line and anything past the // comment marker is ignored.
Format of params line: Line # value // comment
Parameters File Format:
- Window width (in pixels)
- Window height (in pixels)
- Fullscreen mode (0=fullscreen, 1 = windowed mode)
- Save per frame metrics into a comma seperated value file. The CVS filename is automatically generated with the current date/time stamp. It contains the frame time for every frame seperated by comma. This is useful for automated testing or making sure there are no single frame spikes.
- Draw to an offscreen buffer (0=onscreen, 1=offscreen). If you render offscreen, then nothing will appear on the screen.
- Vsync on/off (0=vsync off, 1=vsync on)
- eglSwapbuffers (0=do not call eglSwapBuffers, 1=normal rendering). If the app is directed not to call eglSwapbuffers, then no onscreen updates will happen.
- Test scene to render. There are 5 different 'scenes' that have specific workloads. Set this paramter to a value between 0 and 5.
0 = Dual dials scene. 2 spinning dials are rendered. Dummy per-pixel work might be performed by the pixel shader if indicated by parameter 16. The number in parameter 16 specifies how many per-pixel loops with dummy math are performed. Paramter 16 is 0, then the dial faces will be completely black to indicate there is no extra per-pixel work being done. If there is some per-pixel work, then the dial faces will have a light red tint to indicate per-pixel work is being done.
General comments about scenes 1,2, and 5: In this mode, a 3D volume of pyramids are drawn in a grid. The number of pyramids in the grid is controlled by the paramters 11, 12, and 13 (X, Y, and Z direction respectively). The rendering of the pyramids always proceeds from furthest back (z-axis) to the front so the maximum amount of rendering must take place (this avoids early-Z test rejection). It is good practice to keep the grid roughly box-shaped so that when adding more pyramids, they occupy roughly the same amount of screen space as opposed to a grid that stretches in only one or two directions. This helps the work scale more predictably if you add/remove pyramids. Each pyramid consists of 6 triangles.
The pixel shader used for rendering these pyramids also has an option to add some dummy, per-pixel math operations to add load. Parameter 15 controls the amount of extra per-pixel work done by the pixel shader when rendering each triangle of a pyramid. If parameter 15 is set to 0, then the pyramids are drawn in pure per-vertex colors of red, green, blue. If parameter 15 is non-zero, then the pyramids will have a slight blue tint to indicate extra per-pixel work is being done.
1 = Single Buffer Draw The triangles for all the pyramids are created in a single vertex buffer and drawn in a single GL render command. This is useful for making sure a single draw command can be interrupted.
2 = Multiple Draw A single vertex buffer is created that has only 1 pyramid in it. Each pyramid is drawn via a seperate gl render command after modifying the render location in the constant buffer.
5 = Group Draw The triangles for all the pyramids are created into N vertex buffers and each rendered with a individual GL render call. Parameter 14 controls how many seperate vertex buffers/draw calls the pyramids should be broken into.
For example, if paramters 11,12,13 are 6,6, and 6 - this means 216 pyramids will be drawn. If parameter 14 is set to 8, this means that 8 vertex buffers with 27 pyramids each will be created. The GL render command will be issued 8 times total, 1 for each of the vertex buffers. If parameter 14 is set to 1, it is the same as rendering the Single Buffer Draw scene. If it's set to the number of pyramids specified by parameters 11,12, and 13, then it is identical to scene 2 - muliple draw.
3 = Full-screen quad with texture (and optional blur filter) In this mode, a single full-screen quad (2 triangles that cover the entire screen) is drawn. A texture is applied to the quad, unless parameter 9 is set to 1. If parameter 9 is set to 1, then no texture is drawn and the quad is simply drawn with a flat grey shader.
Parameter 10 controls the faux-blur shader. The faux-blur pixel shader simply does a number of texture fetches of neighboring pixels and averages them to create a simple blur effect. The number of pixels it fetches in the X and Y directions from the center pixel is controlled by parameter 10. Ex: if parameter 10 is set to 0, then no surrounding pixels are sampled and no blur effect is applied. If the parameter is set to 4, then 4 pixels in the X and Y direction will be sampled, per-pixel, by the pixel shader. This test is very useful for testing common post-processing workloads that do many texture fetches/samples.
4 = Long, compute-intensive shader In this mode, a single, full-screen quad is drawn with a rotating texture. Some simple shader math operations are done per-pixel in a loop. The number of math operations per pixel is controlled by parameter 17. This scene is very useful for testing heavy compute shaders.
18 - the number of frames stress-weston should render before exiting. Setting this value to 0 indicates it should run forever.
If you have a keyboard plugged into your system, you can press these keys:
'c' - change to the next test in the suite
<esc> - exit the tests
On the pyramid scene tests:
'+' - add 5 more pyramids to each direction (x/y/z) of the grid being drawn
'-' - subtract 5 pyramids in each direction (x/y/z) of the grid being drawn
On the longshader test:
'+' - add 500 loops to each pixel shader invocation
'-' - subtract 500 loops from each pixel shader invocation
It is easy to run more than one instance of the workload tests as there are no dependencies. My recommendation is to dump the output to null if you have more than one going:
stress_weston > /dev/null &
Weston does not give permission for an app to move itself. You need to use the surfctrl app to move the app to different screens/locations. surfctrl --surfid=XXXXXXX --pos=1920x0 is a handy command to move something to a second monitor (if the first monitor is running 1920x1080)