Last Updated on July 28, 2020
The LunarG Device Simulation layer helps test across a wide range of hardware capabilities without requiring a physical copy of every device. It can be applied without modifying any application binaries, and in a fully-automated fashion. The Device Simulation layer (aka DevSim) is a Vulkan layer that can override the values returned by your application’s queries of the GPU. DevSim uses a JSON text configuration file to make your application see a different driver/GPU than is actually in your system. This capability is useful to verify that your application both a) properly queries the limits from Vulkan, and b) obeys those limits.
The DevSim layer works for all Vulkan platforms (Linux, Windows, and Android). It is open-source software on GitHub, and the code strives to be clear and well-documented to serve as an example for writing Vulkan layers.
The role of DevSim is to “simulate” a less-capable Vulkan implementation by constraining the features and resources of a more-capable implementation. Note that the actual device in your machine should be more capable than that which you are simulating. DevSim does not add capabilities to your existing Vulkan implementation by “emulating” additional capabilities with software; e.g. DevSim cannot add geometry shader capability to an actual device that doesn’t already provide it. Also, DevSim does not “enforce” the features being simulated. For enforcement, you would continue to use the Validation Layers as usual, in conjunction with DevSim.