Fast GPU-in-the-loop simulation technique at OpenGL ES API level for Android Graphics Applications

Building a full system simulator for a CPU-GPU heterogeneous architecture recently draws keen attention of mobile device developers who want to run full software stacks without modification. A common practice is to integrate a GPU simulator with a CPU simulator, which runs very slow or is not applicable when the GPU simulator does not exist. To overcome these drawbacks, a HIL (Hardware-in-the Loop) simulation approach that integrates a real GPU with a CPU simulator has been proposed recently, in which HIL simulation is performed at the device driver level, supporting a specific GPU only. For design space exploration of CPU-GPU heterogeneous architecture, it is necessary to support various GPUs. To this end, we propose a GPU-HIL simulation technique that integrates a real GPU at the OpenGL ES API level, aiming to make a good compromise between speed and timing accuracy. Technical challenges and proposed solutions are presented in detail. Using three OpenGL ES Android benchmarks, preliminary experiments show some use cases of the proposed simulation framework for design space exploration and API-level dynamic behavior monitoring.