Translations:VASP/25/en

Vasp-GPU

Fig.1 Simulation time as a function of the number of CPUs for GPU=0, 1, and 2

Vasp-GPU executable files run on both GPUs and CPUs of a node. Basically, calculation on a GPU is much more expensive than on a CPU, therefore we highly recommend to perform a benchmark using one or 2 GPUs to make sure they are getting a maximum performance from the GPU use. Fig.1 shows a benchmark of Si crystal which contains 256 Si-atoms in the simulation box. Blue, black and red lines show simulation time as a function of Number of CPU for GPU=0, 1, and 2 respectively. It shows the performance for GPU=1,2 and CPU=1 is more than 5 times better compared to GPU=0 and CPU=1. However, a comparison of calculations with GPU=1 and GPU=2 indicates that there is not much performance gain from GPU=1 to GPU=2. In fact, use for GPU=2 is around 50% in our monitoring system. Therefore we recommend users to first perform a benchmark like this for their own system to make sure they are not wasting any computer resources.