VASP: Difference between revisions

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== Vasp-GPU ==
== Vasp-GPU ==
Vasp-GPU executable files run on both GPU and CPU of a node. Basically calculation on GPU of a node is much more expensive than CPU, therefore we highly recommend to perform a benchmark using one or 2 GPU to make sure they are using maximum GPU utilization. Fig.1 show a benchmark of Si crystal contains 256 Si-atoms in the unit-cell. 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 compare to GPU=0 and CPU=1. This clearly shows that beneficial of using GPU. However, a comparison between calculation with GPU=1 and GPU=2 indicates that there is not much performance gain from GPU=1 to GPU=2. In fact GPU utilization 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.
Vasp-GPU executable files run on both GPU and CPU of a node. Basically calculation on GPU of a node is much more expensive than CPU, therefore we highly recommend to perform a benchmark using one or 2 GPU to make sure they are using maximum GPU utilization. Fig.1 show a benchmark of Si crystal contains 256 Si-atoms in the unit-cell. 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 compare to GPU=0 and CPU=1. This clearly shows that beneficial of using GPU. However, a comparison between calculation with GPU=1 and GPU=2 indicates that there is not much performance gain from GPU=1 to GPU=2. In fact GPU utilization 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.
[[File:Vasp-benchmark.jpg|thumb|Fig.1 Simulation time as a function of number of CPU for GPU=0, 1, and 2]]


== Building VASP yourself == <!--T:12-->
== Building VASP yourself == <!--T:12-->
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