[gmx-users] Is it possible to control GPU utilizations when running two simulations in one workstation?

[sunyeping]

Dear all,

I am trying to run a two MD simulations on one workstation equipped with 4 GPU. First I started a simulation with the following command:

gmx mdrun -v -deffnm md -ntmpi 12 -gpu_id 0,1

By the nvidia-smi command I find the utilizations of GPU 0 and 1 are 74 and 80%, respectively. Then I started another simulation with:

 gmx mdrun -v -deffnm md -ntmpi 12 -gpu_id 2,3

then the utilizations of GPU 0 and 1 decreased to 20% and 23%, and the utilizations of GPU 2 and 3, which ran the second simulation, are 12 and 15%. Both of the two simulations ran with unbearable low speed.

I feel it very stange because a few days ago I also ran two simulations on the same workstation with the same mdrun commands, but the utilizations of all four GPU were higer than 70%. Do you know what may affect the GPU utilizations and how to correct it?

Best regards.