# Gromacs not utilizing gpu **URL:** \ **Category:** User discussions\ **Tags:** mdrun, gpu, qm-mm\ **Created:** [October 1, 2023, 9:55am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302 "2023-10-01T09:55:46Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![AKA](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@AKA](https://gromacs.bioexcel.eu/u/AKA)\ **Post date:** [October 1, 2023, 9:55am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/1 "2023-10-01T09:55:46Z")
GROMACS version: 2023.2 GROMACS modification: No I have compiled gromacs-cp2k with CUDA. The mdrun gpu utilization is zero always and I see occasional spike in gpu usage. ![Screenshot from 2023-10-01 15-16-35](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/5/571315cc3625972eb4bf66a767c33e8783d1d4da.png) ---
**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\ **Post date:** [October 2, 2023, 8:27am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/2 "2023-10-02T08:27:02Z")
In order to help you, we would need more information. Could you post the log file of a simulation, starting from the top of the file until the first simulation step? ---
**Author:** ![AKA](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@AKA](https://gromacs.bioexcel.eu/u/AKA)\ **Post date:** [October 3, 2023, 7:59am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/3 "2023-10-03T07:59:21Z")
Gromacs 2022.4 was built with cp2k for CUDA. The following are the commands used for the simulation. ```auto ############################classical###################### gmx_cp2k solvate -cp conf.gro -o conf.gro -p topol.top -shell 10 gmx_cp2k grompp -f em.mdp -p topol.top -c conf -o egfp-genions.tpr -maxwarn 10 gmx_cp2k genion -s egfp-genions.tpr -p topol.top -o conf.gro -neutral gmx_cp2k grompp -f em.mdp -p topol.top -c conf -o egfp-em.tpr gmx_cp2k mdrun -s egfp-em.tpr -deffnm egfp-em gmx_cp2k grompp -f md-mm-nvt.mdp -p topol.top -c conf.gro -t egfp-em.trr -o egfp-mm-nvt.tpr gmx_cp2k mdrun -s egfp-mm-nvt.tpr -deffnm egfp-mm-nvt -v gmx_cp2k make_ndx -f conf.gro > a 938-956 > name 18 QMatoms > q ###########################QMMM################################################ gmx_cp2k grompp -f md-qmmm-nvt.mdp -p topol.top -c conf.gro -t egfp-mm-nvt.trr -n index.ndx -o egfp-qmmm-nvt.tpr -maxwarn 1 gmx_cp2k mdrun -s egfp-qmmm-nvt.tpr -deffnm egfp-qmmm-nvt -v ############################################################################### ``` mdrun performs as expected in the MM part with max usage. The low performance is observed in the qmmm mdrun. ---
**Author:** ![MagnusL](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/magnusl/32/2380_2.png) [@MagnusL](https://gromacs.bioexcel.eu/u/MagnusL)\ **Post date:** [October 3, 2023, 9:58am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/4 "2023-10-03T09:58:05Z")
As I said, please provide the log file (until the first MD step) from the `gmx_cp2k mdrun -s egfp-qmmm-nvt.tpr -deffnm egfp-qmmm-nvt -v` that will provide more information. There is also another post on the forum that might be of interest to you: [GROMACS 2022+CP2K with GPU - #2 by dmorozov](https://gromacs.bioexcel.eu/t/gromacs-2022-cp2k-with-gpu/3897/2). Apparently not all GPUs are supported with CP2K. ---
**Author:** ![AKA](https://avatars.discourse-cdn.com/v4/letter/a/ba9def/32.png) [@AKA](https://gromacs.bioexcel.eu/u/AKA)\ **Post date:** [October 3, 2023, 10:21am UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/5 "2023-10-03T10:21:08Z")
Thank you very much. Please look at the log file: [egfp-em.log](https://gromacs.bioexcel.eu/uploads/short-url/tsi2ZxEMZWYfRo9xKrm0eyPjyxr.log) (354.7 KB) [egfp-mm-nvt.log](https://gromacs.bioexcel.eu/uploads/short-url/paD8g0Rxx9laohxqkTn1D1Fnfnp.log) (27.4 KB) [egfp-qmmm-nvt.log](https://gromacs.bioexcel.eu/uploads/short-url/lGKJ0MsWTtD6IVHq4bc97nlkQ3r.log) (18.0 KB) ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [October 3, 2023, 3:15pm UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/6 "2023-10-03T15:15:51Z")
This question is also being answered here: [Mdrun : An error occurred in MPI\_Allreduce](https://gromacs.bioexcel.eu/t/mdrun-an-error-occurred-in-mpi-allreduce/7307) I think we should continue there. ---
**Author:** ![organicchemistry\_01](https://avatars.discourse-cdn.com/v4/letter/o/6bbea6/32.png) [@organicchemistry\_01](https://gromacs.bioexcel.eu/u/organicchemistry_01)\ **Post date:** [January 20, 2024, 1:04pm UTC](https://gromacs.bioexcel.eu/t/gromacs-not-utilizing-gpu/7302/7 "2024-01-20T13:04:30Z")
The QMMM in CP2K is not yet implemented in GPU, there was a plan, but not sure were it is now. So, when calculation hits the QMMM, you are being bottlenecked by CP2K cpu calculations. See here for the status of QMMM GPU implementation: [https://www.cp2k.org/gpu](https://www.cp2k.org/gpu)