[gmx-users] GPU and MPI

[Da-Wei Li]

Hi, Albert

I think the error message is very clear. You have one MPI rank per node,
but provide 2 GPUs per node. The "gpuid" argument is applied on each of the
node.

dawei

On Mon, Sep 8, 2014 at 2:38 PM, Albert <mailmd2011 at gmail.com> wrote:

> Helo Yunlong:
>
> thx a lot for the reply.
>
> It works in Gromacs-4.6.5, but it does NOT in Gromacs-5.0.1. I used the
> following command:
>
> mpirun -np 2 mdrun_mpi -v -s npt2.tpr -c npt2.gro -x npt2.xtc -g npt2.log
> -gpu_id 01 -ntomp 10
>
>
> but it always failed with messages:
>
>
> 2 GPUs detected on host cudaB:
>   #0: NVIDIA GeForce GTX 780 Ti, compute cap.: 3.5, ECC:  no, stat:
> compatible
>   #1: NVIDIA GeForce GTX 780 Ti, compute cap.: 3.5, ECC:  no, stat:
> compatible
>
> 2 GPUs user-selected for this run.
> Mapping of GPUs to the 1 PP rank in this node: #0, #1
>
>
> -------------------------------------------------------
> Program mdrun_mpi, VERSION 5.0.1
> Source code file: /soft2/plumed-2.2/gromacs-5.0.1/src/gromacs/gmxlib/gmx_detect_hardware.c,
> line: 359
>
> Fatal error:
> Incorrect launch configuration: mismatching number of PP MPI processes and
> GPUs per node.
> mdrun_mpi was started with 1 PP MPI process per node, but you provided 2
> GPUs.
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors
>
>
>
> However, this command works fine in Gromacs-4.6.5, and I don't know why it
> failed in 5.0.1.
>
> best
>
> Albert
>
>
> On 09/08/2014 05:33 PM, Yunlong Liu wrote:
>
>> For using two GPU, just add option -gpu_id 01 to specify each gpu for
>> each MPI process.
>>
>>
>> Yunlong
>>
>
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