[gmx-users] multiple GPU usage for simulation

[pbuscemi at q.com]

I am not expert on this subject but have recently gone through the
exercise...

Firstly, does nvidia-smi indicate both cards are active ?

Secondly,  for the nvt or npt runs  have you tried mdrun commands similar to
: 

mdrun -deffnm  file  -nb gpu  -gpu_id 01
or
mdrun -deffnm  file  -nb gpu -pme  gpu -ntomp 5 -ntmpi 10 -npme 1 -gputasks
111110000
or
mdrun -deffnm  file  -nb gpu -pme  gpu -ntomp 5 -ntmpi 10 -npme 1 -gpu_id 01

this may help select both 

hope it helps
Paul

-----Original Message-----
From: gromacs.org_gmx-users-bounces at maillist.sys.kth.se
<gromacs.org_gmx-users-bounces at maillist.sys.kth.se> On Behalf Of praveen
kumar
Sent: Tuesday, January 29, 2019 10:59 AM
To: gromacs.org_gmx-users at maillist.sys.kth.se
Subject: [gmx-users] multiple GPU usage for simulation

Dear gromacs users

I am working on molecular simulation using gromacs 2018.4, we have a new gpu
machine which has two GPU cards.

I have new workstation  with 20 cores  (Intel I9 processors) with 3.3 GHz

Nvidia Getforce X1080 Ti cards(2 nos)

I have tried running simulation using the command  gmx mdrun -v -deffnm test

getting this message

Using 1 MPI process
Using 10 OpenMP threads

1 GPU auto-selected for this run.
Mapping of GPU IDs to the 2 GPU tasks in the 1 rank on this nodes:

It seems simulation runs by make use of one GPU instead of two. I have
checked it using nvidia-smi.

similar error has got already in the given link
https://mailman-1.sys.kth.se/pipermail/gromacs.org_gmx-
users/2018-April/119915.html

I have tried all those options given by Mark and other people, I am
wondering whether this issue cab be solved ? I.e. Make use of two gpu cards
for one simulation run

I would be really thankful to if anyone can help me in this regard.

Thanks
Praveen


--
Thanks & Regards
Dr. Praveen Kumar Sappidi,
National Post Doctoral Fellow.
Computational Nanoscience Laboratory,
Chemical Engineering Department,
IIT Kanpur, India-208016



-- 
Thanks & Regards
Praveen Kumar Sappidi,
National Post Doctoral Fellow.
Computational Nanoscience Laboratory,
Chemical Engineering Department,
IIT Kanpur, India-208016
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