Force Update on GPU

User discussions
1

GROMACS version: 2020.6
GROMACS modification: Yes/No

I am testing Gromacs on 4 GPUs/node. For 100K particle system with a single node, I am getting around ~50% performance boost with -update gpu. I am really excited about the number, but worried about the following warning,

““This run will default to ‘-update gpu’ as requested by the GMX_FORCE_UPDATE_DEFAULT_GPU environment variable. GPU update with domain decomposition lacks substantial testing and should be used with caution.””

I wondering, what type of caution should I take before jumping into using -update gpu ???. If there are any know issues or so?

Runtime settings

export GMX_GPU_DD_COMMS=true
export GMX_GPU_PME_PP_COMMS=true
export GMX_FORCE_UPDATE_DEFAULT_GPU=true

gmx mdrun  \
    -ntmpi 8 -ntomp 8 \
    -pin on  \
    -nb gpu \
    -bonded gpu \ 
    -pme gpu  \
    -npme 1 \
    -deffnm final

Thanks in advance fro your help.

Regards,
Masrul