[gmx-users] low performance 2 GTX 980+ Intel CPU Core i7-5930K 3.5 GHz (2011-3)

[Carlos Navarro Retamal]

Dear Justin,
Thanks a lot for your reply.
I tried with another system (~130k with the same results) 1GPU > 2 GPU’s
In any case i’ll read the documentation you mention on your previous reply (and hopefully i’ll be able to run 2 process simultaneously .
Kind regards,
Carlos


--  
Carlos Navarro Retamal
Bioinformatic engineer
Ph.D(c) in Applied Science, Universidad de Talca, Chile
Center of Bioinformatics and Molecular Simulations (CBSM)
Universidad de Talca
2 Norte 685, Casilla 721, Talca - Chile   
Teléfono: 56-71-201 798,  
Fax: 56-71-201 561
Email: carlos.navarro87 at gmail.com or cnavarro at utalca.cl


On Tuesday, December 30, 2014 at 3:40 PM, Justin Lemkul wrote:

>  
>  
> On 12/30/14 1:38 PM, Carlos Navarro Retamal wrote:
> > Dear Justin,
> > Thanks a lot for your reply.
> >  
> > > You can use the multiple cards to run
> > > concurrent simulations on each (provided cooling is adequate to do this).
> > >  
> >  
> >  
> >  
> >  
> > I tried that. I launched 2 simulation at the same time, but on each i got the next warning at the end:
> >  
> > > Force evaluation time GPU/CPU: 3.177 ms/5.804 ms = 0.547
> > > For optimal performance this ratio should be close to 1!
> > >  
> > >  
> > > NOTE: The GPU has >25% less load than the CPU. This imbalance cause
> > > performance loss.
> > >  
> >  
> >  
> > and i got really low performance ( ~ 17ns/day each)
> > using the following commands:
> >  
> > > mdrun -deffnm test1 -gpu_id 0 -v
> > > mdrun -deffnm test2 -gpu_id 1 -v
> > >  
> >  
> >  
> >  
> >  
> > Is there a better way to perform multiple md simulations at the same time?
>  
> In this case, both GPU are probably fighting for CPU resources (note how the CPU  
> force evaluation is the limiting factor). You'll need to set -pin and  
> -pinoffset suitably, IIRC. See discussion at
>  
> http://www.gromacs.org/Documentation/Acceleration_and_parallelization
>  
> -Justin
>  
> --  
> ==================================================
>  
> Justin A. Lemkul, Ph.D.
> Ruth L. Kirschstein NRSA Postdoctoral Fellow
>  
> Department of Pharmaceutical Sciences
> School of Pharmacy
> Health Sciences Facility II, Room 629
> University of Maryland, Baltimore
> 20 Penn St.
> Baltimore, MD 21201
>  
> jalemkul at outerbanks.umaryland.edu (mailto:jalemkul at outerbanks.umaryland.edu) | (410) 706-7441
> http://mackerell.umaryland.edu/~jalemkul
>  
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