[gmx-developers] Hardware threads vs. OpenMP threads

[Mark Abraham]

Agreed.

Mark

On Thu, Jun 4, 2015 at 12:53 PM Berk Hess <hess at kth.se> wrote:

> PS There is something strange on that machine. If Gromacs detects 16
> threads, omp_get_num_procs should return 16, not 8.
>
> Berk
>
> On 2015-06-04 12:49, Berk Hess wrote:
> > Hi,
> >
> > I don't think anything changed in the master branch.
> >
> > But we do adhere to the OpenMP environment. The value reported in the
> > message comes from omp_get_num_procs, which should be a report about
> > the hardware available. OMP_NUM_THREADS sets the number of OpenMP
> > threads to use, that is respected.
> >
> > Cheers,
> >
> > Berk
> >
> > On 2015-06-04 11:21, David van der Spoel wrote:
> >> Hi,
> >>
> >> why does GROMACS in the master branch not adhere to the OpenMP
> >> environment?
> >>
> >> Number of hardware threads detected (16) does not match the number
> >> reported by OpenMP (8).
> >> Consider setting the launch configuration manually!
> >> Reading file md.tpr, VERSION 5.1-beta1-dev-20150603-99a1e1f-dirty
> >> (single precision)
> >> Changing nstlist from 10 to 40, rlist from 1.1 to 1.1
> >>
> >> Using 1 MPI process
> >> Using 16 OpenMP threads
> >>
> >> Cheers,
> >
>
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