From: Chitrak Gupta (chgupta_at_mix.wvu.edu)
Date: Thu Jul 20 2017 - 11:09:29 CDT
Hi Giacomo,
Thanks for the response.. No, I don't need to use the SMP version, just MPI
is fine for me. I had originally tried it like this
env MPICXX=mpicxx ./build charm++ mpi-linux-x86_64 --with-production
That worked but the scaling was extremely poor. That's when I felt maybe
using iccstatic would be better. Do you have any inputs for this?
Chitrak.
On Wed, Jul 19, 2017 at 9:14 PM, Giacomo Fiorin <giacomo.fiorin_at_gmail.com>
wrote:
> Hi Chitrak, I would specify manually only one of the compilers, or neither
> one if possible. The architecture mpi-linux-x86_64 should already take
> care of calling mpicxx, and you should load the relevant environment module
> set the MPI library and wrapper to the Intel version.
>
> Also, check this from the NAMD release notes:
>
> *MPI-based SMP builds have worse performance than verbs or ibverbs and are
> not recommended, particularly for GPU-accelerated builds.*
>
> So, stick to plain MPI if you must use SMP (for example because you want
> to communicate more efficiently with the GPU), or otherwise skip MPI use
> the IBverbs option for Charm++.
>
> Giacomo
>
> On Wed, Jul 19, 2017 at 6:47 PM, Chitrak Gupta <chgupta_at_mix.wvu.edu>
> wrote:
>
>> Hi NAMD users
>>
>> I am trying to compile the latest nightly build version of NAMD on
>> Stampede 2. For building charm 6.8 beta2 I used the following command that
>> was recommended by the interactive session
>>
>> ./build charm++ mpi-linux-x86_64 iccstatic mpicxx smp -j16
>> --with-production
>>
>>
>> However, I am getting the following error:
>>
>> Error> Tried to specify two compilers: iccstatic and mpicxx
>>
>>
>>
>> How should I fix this?
>>
>>
>> Best regards,
>> Chitrak.
>>
>
>
>
> --
> Giacomo Fiorin
> Associate Professor of Research, Temple University, Philadelphia, PA
> Contractor, National Institutes of Health, Bethesda, MD
> http://goo.gl/Q3TBQU
> https://github.com/giacomofiorin
>
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