[molpro-user] running parallel GA Molpro from under Torque?

[Grigory Shamov]

Hi Jeff,


On 13-11-27 2:22 PM, "Jeff Hammond" <jeff.science at gmail.com> wrote:

>> Thanks for the advice! We have no MVAPICH2, but there is Intel MPI which
>> is a derivative of it.
>
>MVAPICH and Intel MPI are derivatives of MPICH.  The IB code in Intel
>MPI is different than in MVAPICH.  As far as I know, Intel uses DAPL,
>which is ancient, whereas MVAPICH uses OFED (and PSM, if necessary).

Intel has both. What it doesn't have is Torque CPUset support.

>
>Building MVAPICH from source is not complicated and does not require
>admin rights.

I  do have admin rights. Actually, as an admin, I am reluctant to
proliferate kinds of MPI to support, and I think it would not be liked by
our other staff members. OpenMPI is our standard, we know how to use it
with our IB, and we rely on CPUsets, as we schedule by core, not by whole
node. 


>
>> The only way to use Intel MPI I know of is OSC mpiexec; this one does
>>not
>> allow oversubscription (i.e., no data-server processes) but would use
>> Torque   API to launch processes. Is there a(n easy) way to use OSC
>> mpiexec with the "molpro" script? Has anyone tried it so?
>
>Why do you want to oversubscribe?  I bet you that Molpro runs better
>if you don't.  Have you done a detailed performance evaluation of this
>already?

That is a good question. I haven't tried it yet. Perhaps I misread the
documentation: would  --multiple-helper-server oversubscribe, in terms of
Torque, as it would create additional data-server processes like
GAMESS-US, or would you just have some wasted cores with it? And it is
said that performance would be bad without them (perhaps due to the MPI
polling?). How bad is it?

>-- 
>Grigory Shamov
>
>HPC Analyst, Westgrid/Compute Canada
>E2-588 EITC Building, University of Manitoba
>(204) 474-9625
>
>