[Pw_forum] compile MPI+OpenMP version

[Gabriele Sclauzero]

Il giorno 09/giu/2011, alle ore 03.44, Huiqun Zhou ha scritto:

> Paolo,
> 
> Yes, I had used that option. My question is that which library we should 
> choose, the multi-thread
> version, libmkl_intel_thread.a or the sequential version, 
> libmkl_sequential.a, of Intel MKL when
> compiling mixed MPI+OpenMP version of qe? Or, in other words, do we need to 
> take advantage
> of multi-threading functinality of Intel MKL when compiling MPI+OpenMP 
> version?

That's a good question, maybe it has already been asked, so you might gather some information on the archives. I don't know if anyone has a clear answer to it. It looks to me that the threaded MKL are not so efficient (i.e. you will probably not gain much by running more than one thread on a multicore cpu). If you could do some testing and share with us it would be nice. This might also depend a lot on the hardware that you have at hand and on the MKL version (maybe things have been improved in the meanwhile), so please specify both. You could do this test even in serial mode (without MPI compilation), it should already give some answers.

If you compile MPI+OpenMP, it means that you are going to do large scale calculations (i.e., lots of atoms, lots of cpus,...). Then, remember that's very important to link against ScaLapack libraries. 


Regards,

GS

> 
> Thanks!
> 
> zhou huiqun
> @earth sciences, nanjing university, china
> 
> 
> ----- Original Message ----- 
> From: "Paolo Giannozzi" <giannozz at democritos.it>
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Sent: Wednesday, June 08, 2011 9:55 PM
> Subject: Re: [Pw_forum] compile MPI+OpenMP version
> 
> 
>> 
>> On Jun 8, 2011, at 11:39 , Huiqun Zhou wrote:
>> 
>>> for MPI+OpenMP, should I use libmkl_intel_thread.a instead?
>> 
>> you should use "./configure --enable-openmp [other options]"
>> 
>> P.
>> ---
>> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>> 
>> 
>> 
>> 
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
>> 
> 
> 
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


§ Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20110609/e61460bc/attachment.html>