[CP2K-user] [CP2K:12239] Running Cp2k in parallel using thread in a PC

[Pierre Cazade]

Hi Nikhil,

This is an excellent question. I did not try the GPU version of CP2K 
yet. I am actually trying to compile it on the cluster that I am using.

Normally, you only need to install CUDA libraries and set up the 
environment variables properly. Then, the executable detects the 
presence of the GPU automatically, provided you have installed the 
driver from nvidia. At least, this is how gromacs behaves, for example. 
Which linux distribution are you using?

If you use the GPU, avoid using too many threads. Ideally, one per GPU.

Regards,
Pierre

PS: Regarding your previous post: rather than "mpirun -n 2", try "mpirun 
-np 2". Finally, on a multiple node calculation on a cluster, you can 
use "mpirun -np 8 -ppn 2". The "-np" tells mpirun the total number of 
MPI threads requested and the "-ppn" tells how many threads per node you 
want. In the present example, I am using 4 nodes and I want 2 MPI 
threads for each of them, so a total of 8. Of course, don't forget to 
set the OMP_NUM_TREADS as well.



On 20/09/2019 16:29, Nikhil Maroli wrote:
> Thank you very much for your reply.
> Could you please tell me how to use GPU in cp2k?
> I have installed all the libraries and compiled with cuda. I couldn't 
> find any instructions to assign GPU for the calculations.
>
> On Fri, Sep 20, 2019, 8:15 PM Pierre Cazade 
> <pierre.a... at gmail.com <mailto:pierre.a... at gmail.com>> 
> wrote:
>
>     Hello Nikhil,
>
>     Withe command "mpirun -n 42 cp2k.pop -i inp.inp -o -out.out", you
>     are requesting 42 MPI threads and not 42 OpenMP threads. MPI
>     usually relies on replicated data which means that, for a poorly
>     program software, it will request a total amount of memory which
>     the amount of memory required by a scalar execution times the
>     number of threads. This can very quickly become problematic, in
>     particular for QM calculations. OpenMP, however relies on shared
>     memory, the data is normally not replicated but shared between
>     threads and therefore, in an ideal scenario, the amount of memory
>     needed for 42 OpenMP threads is the same as a single one.
>
>     This might explains why you calculation freezes. You are out of
>     memory. On your workstation, you should only use the executable
>     "cp2k.ssmp" which is the OpenMP version. Then you don't need the
>     mpirun command:
>
>     cp2k.ssmp -i inp.inp -o -out.out
>
>     To control the number of OpenMP threads, set the env variable:
>     OMP_NUM_THREADS, e.g. in bash, export OMP_NUM_THREADS=48
>
>     Now, if you need to balance between MPI and OpenMP, you should use
>     the executable named cp2k.psmp. Here is such an example:
>
>     export OMP_NUM_THREADS=24
>     mpirun -n 2 cp2k.psmp -i inp.inp -o -out.out
>
>     In this example, I am requesting two MPI threads and each of them
>     can use up to 24 OpenMP threads.
>
>     Hope this clarifies things for you.
>
>     Regards,
>     Pierre
>
>     On 20/09/2019 14:09, Nikhil Maroli wrote:
>>     Dear all,
>>
>>     I have installed all the versions of CP2K in my workstation with
>>     2 x 12 core processor, total thread=48
>>
>>     I wanted to run cp2k in parallel using 42 threads, can anyone
>>     share the commands that i can use.
>>
>>     I have tried
>>
>>     mpirun -n 42 cp2k.pop -i inp.inp -o -out.out
>>
>>     After this command there is a rise in memory to 100 % and the
>>     whole system freezes. (i have 128GB ram).
>>
>>     Any suggestion will be greatly appreciated,
>>     -- 
>>     You received this message because you are subscribed to the
>>     Google Groups "cp2k" group.
>>     To unsubscribe from this group and stop receiving emails from it,
>>     send an email to cp... at googlegroups.com
>>     <mailto:cp... at googlegroups.com>.
>>     To view this discussion on the web visit
>>     https://groups.google.com/d/msgid/cp2k/39284c57-f6eb-463e-81a6-3a123596a9f2%40googlegroups.com
>>     <https://groups.google.com/d/msgid/cp2k/39284c57-f6eb-463e-81a6-3a123596a9f2%40googlegroups.com?utm_medium=email&utm_source=footer>.
>
>     -- 
>     Dr Pierre Cazade, PhD
>     AD3-023, Bernal Institute,
>     University of Limerick,
>     Plassey Park Road,
>     Castletroy, co. Limerick,
>     Ireland
>
>     -- 
>     You received this message because you are subscribed to the Google
>     Groups "cp2k" group.
>     To unsubscribe from this group and stop receiving emails from it,
>     send an email to cp... at googlegroups.com
>     <mailto:cp... at googlegroups.com>.
>     To view this discussion on the web visit
>     https://groups.google.com/d/msgid/cp2k/91cedcdb-79a0-a5f3-cf51-fde52abbba49%40gmail.com
>     <https://groups.google.com/d/msgid/cp2k/91cedcdb-79a0-a5f3-cf51-fde52abbba49%40gmail.com?utm_medium=email&utm_source=footer>.
>
> -- 
> You received this message because you are subscribed to the Google 
> Groups "cp2k" group.
> To unsubscribe from this group and stop receiving emails from it, send 
> an email to cp... at googlegroups.com 
> <mailto:cp... at googlegroups.com>.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/cp2k/CAMEzy6RbFpKfoc7dr94Z%3DNCzdzotQQCMA8W7w1x%3DLZe9zXXeNA%40mail.gmail.com 
> <https://groups.google.com/d/msgid/cp2k/CAMEzy6RbFpKfoc7dr94Z%3DNCzdzotQQCMA8W7w1x%3DLZe9zXXeNA%40mail.gmail.com?utm_medium=email&utm_source=footer>.

-- 
Dr Pierre Cazade, PhD
AD3-023, Bernal Institute,
University of Limerick,
Plassey Park Road,
Castletroy, co. Limerick,
Ireland

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190920/04aee345/attachment.htm>