[Dune-devel] Long MPI startup

[Oliver Sander]

Hi Markus,

thanks for your help.  Indeed, your test program also requires
about 2.5 seconds to terminate, so there really is nothing
Dune-specific about it.

It is still annoying though.  My machine is a recent-ish ThinkPad Yoga,
with 8 cores, running Debian Testing.  I suppose I'll just have to
suck it up.

Best,
Oliver

On 15.12.20 10:19, Markus Blatt wrote:
> Hi,
> 
> 
> On Fri, Dec 11, 2020 at 12:19:56PM +0100, Oliver Sander wrote:
>>
>> I recently noticed that on my system (current Debian testing), the call to
>>
>>    MPIHelper::instance(argc, argv);
>>
>> takes between 2 and 3 seconds to complete.  This seems like a long time to me.
>> Is it to be expected?  Or is there a bug somewhere?
> 
> I don't think that we do anything specical during startup (besides calling
> MPI_Init). Hence I doubt that this is a Dune problem.
> 
> Maybe you cound try a minimal MPI program to compare?
> 
> #include <mpi.h>
> #include <iosteam>
> 
> int main(int argc, char** argv){
>    MPI_Init(&argc, argv);
>    int size, rank;
>    MPI_Comm_size(&size, MPI_COMM_WORLD);
>    MPI_Comm_rank(&rank, MPI_COMM_WORLD);
>    //Above should be all that DUNE does
>    std::cout<<"Hi, I am rank "<<rank<<" of "<<size<<"."<<std::endl;
>    MPI_Finalize();
>    return 0;
> }
> 
> BTW on my multicore machine (32 cores) it takes some time, too.
> Mabe you have a new machine? What MPI?
> 
> HTH,
> 
> Markus
> 

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 5198 bytes
Desc: S/MIME Cryptographic Signature
URL: <https://lists.dune-project.org/pipermail/dune-devel/attachments/20201215/9eedaca4/attachment.bin>