Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] Checksuming in openmpi 1.4.1
From: Nysal Jan (jnysal_at_[hidden])
Date: 2010-09-01 01:52:55


Hi Gilbert,
Checksums are turned off by default. If you need checksums to be activated
add "-mca pml csum" to the mpirun command line.
Checksums are enabled only for inter-node communication. Intra-node
communication is typically over shared memory and hence checksum is disabled
for this case.
If you have built a debug version of Open MPI (--enable-debug), you can see
the checksum output by appending "-mca pml_base_verbose 5" to your command
line.
If you are interested in the relevant code it is located here -
ompi/mca/pml/csum

--Nysal

On Tue, Aug 31, 2010 at 1:22 PM, Gilbert Grosdidier <grodid_at_[hidden]>wrote:

> Bonjour,
>>
>> I'm not sure I understand how to trigger CHECKSUM use
>> inside of OpenMPI 1.4.1 (after digging in the FAQs, I got not
>> explanations, sorry):
>>
>> - Is checksuming activated by default and embedded automatically
>> within the Send/Recv pair mechanism, please ?
>> - If not, which MCA param(S) should I set to activate it ?
>> - Is there a time penalty for using it, please ?
>>
>> Thanks in advance for any help.
>>
>> --
>> Regards, Gilbert.
>>
>>
>>
> --
> *---------------------------------------------------------------------*
> Gilbert Grosdidier Gilbert.Grosdidier_at_[hidden]
> LAL / IN2P3 / CNRS Phone : +33 1 6446 8909
> Facult??des Sciences, Bat. 200 Fax : +33 1 6446 8546
> B.P. 34, F-91898 Orsay Cedex (FRANCE)
> ---------------------------------------------------------------------
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>