[mpich-discuss] MPICH2 and GPU

[bob ilgner]

Thanks for this Mandar but the problem was with the MPI. The
-localonly as advised by Jayesh sorted it out. I had already killed
every CUDA function such as get or set of GPU devices before I tried
the mpich2 forum.

Thank you for your assist.

Regards, bob

On Wed, May 18, 2011 at 4:57 PM, Mandar Gurav <mandarwce at gmail.com> wrote:
> Hi Bob!
>
> Your problem seems to with CUDA rather than MPICH2.
>
> I think you must use following functions
> 1. cudaGetDeviceCount (int *count) - To get number of GPUs
> or cudaGetDevice (int *device) - to get the device currently being used.
>
> 2. if some available use following function to select the device.
> cudaSetDevice (int device)
>
> You can refer to following page.
>
> http://developer.download.nvidia.com/compute/cuda/2_3/toolkit/docs/online/group__CUDART__DEVICE.html
>
> As you said, "CUDA error calls tell me - no CUDA-capable device is
> detected." I think the issue is with some system variable... Since, I
> am not a cuda expert. I could execute the MPI- GPGPU hybrid jobs on my
> linux cluster...
>
> I would rather recommend you to post this problem on CUDA mailing list also.
>
> Hope this will help you.
>
> -- Mandar Gurav.
>
>
>
> On Wed, May 18, 2011 at 8:04 PM, Jayesh Krishna <jayesh at mcs.anl.gov> wrote:
>> Hi,
>>  Try using the "-localonly" option (or "-localroot" option) to use the GPUs on the local node. Supporting usage of GPUs on non-local nodes is in our to-do list.
>>
>> Regards,
>> Jayesh
>>
>> ----- Original Message -----
>> From: "bob ilgner" <bobilgner at gmail.com>
>> To: mpich-discuss at mcs.anl.gov
>> Sent: Wednesday, May 18, 2011 1:25:45 AM
>> Subject: [mpich-discuss] MPICH2 and GPU
>>
>> Dear All,
>>
>> I have two GPUs on 1 motherboard and want to use MPI to control the
>> CUDA on each GPU.
>>
>> Program runs well in Windows 7 environment without MPICH2
>>
>> When using "mpiexec -n 2 progname" then the CUDA error calls tell me
>> "no CUDA-capable device is detected".
>>
>> i.e. the error only arises in the MPI environment.
>>
>> Has anyone else experienced this before and is there something I need
>> to do with Mpich2 to be able to detect the GPUs ?
>>
>> Regards, bob
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>
>
>
> --
> Mandar Gurav
> http://www.mandargurav.org
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