[mpich-discuss] MPICH2 and GPU

[Mandar Gurav]

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