[petsc-dev] PETSc-Cuda with gfortran 4.7

Nystrom, William D wdn at lanl.gov
Wed Mar 13 09:26:34 CDT 2013


Asmund,

Do the failures you report below occur in cuda code that is ultimately compiled with nvcc?
I have not had problems compiling petsc-dev with cuda support on a Fedora 17 system
which uses gcc-4.7.2 and gfortran-4.7.2.  However, I have gcc 4.6.3 installed also and
have nvcc pointed at it by using the /usr/local/cuda/bin/nvcc.profile with a couple of lines
added.  So, when I build petsc-dev on my Fedora 17 system, it uses gcc-4.7.2 and
gfortran-4.7.2 for everything except cuda code located in .cu files.  I would worry about
removing some functionality in 4.7.2 with your suggested modification.

Thanks,

Dave

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________________________________________
From: petsc-dev-bounces at mcs.anl.gov [petsc-dev-bounces at mcs.anl.gov] on behalf of Åsmund Ervik [Asmund.Ervik at sintef.no]
Sent: Wednesday, March 13, 2013 6:32 AM
To: Karl Rupp
Cc: petsc-dev at mcs.anl.gov
Subject: Re: [petsc-dev] PETSc-Cuda with gfortran 4.7

Hi Karli,

I don't think this interferes with anything else, since all it does is
undef some C++ stuff which conflicts with CUDA, and was introduced in
gcc 4.7. That is, the things it undefines are also undefined when one
uses gcc 4.6 or lower. It is general for gcc >= 4.7.

Best regards,
\AA smund

On 12. mars 2013 15:13, Karl Rupp wrote:
> Hi Ervik,
>
> thanks for the hint. Do you happen to have any information on whether
> the suggested fix interferes with other versions of GCC or CUDA? Is this
> specific to version 4.7.2 or a 'general fix' for GCC?
>
> Best regards,
> Karli
>
>
> On 03/12/2013 02:35 AM, Åsmund Ervik wrote:
>> Hi all,
>>
>> (This suggestion is two lines of code, so I hope it will survive the git/hg apocalypse/transition today. If not, I'll resend it tomorrow.)
>>
>> Trying to compile PETSc with Cuda enabled, following the example in config/examples/arch-cuda-double.py, I get an error with gfortran 4.7.2 when making (configure works fine).
>> This error is apparently well-known with Cuda and gcc 4.7.2. To fix it, I added two lines to include/petsc-private/petscimpl.h:
>> #undef _GLIBCXX_ATOMIC_BUILTINS
>> #undef _GLIBCXX_USE_INT128
>> and everything works fine. I guess you should add this to petsc-dev, possibly with some if-statement around these lines.
>>
>> Best regards,
>> Åsmund Ervik
>>
>
>

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