[petsc-users] cudaSetDevice

[Paul Mullowney]

Perhaps one can do cudaGetDevice() and cudaDeviceReset() in between the two
calls to PetscInitialize in the application code?
Provided no device data was allocated in between the two calls, this might
eliminate the error.

If you are doing this with multiple host threads (especially where the # of
CPU threads > # of GPUs), special care is required.

-Paul


On Tue, Oct 8, 2013 at 6:04 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> Harshad Sahasrabudhe <hsahasra at purdue.edu> writes:
> > You are right, it doesn't if you use just one PETSc. In our case, we
> > use 2 PETSc libraries (compiled separately, one each for complex and
> > double).
>
> Please remind us of this when you write.  We don't know everyone in your
> group at Purdue and it would simplify our figuring out what could cause
> the weird problems you encounter.
>
> > And in that case, when the second PETSc library is initialized,
> > cudaSetDevice throws an error. I can't think of any way in which both
> > the PETSc libraries could be initialized with CUDA on the same
> > process.
>
> This is a general issue of interoperability between multiple libraries
> that want to use CUDA.  How can we find out if someone else has already
> called cudaSetDevice?
>
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