[petsc-dev] OpenMP

[Junchao Zhang]

On Sat, Nov 6, 2021 at 3:51 PM Mark Adams <mfadams at lbl.gov> wrote:

> Yea, that is a bit inscrutable, but I see mumps is the main/only user of
> this:
>
> /* if using PETSc OpenMP support, we only call MUMPS on master ranks.
> Before/after the call, we change/restore CPUs the master ranks can run on */
>
> And I see _OPENMP is a macro for the release date (yyyymm) of the OMP
> version. It's not clear what the v5.0 is (
> https://www.openmp.org/specifications/)
>
{200505,"2.5"},{200805,"3.0"},{201107,"3.1"},{201307,"4.0"},{201511,"4.5"},{201811,"5.0"},{202011,"5.1"}

On Sat, Nov 6, 2021 at 4:27 PM Junchao Zhang <junchao.zhang at gmail.com>
> wrote:
>
>>
>>
>> On Sat, Nov 6, 2021 at 5:51 AM Mark Adams <mfadams at lbl.gov> wrote:
>>
>>> Two questions on OMP:
>>>
>>> * Can I test for the version of OMP? I want >= 5 and I see this, which
>>> looks promising:
>>> include/petscsys.h:#elif defined(_OPENMP) && *_OPENMP >= 201307* &&
>>> !defined(_WIN32)
>>>
>>> * What is the difference between HAVE_OPENMP and
>>> HAVE_OPENMP_SUPPORT.
>>>
>>> # this is different from HAVE_OPENMP. HAVE_OPENMP_SUPPORT checks if we
>> have facilities to support
>> # running PETSc in flat-MPI mode and third party libraries in MPI+OpenMP
>> hybrid mode
>> if self.mpi.found and self.mpi.support_mpi3_shm and self.pthread.found
>> and self.hwloc.found:
>> # Apple pthread does not provide this functionality
>> if self.function.check('pthread_barrier_init', libraries = 'pthread'):
>> self.addDefine('HAVE_OPENMP_SUPPORT', 1)
>>
>>
>>> Thanks,
>>> Mark
>>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20211106/f6079190/attachment-0001.html>