[petsc-dev] OpenMP Support

[Dave Nystrom]

Is the pthreads support further along than the OpenMP support?  I have not
tried the pthreads support yet.  Does either the pthreads support or the
OpenMP support implement the matvec or do they just do vector type
operations?

Jed Brown writes:
 > On Tue, May 8, 2012 at 9:23 PM, Dave Nystrom <dnystrom1 at comcast.net> wrote:
 > 
 > > I see that petsc-dev now has some OpenMP support.  Would a serial, non-mpi
 > > code that uses petsc-dev be able to gain much performance improvement from
 > > it
 > > now for the case of doing sparse linear solve with cg and jacobi
 > > preconditioning?
 > >
 > 
 > The kernels are being transitioned to use the threadcomm, which enables
 > OpenMP and other threading models.
 > 
 > We anticipate that pthreads will provide the best performance because
 > operations can be less synchronous than with OpenMP (for which a parallel
 >  region implies barrier semantics). But if other parts of an application
 > are using OpenMP, it would be preferable for PETSc to also use OpenMP so
 > that it can share the same thread pool. The same applies to TBB.