[petsc-dev] PETSc programming model for multi-core systems

[Jed Brown]

On Fri, Nov 12, 2010 at 02:18, Barry Smith <bsmith at mcs.anl.gov> wrote:

> How do you get adaptive load balancing (across the cores inside a process)
> if you have OpenMP compiler decide the partitioning/parallelism? This was
> Bill's point in why not to use OpenMP. For example if you give each core the
> same amount of work up front they will end not ending at the same time so
> you have wasted cycles.


Hmm, I think this issue is largely subordinate to the memory locality (for
the sort of work we usually care about), but the OpenMP could be more
dynamic about distributing work.  I.e. this could be an OpenMP
implementation or tuning issue, but I don't see it as a fundamental
disadvantage of that programming model.  I could be wrong.

Jed
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